Entries |
Document | Title | Date |
20080211579 | METHOD AND APPARATUS FOR OPTIMIZING POWER DISSIPATION IN A LOW NOISE AMPLIFIER - A method and a low noise amplifier are provided such that the low noise amplifier has a power dissipation that is adaptive to the noise interference levels. The low noise amplifer includes (i) first, second and third differential amplifiers connected in series each having a terminal for receiving a power supply current; and (ii) first and second switches responsive to a control signal, the first and second switches configured such that, (a) when the control signal is in a first state, the first switch and the second switch enable independent currents to flow in the terminals for receiving a power supply current; and (b) otherwise, the first switch and the second switch enable the terminal for receiving a power supply current of the second differential amplifier to reuse a current provided to the terminal for receiving a power supply current of the third differential amplifier. The control signal is provided by a radio frequency noise power detector, which senses an output signal of the low noise amplifier. | 09-04-2008 |
20080224775 | Variable Gain Amplifier - A variable gain amplifier includes multiple gain stages. Each gain stage includes a gain transistor and a cascode transistor to form a cascode amplifier, and a current diversion transistor to divert current away from a cascode transistor to reduce gain in the stage. A control circuit is included to maintain substantially constant drain-to-source voltage and drain current in the gain transistor. | 09-18-2008 |
20080258814 | VARIABLE GAIN AMPLIFIER AND METHOD FOR ACHIEVING VARIABLE GAIN AMPLIFICATION WITH HIGH BANDWIDTH AND LINEARITY - Various example embodiments are disclosed. According to one example embodiment, a high bandwidth, fine granularity variable gain amplifier (“VGA”) may comprise an attenuator, a gain block and a gain adjustment control. The attenuator may comprise at least one pair of attenuator differential input nodes and at least one pair of attenuator differential output nodes. The gain block may comprise at least one pair of gain block differential input nodes coupled to the at least one pair of attenuator differential output nodes and at least one pair of gain block differential output nodes. The gain adjustment control may be configured to adjust a gain of the gain block. | 10-23-2008 |
20080265991 | Gain control module and applications thereof - A gain control module includes an amplifier, a least significant bit (LSB) gain stage, and a most significant bit (MSB) gain stage. The amplifier includes a first input, a second input, and an output. The LSB gain stage produces a LSB gain based on an LSB portion of a gain control signal, wherein the LSB gain stage receives an input signal. The MSB gain stage produces an MSB gain based on an MSB portion of the gain control signal, wherein the MSB gain stage is coupled to the LSB gain stage, the first input of the amplifier, and the output of the amplifier, wherein the gain control module amplifies the input signal in accordance with the gain control signal. | 10-30-2008 |
20080265992 | Transconductance Stage Arrangement - The present invention relates to a voltage-to-current transconductance stage arrangement comprising a single-ended input, an emitter-coupled pair of transistors, comprising a first transistor and a second transistor, the emitter of a third transistor, being connected to the collector of said first transistor, and differential output. It further comprises at least one common-collector transistor comprising a fourth transistor connected to the base of said second transistor preferably or optionally also and a fifth transistor connected to the base of said third transistor. The size of said fourth, or fourth and fifth transistors considerably exceed the sizes of said second and third transistors. They are biased at ‘off-state’. An extra inductor at the collector of the transistor may be applied to further increase linearity. | 10-30-2008 |
20080297250 | INTEGRATED CIRCUIT SYSTEM FOR CONTROLLING AMPLIFIER GAIN - An integrated circuit system comprising: forming a differential amplifier including: forming a first transistor, coupling a second transistor to the first transistor in a high gain configuration, and coupling a third transistor, having a low gain configuration, in parallel with the second transistor; and adjusting a gain of the differential amplifier by adjusting a ratio of the size of the second transistor to the size of the first transistor. | 12-04-2008 |
20080297251 | DIGITALLY ADJUSTED VARIABLE GAIN AMPLIFIER (VGA) USING SWITCHABLE DIFFERENTIAL PAIRS - A variable gain amplifier including a stage. The stage having a set of switchable differential pairs. The stage providing a gain range to a signal and adjusting a gain of the signal. At least one differential pair in each stage is permanently enabled. The variable gain amplifier may include a plurality of cascaded stages including the stage. In addition, the variable gain amplifier may be adjusted through an interleaved thermometer coding method. | 12-04-2008 |
20080303592 | Differential amplifier circuit and A/D converter - PMOS transistors are interposed parallel to each other between a node, which is a first output part, and a power supply; and PMOS transistors are interposed in parallel to each other between a node, which is a second output part, and the power supply. Output voltages in time of a balanced state in which an input potential difference between an input voltage and a reference voltage is “0” are both set to a reference output common voltage by a replica circuit and a comparator. The reference output common voltage of the replica circuit is set so that the potential difference between the power supply voltage and the output common voltage becomes a value lower than a threshold voltage of the diode connected PMOS transistors. | 12-11-2008 |
20090009245 | Circuit for Adjusting an Impedance - The invention relates to a circuit for adjusting an impedance between two terminals, said impendance including the input impedance of the circuit. The aim of the invention is to enlarge the adjustment range and to stabilize—the operating behavior of such a circuit. For this purpose, the circuit comprises amplifiers, adjusting means with which amplification of at least one amplifier and/or the circuit can be changed in general and the impedance between the two terminals can be modified by influencing the one or more adjusting means. | 01-08-2009 |
20090009246 | ELECTRONIC CIRCUIT - An electronic circuit includes a differential amplifier circuit, a first smoothing circuit, a second smoothing circuit and a first switch. The differential amplifier circuit receives a digital input signal and a reference signal. The first smoothing circuit smoothes the digital input signal with a first capacitance value. The second smoothing circuit smoothes the digital input signal with a second capacitance value larger than the first capacitance value. The first switch selects one of output signals from the first smoothing circuit and the second smoothing circuit as the reference signal. | 01-08-2009 |
20090015331 | CURRENT SENSE AMPLIFIER FOR VOLTAGE CONVERTER - A variable gain amplifier comprising a differential input amplifier comprising a pair of transistors each having an input across which an input voltage is provided, the transistors being coupled such that each transistor is provided in series with a respective current source providing a reference current and whereby a current is developed across a resistor element coupling the transistors that is proportional to the voltage between the inputs; further comprising further transistors each coupled in series with a transistor of the transistor pair, and wherein the further transistors are arranged such that a current is developed in each further transistor due to the voltage provided across the inputs that is substantially equal to, in one further transistor, a sum of the reference current and the current in the resistor element, and in the other further transistor, a difference between the reference current and the current in the resistor element; further comprising a gain stage for developing currents equal to a gain factor multiplied by the sum and difference currents and for developing an output signal proportional to the gain factor multiplied by the current through the resistor element; further comprising an interface for selectively providing a signal proportional to a variable across the inputs of the differential amplifier to drive the output signal to an output value; and a gain setting circuit responsive to the output value that produces a gain setting signal to adjust the gain of the variable gain amplifier. | 01-15-2009 |
20090051428 | AGC CIRCUIT - This invention offers an AGC circuit that prevents disturbance in an output waveform when an input signal varies abruptly. A first terminal of a capacitor is connected with an output terminal of a variable gain amplifier and a second terminal of the capacitor is connected with a non-inverting input terminal (+) of a differential amplifier. A reference voltage Vref | 02-26-2009 |
20090051429 | HIGH RESOLUTION VARIABLE GAIN CONTROL - A gain circuit includes an analog section with variable gain and a digital section with variable gain. The gain steps for the digital section have a higher resolution than the gain steps for the analog section. In some implementations, gain steps can be achieved much finer than 0.1 db or less without sensitivity to device tolerances. | 02-26-2009 |
20090051430 | Variable gain circuit - Disclosed is a variable gain circuit, which operates in a region where the gain varies substantially exponentially with respect to a control voltage, having an operation region in which the gain varies substantially with an exponential function | 02-26-2009 |
20090058524 | RECEIVED SIGNAL STRENGTH INDICATOR SELF-CALIBRATING GAIN OF LIMITER - A received signal strength indicator according to an aspect of the invention may include a gain calibration section including a calibration limiter, a calibration load unit and a comparison and adjustment unit. The calibration load unit is connected to output terminals of the calibration limiter, and generating an output differential voltage whose gain is a unit gain when a predetermined input differential voltage is input to the calibration limiter, and a comparison and adjustment unit comparing the input differential voltage with the output differential voltage, and adjusting an output of a variable current source included in the calibration limiter so that the input differential voltage becomes identical to the output differential voltage. | 03-05-2009 |
20090072903 | Variable Gain Amplifier Having Variable Gain DC Offset Loop - A variable gain amplifier and offset cancellation loop circuit and methods for tracking and correcting DC offset errors that may vary in accordance with the gain of the variable gain amplifier. The circuit is designed to provide tracking of rapid changes in the offset error while maintaining a desired overall frequency response of the combined variable gain amplifier and offset loop. The offset loop cancellation circuit has a wide enough bandwidth to allow the offset cancellation loop to track rapid changes in offset errors that result from rapid changes to the amplifier's gain setting. A control circuit is provided to prevent the large offset cancellation loop bandwidth from having a detrimental effect on the amplifier's overall bandwidth when the amplifier is set to high levels of forward gain by adjusting the offset cancellation loop gain as the forward gain of the amplifier is altered. | 03-19-2009 |
20090072904 | Variable Gain Amplifier Having Dual Gain Control - An electronic amplifier circuit that provides improved gain control linearity characteristics resulting from having a controllable field effect transistor (FET) acting as a degeneration resistance (degeneration resistance FET) and a controllable load resistance FET. The overall gain function of the amplifier exhibits improved linearity in part due to the presence of the load FET, which tends to cancel the nonlinear behavior emanating from the degeneration FET. The circuit also includes a control circuit for generating non-linear control signals that are responsive to process characteristics of the FETs, such that the degeneration resistance FET and load resistance FETs may be controlled more consistently and independently from process variations. | 03-19-2009 |
20090072905 | VARIABLE GAIN AMPLIFIER HAVING WIDE GAIN VARIATION AND WIDE BANDWIDTH - There is provided a variable gain amplifier that is implemented with a CMOS device and has wide band variation and wide bandwidth by a predetermined exponential function. A variable gain amplifier having wide gain variation and wide bandwidth according to an aspect of the invention may include: a differential amplification section differentially amplifying an input signal according to a gain adjustment signal; and a gain adjustment section supplying the gain adjustment signal on the basis of an approximated exponential function determined according to a predetermined bias current, and adjusting a gain of the differential amplification section. | 03-19-2009 |
20090079500 | ANALOG VARIABLE GAIN AMPLIFIER WITH IMPROVED DYNAMIC RANGE CHARACTERISTICS - An automatic gain control (AGC) system and method for implementing a wide dynamic range automatic gain control (AGC) are disclosed. The AGC system features a large gain adjustment suitable for integration in silicon tuners. The AGC structure employs a pair of classical current steering stages, architecturally arranged to share the gain back-off characteristic in a novel “ping-pong” arrangement. The AGC system and method deliver a wide dynamic range at low power dissipation in radio frequency (RF) systems, but may be implemented as well in other applications. | 03-26-2009 |
20090079501 | PROGRAMMABLE GAIN CIRCUIT AND AMPLIFICATION CIRCUIT - One aspect of the embodiments relates to a programmable gain circuit including an amplification unit amplifying an input signal, an input resistor coupled to an input terminal of the amplification unit, a feedback resistor coupled between an output terminal of the amplification unit and the input terminal of the amplification unit, a first switch switching a resistance value of the feedback resistor, a second switch switching a resistance value of the input resistor, and a control unit controlling the second switch such that the second switch switches the resistance value of the input resistor when the first switch switches the resistance value of the feedback resistor. | 03-26-2009 |
20090085660 | AGC MODULE AND METHOD FOR CONTROLLING NOISE FIGURE AND INTERMODULATION CHARACTERISTICS THEREIN - An Automatic Gain Control (AGC) module for controlling Noise Figure (NF) and IM characteristics therein is disclosed. The AGC module comprises a plurality of AGC stages. Each AGC stage comprises a differential amplifier circuit, an input signal transistor and a current-steering circuit. Differential amplifier circuits of the plurality of AGC stages receive control signals at their differential inputs and their output is connected to a common load. The input signal transistors of the plurality of AGC stages receive a common input signal and is further coupled to the differential amplifier circuit and the current-steering circuit. The current-steering circuits and the control signals at the differential amplifier circuits control gain of the each AGC stage of the plurality of AGC stage, which is used to control the NF and the IM characteristics. | 04-02-2009 |
20090085661 | METHODS AND APPARATUS FOR PROCESS INVARIANT TRANSCONDUCTANCE - In one aspect, a resistor process invariant transconductor is provided. The transconductor comprises a voltage input configured to receive at least one voltage signal, a current output configured to provide at least one current signal, wherein a ratio between the at least one voltage signal and the least one current signal forms a total transconductance for the transconductor, and a circuit including at least one integrated resistor connected between the voltage input and the current output, the circuit adapted to maintain the total transconductance substantially constant across variation of the at least one integrated resistor. | 04-02-2009 |
20090091387 | SWITCHED-CAPACITOR VARIABLE GAIN AMPLIFIER HAVING HIGH VOLTAGE GAIN LINEARITY - Provided is a switched-capacitor variable gain amplifier having high voltage gain linearity. According to the above amplifier, a sampling capacitor is shared and used at a sampling phase and an amplification phase, and thus a voltage gain error caused by capacitor mismatch can be reduced. Also, using a unit capacitor array enables circuit design and layout to be simplified. Further, in the amplifier, a voltage gain can be easily controlled to be more or less than 1, as necessary, and power consumption and kT/C noise can be reduced by a feedback factor that is relatively large, so that gain amplification performance can be improved. | 04-09-2009 |
20090102559 | MONOTONIC VARIABLE GAIN AMPLIFIER AND AN AUTOMATIC GAIN CONTROL CIRCUIT - A monotonic variable gain amplifier which can be controlled to achieve a desired gain. The amplifier has: —at least two amplifier stages ( | 04-23-2009 |
20090108935 | Variable gain amplifier including series-coupled cascode amplifiers - A variable gain amplifier to convert an amplifier input voltage to an amplifier output voltage, the variable gain amplifier includes: a plurality of cascode amplifiers coupled in series; a plurality of switching transistor pair circuits coupled in series; and a bias circuit coupled to provide bias voltages to each of the plurality of cascode amplifiers; wherein each of the switching transistor pair circuits is further coupled between two consecutive ones of the cascode amplifiers; a first one of the cascode amplifiers is configured to receive the amplifier input voltage; and a last one of the cascode amplifiers is configured to provide the amplifier output voltage. | 04-30-2009 |
20090128239 | Multistage Tuning-Tolerant Equalizer Filter with Improved Detection Mechanisms for Lower and Higher Frequency Gain Loops - The present invention provides an equalizer filter for compensating a received distorted signal for frequency dependent signal modifications introduced by a transmission channel, the received signal having an amplitude. The filter comprises at least one amplifying compensation stage having a gain and a saturation level, at least one limiting amplifier, and gain control means for controlling the gain of the at least one amplifying compensation stage, the gain control means comprising at least one comparator circuit comparing filtered input and output signals of the limiting amplifier, the at least one comparator circuit comprising a bias current source. The bias current source is adapted to deliver a variable current. | 05-21-2009 |
20090140808 | GAIN CONTROL CIRCUIT - A gain control circuit including a resistor with a first terminal and a second terminal; an operational amplifier with an inverting terminal thereof electrically coupled to said first terminal of said resistor; a non-inverting terminal thereof; and an output terminal thereof; an amplifier circuit for transforming the voltage change of said operational amplifier output into a substantially exponential current change; wherein the output of said amplifier circuit is electrically coupled to said inverting terminal of said operational amplifier. The above described gain control circuit is able to perform wide bandwidth input signal buffering with linearity under low voltage and low power conditions. The circuit also offers low output impedances without the need of additional buffers and hence minimizing circuit size and manufacturing costs. | 06-04-2009 |
20090140809 | High Performance Variable Gain Amplifier, Method of Use and Design Structure - A circuit of high performance variable gain amplifier, method of use and design structure on which the subject circuit resides is provided. The circuit comprises a plurality of differential stages having a common input, and output, a common control level input CM and respective individual control level inputs C | 06-04-2009 |
20090140810 | Variable Gain Amplifier - The present invention relates to a variable gain amplifier. The variable gain amplifier in an ultrasound includes an attenuator. The attenuator includes resistor strings each having a plurality of resistors connected in series to each other and a gain control unit. The gain control unit has tap inputs taken from a plurality of junctions between a first resistor string receiving a first input signal and a second resistor string receiving a second input signal. The gain control unit is configured to provide an attenuated differential input signal based on the tap inputs. The variable gain amplifier includes an amplifying unit having a feedback amplifying section configured to amplify the attenuated differential input signal to output a first amplified signal and a clipping amplifying section configured to amplify the first amplified signal to output a second amplified signal that falls within a predetermined voltage range. | 06-04-2009 |
20090153245 | VARIABLE-GAIN WIDE-DYNAMIC-RANGE AMPLIFIER - A variable-gain wide-dynamic-range amplifier including an amplifier module, a control unit, and an output current regulating circuit is provided. The amplifier module amplifies an input signal. The amplifier module includes several amplifier units coupled to each other in parallel. The gains of the amplifier units are different. The control unit enables at least one of the amplifier units according to a gain control signal. The at least one of the amplifier units which is enabled is for outputting a current signal in response to the input signal. The output regulating circuit is for receiving the current signal and outputting an output signal accordingly by regulating the magnitude of the current signal under the control of the control unit. Each of the amplifier units is coupled to the output current regulating circuit in series. The control unit is for controlling the output current regulating circuit according to the gain control signal. | 06-18-2009 |
20090153246 | Method and system for varying gain exponentially with respect to a control signal - A method for varying gain exponentially with respect to a control signal is provided. The method includes receiving a primary control signal. A secondary control signal is generated based on the primary control signal. The secondary control signal is provided to a variable gain amplifier and is operable to exponentially vary a gain for the variable gain amplifier with respect to the primary control signal. | 06-18-2009 |
20090160554 | AMPLIFIER ARRANGEMENT - A gain-controlled RF amplifier system has an input node and an output node. The system has a plurality of amplifier devices, selectively connectable between the input node and the output node. The amplifier devices are placed in circuit according to a measured gain derived by comparing a magnitude of a signal input to the input node against a magnitude of a signal output from the output node, and a desired value of gain. | 06-25-2009 |
20090195310 | LNA HAVING A POST-DISTORTION MODE AND A HIGH-GAIN MODE - A differential low noise amplifier (LNA) is operable in a selectable one of two modes. The LNA includes a first transistor, a second transistor, a third transistor and a fourth transistor. In the first mode (PDC mode), the four transistors are configured to operate as a post-distortion cancellation (PDC) LNA. The third and fourth transistors operate as cancel transistors that improve linearity, but reduce LNA gain somewhat. In the second mode (high gain mode), the third and fourth transistors are configured so that amplified versions of the LNA input signal that they output are added to amplified versions of the LNA input signal that are output by the first and second main transistors, resulting in increased gain. Multiplexing circuits are provided within the LNA so that the LNA is configurable into a selectable one of the two modes by controlling a digital mode control signal supplied to the LNA. | 08-06-2009 |
20090231041 | Commutating Amplifier with Wide Dynamic Range - Variable gain commutating amplifier apparatus and methods for use in a polar modulator are described. The apparatus may include two or more commutating amplifier stages configured to be switched to an output load based on a desired amplitude and/or transmit power level. The amplifier stages may include cross-coupled differential pairs to cancel RF carrier feedthrough. An additional R-2R ladder circuit may be provided to further extend the dynamic range by reducing the output power at the lowest output stages. | 09-17-2009 |
20090256635 | LINEAR-IN-DB VARIABLE GAIN AMPLIFIER - A variable gain amplifier (VGA) with a gain thereof exponential to a control voltage thereof. The variable gain amplifier (VGA) comprises an exponential DC converter, and a linear voltage multiplier. The exponential DC converter receives the control voltage and generates an exponential voltage which is exponential to the control voltage. The linear voltage multiplier is coupled to the exponential DC converter and has a gain proportional to the exponential voltage of the exponential DC converter. | 10-15-2009 |
20090256636 | Amplifier Arrangement and Method for Signal Amplification - An amplifier arrangement comprises a signal input (Iin+, Iin−) to receive a signal to be amplified, a signal output (Out) to provide an amplified signal, an amplifier stage (AS) coupled between the signal input (Iin+, Iin−) and the signal output (Out), a switchable dynamic biasing stage (DB) with an input coupled to the signal input (Iin+, Iin−), a switchable gain boosting stage (GB) with an input coupled to the signal input (Iin+, Iin−), and a switching device (SD) coupled to the amplifier stage (AS) such that either an output of the switchable dynamic biasing stage (DB) or an output of the switchable gain boosting stage (GB) are coupled to the amplifier stage (AS). In one embodiment, by enabling the switchable dynamic biasing stage (DB) in an initial large-signal phase of amplification and the switchable gain boosting stage (GB) in a latter small-signal phase of amplification by means of the switching device (SD), high gain and low current consumption are simultaneously realised. Furthermore, a method for signal amplification is disclosed. | 10-15-2009 |
20090261903 | VARIABLE GAIN RF AMPLIFIER - A variable gain amplifier having an input node, a variable current source including a control input coupled to the input node, first and second branches coupled in parallel between a first supply terminal and the variable current source, the first and second branches defining a differential pair arranged to be controlled by first and second differential gain signals and having first and second output terminals, one of the output terminals including an output node of the variable gain amplifier; and a potential divider having a middle node coupled to the first and second output terminals, wherein the middle node is also coupled to the input node by a capacitor. | 10-22-2009 |
20090267692 | DIGITALLY VARIABLE GAIN AMPLIFIER USING MULTIPLEXED GAIN BLOCKS - A digitally variable gain amplifier comprising a front-end stage, a level shifter stage, and an output amplifier stage. The front-end stage comprises a high gain pre-amplifier and a low gain pre-amplifier driven in parallel by a differential input signal. A coarse gain control is realized by enabling only one pre-amplifiers at a time, while the differential input signal remains connected to the inputs of the disabled pre-amplifier. An attenuator following each pre-amplifier provides fine gain control. The enabled pre-amplifier amplifies the differential input signal and outputs a first dc voltage level. The disabled pre-amplifier is placed into a standby ready mode and outputs a second dc voltage level that is greater in magnitude than the first dc voltage level. The level shifter stage performs a minimum voltage selection operation to automatically select and level shift the amplified differential input signal, and further pass the signal to the output amplifier stage. | 10-29-2009 |
20090273401 | Method and System for Multiple Tuner Application Using a Low Noise Broadband Distribution Amplifier - An active splitter circuit arrangement includes a first amplification module having a number of first input ports and first output ports. The first amplification module is configured to provide first stage amplification to a received input signal and produce from the amplified input signal a number of output signals, each substantially matching the input signal. Also included is a first gain control device having a number of gain input ports respectively coupled to the first output ports and a gain output port coupled to at least one of the first input ports. The first gain control device is configured to control a gain of the first amplification module. Next, a number of second amplification modules corresponding to the number of output signals has a number of second input ports respectively coupled to the first output ports. Each second amplification module is configured to receive a control signal from the second gain control device, provide second stage amplification to a corresponding one of the number of output signals based upon the control signal and produce an amplified output signal. | 11-05-2009 |
20090278601 | Preamplifier and method for calibrating offsets therein - A preamplifier includes cascade-connected amplifying circuits, and at least one of the cascade-connected amplifying circuits includes a differential switch pair circuit, a comparator and energy storing elements. The differential switch pair circuit has a pair of differential inputs and a pair of differential outputs. The comparator -outputs a comparison signal by comparing the differential outputs. The energy storing elements are respectively and selectively coupled to one of the differential outputs based on the comparison signal to adjust potential of the differential outputs. A method for calibrating offsets in a preamplifier is also disclosed herein. | 11-12-2009 |
20090284316 | AMPLIFIER DEVICE - An electronic circuit arrangement is provided which comprises an input terminal configured to input an input signal to be amplified and an output terminal configured to output the amplified input signal as an output signal. A signal path is defined between the input terminal and the output terminal. An amplifier unit having an amplifier gain is provided and being configured to amplify the input signal and for generating the output signal. A variation of an operational current of the amplifier unit is configured to provide a variation of the amplifier gain. The amplifier unit is arranged within the signal path. Furthermore a gain control unit is configured to control the gain of the amplifier unit by adjusting the operational current of the amplifier unit. The gain control unit is arranged outside the signal path. | 11-19-2009 |
20090302946 | VARIABLE GAIN AMPLIFIER HAVING LINEAR-IN-dB GAIN CHARACTERISTIC - A variable gain amplifier (VGA) with a linear-in-dB gain characteristic is provided. The VGA includes: a control signal converter which converts an input gain control signal V | 12-10-2009 |
20090302947 | SEMICONDUCTOR DEVICE - A semiconductor device including: a gain control circuit; a first circuit which is controlled a gain to be constant by the gain control circuit; and a bias circuit connected to the first circuit, wherein the first circuit including a first transistor; and a load resistance, an amplification factor or an attenuation factor of the first circuit is proportionate to a product of a transconductance of the first transistor and a resistance value of the load resistance, and a voltage applied to the load resistance is set as an output of the semiconductor device, the bias circuit generates and outputs a differential current of a current that is proportionate to a drain current flowing into the first transistor and a current that is inversely proportionate to the load resistance value, and an output of the bias circuit is connected to an output node of the first circuit. | 12-10-2009 |
20090302948 | POST AMPLIFIER WITH SELECTABLE GAIN - A selectable gain amplifier includes two or more selectable gain stages, each gain stage having a first input coupled to receive an input signal, a second input, and an output. The amplifier further includes and two or more feedback paths coupled between the outputs and the second inputs of the selectable gain stages. | 12-10-2009 |
20100001798 | DIGITALLY PROGRAMMABLE TRANSCONDUCTANCE AMPLIFIER AND MIXED-SIGNAL CIRCUIT USING THE SAME - The present invention relates to an trans-conductance amplifier, cooperating with a digital programmable current mirrors, can be applied to digital programmable current-mode integrated circuits, voltage control oscillators, adaptive frequency adjust mechanism, adaptive continuous analog filters via the corresponding trans-conductance adaptation controlled by the digital control signals. The present invention disclosed a digital programmable current mirror suitable for the second stage of the trans-conductance amplifier so as to reform the fixed gain trans-conductance amplifier to be digitally programmable. | 01-07-2010 |
20100007418 | INPUT SYSTEM FOR A VARIABLE GAIN AMPLIFIER HAVING CLASS-AB TRANSCONDUCTANCE STAGES - A variable gain amplifier includes an attenuator having a plurality of pairs of tap points, and a plurality of pairs of gm cells, wherein each pair of gm cells is coupled to a corresponding pair of the tap points, and each pair of gm cells is constructed and arranged to operate as a multi-tanh cell. | 01-14-2010 |
20100007419 | Instrumentation Input Systems - An input stage for an instrumentation system may include a resistor coupled between an input terminal and a summing node, and an amplifier arranged to maintain the voltage at the summing node. In anther embodiment, an instrumentation input system may include an input stage to receive a signal to be measured, and a variable gain amplifier having an input coupled to an output of the input stage, wherein the variable gain amplifier comprises two or more gain stages. A variable gain amplifier may include an attenuator having an input and a series of tap points and a series of low-inertia switches to steer outputs from the attenuator to an output terminal. | 01-14-2010 |
20100013557 | Current-controlled CMOS (C3MOS) fully differential integrated wideband amplifier/equalizer with adjustable gain and frequency response without additional power or loading - Current-controlled CMOS (C3MOS) fully differential integrated wideband amplifier/equalizer with adjustable gain and frequency response without additional power or loading. A novel approach is presented by which adjustable amplification and equalizer may be achieved using a C3MOS wideband data stage. This may be referred to as a C3MOS wideband data amplifier/equalizer circuit. This employs a wideband differential transistor pair that is fed using two separate transistor current sources. A switchable RC network is communicatively coupled between the sources of the individual transistors of the wideband differential transistor pair. There are a variety of means by which the switchable RC network may be implemented, including using a plurality of components (e.g., capacitors and resistors connected in parallel). In such an embodiment, each component may have an individual switch to govern its connectivity in the switchable RC network thereby allowing a broad range of amplification and equalization to be performed. | 01-21-2010 |
20100052786 | AUTOMATIC GAIN CONTROL APPARATUS AND TECHNIQUE - An amplifier includes steering stages to receive a control signal and collectively provide an output signal. Each steering stage receives an associated input signal and contributes to the output signal based on the control signal. The amplifier includes an attenuator to selectively attenuate the input signals to form different gain control ranges for the amplifier. | 03-04-2010 |
20100073090 | CURRENT SENSE AMPLIFIER - A system includes a current sense amplifier to receive an input voltage based on a sense current provided to load circuitry. The current sense amplifier is configured to generate an output voltage from the input voltage based, at least in part, on one or more reconfigurable characteristics of the current sense amplifier. The system also includes a microcontroller to compare the output voltage from the current sense amplifier to one or more programmable thresholds. The microcontroller is configured to direct a current controller to regulate the sense current provided to the load circuitry according to the comparison. | 03-25-2010 |
20100090765 | Programmable Gain Amplifier - A programmable gain amplifier comprising alternatively selectable parallel circuits in a front end and independently selectable serial amplification circuits in a back end. The front end may include, for example, a plurality of transconductors in parallel and each configured to generate a current proportional to a received voltage. A ratio of the generated current to the received voltage being different for each of the transconductors. The back end is configured to receive an output of a selected member of the parallel circuits and may include a plurality of current or voltage mode amplifiers in series. For example, the back end may include a plurality of current-mode gain stages and switches configured to control which of the current-mode gain stages are used to amplify the output of the front end. The programmable gain amplifier may be used between a signal receiver and an analog to digital converter. | 04-15-2010 |
20100123520 | Low Noise Binary-Coded Gain Amplifier and Method for Time-Gain Compensation in Medical Ultrasound Imaging - A low noise variable gain amplifier and method for processing received signals in an ultrasound medical imaging system is disclosed. Unlike solutions known from the prior art, the signals are amplified by a binary-coded gain amplifier having its amplification factor progressively increased during the penetration of the transmitted pulse into a patient's body. This allows enhancing both the system dynamic range and Signal to Noise Ratio. | 05-20-2010 |
20100156534 | GAIN CONTROL DEVICE AND AMPLIFIER USING THE SAME - Provided are a gain control device and an amplifier using the gain control device. The gain control device includes a first input resistance unit having a first variable resistor whose resistance is linearly variable and a first fixed resistor respectively receiving a first input signal and a second input signal having a sign different from the first input signal and outputting current through a first output terminal, and a second input resistance unit having a second fixed resistor and a second variable resistor whose resistance is linearly variable respectively receiving the first input signal and the second input signal and outputting current through a second output terminal. | 06-24-2010 |
20100156535 | INTEGRATED PROGRAMMABLE GAIN AMPLIFIER CIRCUIT AND SYSTEM INCLUDING THE CIRCUIT - An integrated programmable gain amplifier circuit that receives at an input an analog signal, circuit including an operational amplifier and a gain setup network comprising resistive elements and selection elements, which may be controlled in order to setup the gain of the amplifier circuit. The gain setup network further includes capacitive elements, for defining, together with the resistive elements and the operational amplifier, an anti-aliasing filter of the active RC type. | 06-24-2010 |
20100194478 | EQUALIZER FILTER WITH MISMATCH TOLERANT DETECTION MECHANISM FOR LOWER AND HIGHER FREQUENCY GAIN LOOPS - The present invention provides an equalizer filter for compensating a received distorted signal for frequency dependent signal modifications introduced by a transmission channel. The equalizer filter comprises at least one compensation stage. A compensation stage has at least one gain parameter. Different compensation stages may have different gain parameters. The equalizer filter according to embodiments of the present invention comprise at least one switch, the at least one switch being for changing at least one of the gain parameters in time in function of the compensated signal. In embodiments of the present invention, for every gain parameter a switch may be present in the equalizer filter. | 08-05-2010 |
20100237943 | Auto gain controllers, and communication terminals having the same - An auto gain controller is provided. The auto gain controller includes a variable gain amplification unit configured to receive differential input signals, adjust an amplification gain based on an auto gain control voltage and output differential output signals. The auto gain controller also includes a peak detector configured to detect at least one peak value among the amplified differential output signals, a comparator configured to compare the at least one detected peak value with a reference voltage and generate a comparison signal, and a voltage adjusting circuit configured to adjust the auto gain control voltage and the reference voltage based on the comparison signal. | 09-23-2010 |
20100283543 | Variable gain amplifier - Various amplifier configurations having increased bandwidth, linearity, dynamic range, and less distortion are shown and disclosed. To increase bandwidth in a transimpedance amplifier, a replica circuit is created to replicate a degeneration resistance, or the resistance or value that relates to a feedback resistance. From the replica circuit, the replicated values are mirrored and processed to control a FET switch which modifies a degeneration resistance. The FET switch control signal is related to the feedback resistance and modifies the degeneration resistance to thereby maintain the product of the feedback resistance and the degeneration resistance as a constant. In another embodiment, a second switch controlled by an automatic gain control signal is established between a first stage amplifier and a second stage amplifier to improve dynamic range and bandwidth without degrading other amplifier specifications. | 11-11-2010 |
20100289583 | VARIABLE GAIN RF AMPLIFIER - A variable gain amplifier having an input node, a variable current source including a control input coupled to the input node, first and second branches coupled in parallel between a first supply terminal and the variable current source, the first and second branches defining a differential pair arranged to be controlled by first and second differential gain signals and having first and second output terminals, one of the output terminals including an output node of the variable gain amplifier; and a potential divider having a middle node coupled to the first and second output terminals, wherein the middle node is also coupled to the input node by a capacitor. | 11-18-2010 |
20100301940 | NEGATIVE CAPACITANCE SYNTHESIS FOR USE WITH DIFFERENTIAL CIRCUITS - Provided herein are methods and circuits that reduce a differential capacitance at differential nodes of a differential circuit while boosting the common mode capacitance at the differential nodes, where the differential circuit includes a pair of inputs and differential outputs. A negative capacitance is generated between differential nodes of the differential circuit, which can be accomplished by connecting a negative capacitance circuit between the differential nodes of the differential circuit. In an embodiment, the negative capacitance circuit is connected in parallel with the differential outputs of the differential circuit. In another embodiment, the negative capacitance circuit is connected in parallel with the inputs of the differential circuit. In still another embodiment, the negative capacitance circuit is connected in parallel with the differential internal nodes (i.e., nodes other than the input and output nodes) of the differential circuit. | 12-02-2010 |
20100301941 | Receiver - Disclosed herein is a receiver, including: an amplifier for amplifying a received signal; a strain compensator for having a function of compensating for a strain generated in an output signal from the amplifier in accordance with a stain compensation amount which is controlled based on a bias signal from the output signal from the amplifier; and a stain compensation amount controlling portion for generating the bias signal and outputting the bias signal to the strain compensator so that the strain compensation is carried out with a compensation amount corresponding to a strength of the received signal. | 12-02-2010 |
20100315164 | Constant-Bandwidth Variable Gain Amplifier - The performance of an AGC loop typically depends on several factors, including gain linearity of the VGA and variation in the VGA bandwidth over the range of available gain settings. Although a resistively degenerated VGA provides for excellent gain linearity and immunity to process variations, the conventional architecture for a resistively degenerated VGA suffers from bandwidth variation over the range of available gain settings. Embodiments are provided herein of a constant-bandwidth VGA that utilizes resistive degeneration. To maintain a constant bandwidth over the range of available gain settings, degeneration resistors are coupled in parallel with compensation capacitors. In an embodiment, a compensation capacitor is determined to have a capacitance substantially equal to the decrease in total degeneration resistance that occurs as a result of an associated degeneration resistor being placed in parallel with the total degeneration resistance. | 12-16-2010 |
20110001562 | HIGH SPEED LINEAR DIFFERENTIAL AMPLIFIER - A high speed linear differential amplifier (HSLDA) having automatic gain adjustment to maximize linearity regardless of manufacturing process, changes in temperature, or swing width change of the input signal. The HSLDA comprises a differential amplifier, and a control signal generator including a replica differential amplifier, a reference voltage generator, and a comparator. The comparator outputs a control signal that automatically adjusts the gain of the high speed linear differential amplifier and of the replica differential amplifier. The replica differential amplifier receives predetermined complementary voltages as input signals and outputs a replica output signal to the comparator. The reference voltage generator outputs a voltage to the comparator at which linearity of the output signal of the differential amplifier is maximized. The control signal equalizes the voltage level of the replica output signal and the reference voltage, and controls the gain of the differential amplifier. | 01-06-2011 |
20110063030 | CMOS VARIABLE GAIN AMPLIFIER - A complementary metal-oxide semiconductor (CMOS) variable gain amplifier includes: a cascode amplifier including a common source field effect transistor and a common gate field effect transistor in a cascode structure; a first current generation unit connected in parallel to a drain of the common gate field effect transistor and configured to vary transconductance of the cascode amplifier; a second current generation unit connected to a common source of the cascode amplifier and configured to control a bias current of the cascode amplifier; a current control unit configured to generate a current control signal for the first and second current generation units; and a load stage connected in series to a drain of the cascode amplifier and configured to output an output current, which is varied by the overall transconductance of the cascode amplifier, as a differential output voltage. | 03-17-2011 |
20110063031 | DRIVING APPARATUS AND DRIVING METHOD THEREOF - A driving apparatus and a driving method thereof are provided. The driving apparatus includes a digital to analog converter and a signal amplifier. The digital to analog converter is used for receiving a digital data and converting the digital data to an analog signal. The signal amplifier is coupled to the digital to analog converter. The signal amplifier is used for receiving the analog signal to generate a driving signal. The signal amplifier also dynamically changes the driving ability of the driving signal according to at least one bit of the digital data. | 03-17-2011 |
20110084762 | Envelope Detector for High Speed Applications - An envelope detecting circuit is provided. The envelope detecting circuit comprises a source degeneration circuit that amplifies an input differential signal, a differential gain stage that supplies a voltage proportional to the amplified signal, a potential hold circuit that holds the voltage supplied from the gain stage, a comparator circuit that compares the voltage held by the potential holding circuit with a reference potential to output a detect signal, and envelope level adjustment and selection unit that responds to the detect signal and outputs a control signal to the source degeneration circuit. | 04-14-2011 |
20110084763 | DB-LINEAR PROCESS-INDEPENDENT VARIABLE GAIN AMPLIFIER - An amplifier is provided with continuously-variable analog control that exhibits a highly linear gain control curve in db/volts, while preserving high dynamic range, low third order distortion, and low noise. This amplifier has a control mechanism that preserves a varied linear or log linear curve over a wide range and is inherently insensitive to process variations thereby allowing more accurate gain control and higher signal fidelity for amplifying high dynamic range signals. | 04-14-2011 |
20110095822 | VARIABLE-GAIN LOW NOISE AMPLIFIER - A highly linear variable-gain low noise amplifier is a cascode amplifier. The cascode amplifier includes a gain control circuit, a load circuit, a current steering circuit and an input circuit. The gain control circuit is used for receiving a gain adjusting voltage, thereby generating a resistance adjusting signal and a current steering control signal. The load circuit includes plural variable resistors. The resistances of the variable resistors are adjusted according to the resistance adjusting signal. The current steering circuit is connected to the load circuit through plural current paths for adjusting a current ratio between the plural current paths according to the current steering control signal. The current steering circuit has differential signal output terminals. The input circuit is connected to the current steering circuit. The input circuit has differential signal input terminals. | 04-28-2011 |
20110095823 | INCREMENTAL GAIN AMPLIFIER - An amplifier includes an amplifier section having selectable signal paths to provide discrete gain settings, and logic to incrementally select the signal paths. The logic may be configured to increment the gain in response to digital gain control signals or an analog gain control signal. Another amplifier has an input section with one or more input cells and an output section with one or more output cells. Either the input section or the output section includes at least two cells that may be selected to provide discrete gain settings. A loop amplifier is configured in a feedback arrangement with the input section. The input and output sections may have multiple selectable cells to provide coarse and fine gain steps. The gain of the loop amplifier may be coordinated with the gain of the input section to provide constant bandwidth operation. | 04-28-2011 |
20110121900 | METHOD AND SYSTEM FOR IMPROVING LIMITING AMPLIFIER PHASE NOISE FOR LOW SLEW-RATE INPUT SIGNALS - Apparatus and method for a limiting amplifier with improved phase noise. The improved limiting amplifier includes an input port, an output port, and one or more cascaded gain stages. The input of a first gain stage is connected to the input port of the limiting amplifier. The output of a last gain stage is connected to the output port of the limiting amplifier. Among the cascaded gain stages, an output of each gain stage is connected to an input of an adjacent gain stage. Each gain stage i, 1 | 05-26-2011 |
20110121901 | Constant gain amplifier system with gain control feedback - Constant and accurate signal gain systems based on controlling signal amplifier gain level by applying the signal amplifier output signal to a signal level divider with a set ratio. The output signal of the signal level divider is applied to one input of the gain control amplifier, which is a differential amplifier, while the signal amplifier input signal is applied to the other input. The gain control amplifier output level is used to control the gain level of the signal amplifier. The gain control amplifier output level forces by negative feedback the gain control amplifier input levels to be substantially equal thus maintaining the signal amplifier gain level substantially constant. | 05-26-2011 |
20110133837 | VARIABLE GAIN AMPLIFIER - A gain variable range of a variable gain amplifier is increase and a non-linear distortion is reduced at the same time. The variable gain amplifier includes an operational amplifier, a variable resistive circuit which includes a plurality of variable resistive elements connected together in series, each having a resistance value corresponding to a given control voltage, and is connected between an input terminal and an output terminal of the operational amplifier, and a control circuit configured to generate a plurality of control voltages each corresponding to a gain control signal, having an offset corresponding to a DC voltage difference between input and output of the operational amplifier, and apply the plurality of control voltages to the plurality of the variable resistive elements, respectively. | 06-09-2011 |
20110148524 | RADIO FREQUENCY BUFFER - Systems, methods, and devices for receiving a differential input signal and generating a non-differential output signal are described herein. For example, an RF buffer is described that includes first and second transistor elements. The first transistor element receives a first polarity signal of a differential signal and drives a non-differential output of the RF buffer. A second transistor element receives a second polarity signal of the differential signal and drives the non-differential output of the RF buffer. The first and second transistor elements substantially simultaneously drive the non-differential output of the RF buffer. | 06-23-2011 |
20110181357 | GAIN CONTROL AMPLIFIER - Systems, methods, and devices provided herein are directed to improvements in gain control amplifiers that receive an input signal and generate an output signal with a selectively variable gain. A differential amplified gain stage receives an input signal and scales the input signal to generate a scaled signal. A gain adjust stage receives the scaled signal and an adjust signal and adjusts an amplitude of the scaled signal based on the adjust signal to generate an adjusted scaled signal. The adjusted scaled signal has a substantially constant impedance regardless of value of the adjust signal. | 07-28-2011 |
20110193632 | SEMICONDUCTOR INTEGRATED CIRCUIT DEVICE - Disclosed is a semiconductor integrated circuit device that includes a ring oscillator circuit, performs a proper oscillation operation, and expands the range of oscillation frequency variation. The ring oscillator circuit includes, for instance, plural differential amplifier circuits. MOS transistors are respectively added to input nodes of a differential pair of the differential amplifier circuits. Further, gate control circuits are incorporated to control the gates of the MOS transistors, respectively. The gate control circuits cause the MOS transistors to function as an amplitude limiter circuit in mode | 08-11-2011 |
20110210793 | VARIABLE GAIN AMPLIFIER HAVING AUTOMATIC POWER CONSUMPTION OPTIMIZATION - A variable gain amplifier may include a master amplifier that may be configured to generate a first current and a diode coupled with the master amplifier so that the first current passes through the diode which, when the first current is passing through the diode, generates a diode voltage signal. According to embodiments, an error amplifier may include a first input configured to receive a gain control voltage signal and a second input configured to receive the diode voltage signal. The output of the error amplifier may provide a feedback signal. The amplifier may include a circuit configured to generate at least one voltage control signal based on the feedback signal and a slave amplifier configured to adjust a gain amount based on the at least one voltage control signal. | 09-01-2011 |
20110227649 | APPARATUS AND METHOD FOR VARIABLE GAIN TRANSCONDUCTANCE - The present disclosure describes a variable gain transconductor having gain and/or linearity performance that are selectively controllable in operation. In one embodiment the gain and/or linearity performance are selectively controllable in response to the strength of an input signal, such as an incoming radio frequency (RF) signal to a radio receiver. In one embodiment, gain and/or linearity performance of the variable gain transconductor are selectively controllable by selecting or deselecting a number of operating bias cells. In one embodiment, gain and/or linearity performance of the variable gain transconductor are selectively controllable by selecting or deselecting a number of operating transconductance (gm) cells. In one embodiment, gain and/or linearity performance of the variable gain transconductor are selectively controllable by selecting or deselecting a combination of operating bias cells and gm cells. In one embodiment, the variable gain transconductor is configured to convert single-ended voltage input into a differential current output. In one embodiment, the variable gain transconductor is configured to convert differential voltage input into a differential current output. | 09-22-2011 |
20110227650 | RECEIVED-LIGHT AMPLIFYING CIRCUIT AND OPTICAL DISC APPARATUS - A received-light amplifying circuit includes: an amplifier AMP | 09-22-2011 |
20110227651 | PROGRAMMABLE GAIN AMPLIFIER AND TRANSCONDUCTANCE COMPENSATION SYSTEM - A programmable gain amplifier (PGA) system comprises selectable parallel transconductors in a front end, independently selectable serial amplification circuits in a back end. The back end is configured to receive an output of the front end and may include a plurality of current or voltage mode amplifiers in series. The PGA system also includes control circuitry to select a gain configuration for the PGA by selecting selectable components in the front and back ends. The PGA system may additionally include control circuitry configured to change the transconductance of one or more of the front end transconductors such that the gain configurations of the PGA are independent of variations such as those due to temperature and fabrication. The PGA system may be used between a signal receiver and an analog to digital converter. | 09-22-2011 |
20120001690 | System for Driver Amplifier - In an embodiment, a circuit includes a two-stage amplifier and a feedback component. The two stage amplifier consists of an input stage biased at a first power supply voltage, and an output stage biased at a second power supply voltage. The second power supply voltage is greater than the first power supply voltage, and the second stage is configured for high voltage operation. The feedback component is connected between the output stage to the input stage. | 01-05-2012 |
20120013404 | Method and Apparatus for Broadband Input Matching with Noise and Non-Linearity Cancellation in Power Amplifiers - A CMOS differential power amplifier having broadband input matching with Noise and Non-linearity Cancellation. The broadband input match is realized by using two “Diode-Connected” NFETs (i.e., N-type Field Effect Transistors). Resulting noise degradation is reduced by using a noise cancellation structure. By using the same structure the disclosed method and apparatus also achieves non-linearity cancellation. | 01-19-2012 |
20120025911 | Low Noise Amplifier with Current Bleeding Branch - An LNA circuit for providing a wide range of gain while maintaining the output headroom. In a radio frequency (RF) receiver, the signal received by the receiver may be extremely small. For a transmitter in a short distance, the received signal may be relatively strong. A low power amplifier usually is used to amplify the input signal. The LNA has to be designed to accommodate a wide range of gain. A convention LNA circuit supporting a wide range of gain often suffers from reduced output headroom due to increased current through the load resistor. The present invention discloses the use of current bleeding branch to allow a portion of current to flow through the current bleeding branch and consequently reduces the current that would have flown through the load resistor. Consequently, the voltage across the load resistor may be maintained low to allow adequate output headroom. | 02-02-2012 |
20120038422 | SYMMETRICALLY OPERATING SINGLE-ENDED INPUT BUFFER DEVICES AND METHODS - Embodiments are described including those pertaining to an input buffer having first and second complementary input terminals. One example buffer has a symmetrical response to a single input signal applied to the first input terminal by mimicking the transition of a signal applied to the second input terminal in the opposite direction. The buffer includes two amplifier circuits structured to be complementary with respect to each other. Each of the amplifier circuits includes a first transistor having a first input node that receives an input signal transitioning across a range of high and low voltage levels, and a second transistor having a second input node that receives a reference signal. The first input node is coupled to the second transistor through a capacitor to mimic the second input node transitioning in the direction opposite to the transition of the input signal. | 02-16-2012 |
20120086508 | CIRCUIT FOR THERMAL PROTECTION IN AUDIO POWER AMPLIFIER AND METHOD THEREOF - The present invention relates to audio amplifier and a method for protecting the audio amplifier. The audio amplifier includes a pre-amp circuit, an output stage power amplifier, a temperature detector and a gain adjusting circuit. The pre-amp circuit receives an audio signal for amplifying the audio signal to generate an amplified audio signal. The output stage power amplifier receives the amplified audio signal to drive a load. The temperature detector is used for detecting a temperature of the output stage power amplifier to output a temperature signal. The gain adjusting circuit adjusts amplitude of the amplified audio signal of the pre-amp circuit according to the temperature signal. | 04-12-2012 |
20120098597 | SWITCH FOR USE IN A PROGRAMMABLE GAIN AMPLIFIER - A switch circuit is provided. The switch circuit may include a first transistor having a source terminal to accept an input signal, a drain terminal to provide an output signal, and a gate; a power supply providing a gate voltage. The switch circuit may also include a circuit to couple a switch signal to the gate, wherein the circuit turns the first transistor ‘off’ for all values of the input signal when the switch signal is ‘low.’ A programmable gain amplifier (PGA) is also provided. The PGA may include an input stage having an input node to couple an input signal, and an output node to provide a gate signal, at least a first gain stage including a resistor and a switch circuit as above. A differential gain amplifier may be included to provide an output signal from the gain signal. | 04-26-2012 |
20120105156 | RECEIVER CIRCUIT OF SEMICONDUCTOR APPARATUS AND METHOD FOR RECEIVING SIGNAL - A receiver circuit of a semiconductor apparatus includes a first sense amplifier, a level restriction unit, and a second sense amplifier. The first sense amplifier amplifies an input signal in response to a clock signal and generates a first signal with a voltage swing between a first level and a second level. The level restriction unit receives the first signal and generates a correction signal with a voltage swing between the first level and a third level. The second sense amplifier amplifies the correction signal in response to the clock signal and generates a second signal with the voltage swing between the first level and the second level. | 05-03-2012 |
20120139633 | SEMICONDUCTOR INTEGRATED CIRCUIT AND TUNER SYSTEM INCLUDING THE SAME - A presented semiconductor integrated circuit, which processes an RF signal, achieves preferable distortion characteristics even at the low supply voltage. It includes an attenuator configured to attenuate an input signal with a variable attenuation, a source follower configured to receive an output of the attenuator, and an amplifying unit configured to perform a filtering process on an output of the source follower, and then amplify the output of the source follower with a variable gain. | 06-07-2012 |
20120146725 | GATED CLASS H AMPLIFIER/LINE DRIVER SYSTEM AND METHOD - Amplifier circuitry ( | 06-14-2012 |
20120154047 | LOW-NOISE AMPLIFIER - A low-noise amplifier comprises an input terminal to which a signal is input; a transistor configured to amplify the signal input to the input terminal; an output terminal through which the amplified signal from the transistor is output; a feedback amount regulator circuit configured to regulate an amplitude of the signal output from the transistor as a feedback amount and output a voltage; a bias circuit configured to generate a bias current fed to the transistor; a differential voltage comparator configured to compare the voltage output from the feedback amount regulator circuit to a reference voltage, determine whether or not a level of the signal input to the input terminal is a level at which a gain of the transistor is suppressed, and increase the bias current fed to the transistor when the differential voltage comparator determines that the level of the signal input to the input terminal is the level at which the gain of the transistor is suppressed; a first input bias circuit configured to generate the reference voltage and apply the reference voltage to one input end of the differential voltage comparator; and a second input bias circuit configured to add a bias voltage to the voltage output from the feedback amount regulator circuit and apply the voltage added with the bias voltage to the other input end of the differential voltage comparator. | 06-21-2012 |
20120188014 | ADAPTIVE SIGNAL EQUALIZER WITH SEGMENTED COARSE AND FINE CONTROLS - Circuitry for adaptive signal equalizing with coarse and fine boost controls by providing multiple serially coupled stages of parallel controllable DC and AC signal gains with coarse and fine gain controls provided across all stages. | 07-26-2012 |
20120206201 | SEMICONDUCTOR DEVICE - A variable gain amplifier circuit includes output nodes, a plurality of amplifiers, and a detection circuit. The amplifiers are coupled in parallel with each other between the output nodes and a reference node and selectively assume an operating state in accordance with a control signal. The detection circuit outputs a detection signal according to the magnitude of an input signal to each amplifier. Each amplifier includes a first transistor, a second transistor, and a bias circuit. The first transistor receives, at its control electrode, the input signal or a signal proportional to the input signal. The second transistor is series-coupled to the first transistor between the first reference node and an output node. The bias circuit applies a DC voltage of a magnitude according to the detection signal to a control electrode of the second transistor. | 08-16-2012 |
20120206202 | GAIN ENHANCEMENT CIRCUIT AND METHOD - In accordance with an embodiment, a gain enhancement circuit includes an amplifier having an input terminal, a transistor coupled to the input terminal and a capacitance dynamically coupled to another input terminal of the amplifier by a switch, wherein the capacitance is a parasitic element of the transistor. | 08-16-2012 |
20120235745 | VARIABLE GAIN AMPLIFIER - An apparatus and method are provided. Generally, an input signal is applied across a main path (through an input network) and across a cancellation path (through a cancellation circuit). The cancellation circuit subtracts a cancellation current from the main path as part of the control mechanism, where the magnitude of the cancellation current is based on a gain control signal (that has been linearized to follow a control voltage). | 09-20-2012 |
20120242408 | LOW NOISE VARIABLE GAIN AMPLIFIER UTILIZING VARIABLE FEEDBACK TECHNIQUES WITH CONSTANT INPUT/OUTPUT IMPEDANCE - Variable feedback architecture and control techniques for variable gain amplifiers (VGAs) concurrently maintain, across a wide range of VGA gain settings, minimal input and output impedance variations, a low noise figure, low rates of change in noise figure, high signal-to-noise ratio (SNR), high quality of service (QoS), low distortion, high and relatively constant output third order intercept point (i.e., IP3 or TOI). Variable feedback counteracts impedance variations caused by gain variations. Compared to conventional high performance VGAs, noise figure is lower (e.g. 3 dB lower at maximum gain and 12 dB lower at minimum gain) and relatively constant, IP3 is higher and relatively constant, small signal third order intermodulation signal (IM3) tone slope is relatively constant and input and output impedances are relatively constant. As gain decreases, the noise figure advantage is nearly dB per dB compared to conventional high performance VGAs. | 09-27-2012 |
20120268206 | NEGATIVE CAPACITANCE SYNTHESIS FOR USE WITH DIFFERENTIAL CIRCUITS - Provided herein are methods and circuits that reduce a differential capacitance at differential nodes of a differential circuit while boosting the common mode capacitance at the differential nodes, where the differential circuit includes a pair of inputs and differential outputs. A negative capacitance is generated between differential nodes of the differential circuit, which can be accomplished by connecting a negative capacitance circuit between the differential nodes of the differential circuit. In an embodiment, the negative capacitance circuit is connected in parallel with the differential outputs of the differential circuit. In another embodiment, the negative capacitance circuit is connected in parallel with the inputs of the differential circuit. In still another embodiment, the negative capacitance circuit is connected in parallel with the differential internal nodes (i.e., nodes other than the input and output nodes) of the differential circuit. | 10-25-2012 |
20120286870 | INTEGRATED CIRCUIT OF AN INTEGRATOR WITH ENHANCED STABILITY AND RELATED STABILIZATION METHOD - An integrated circuit integrator includes a first transconductance amplifier having a gain adjustable based upon a first control signal, and receives, as an input, a signal to be filtered, and generates, as an output, a corresponding amplified signal. The first transconductance amplifier includes an R-C output circuit to filter components from the amplified signal, and an output resistance being adjustable based upon a second control signal. A second transconductance amplifier is matched with the first transconductance amplifier, and has a gain adjustable based upon the first control signal, and a matched output resistance adjustable based upon the second control signal. A circuit is configured to force a reference current through the matched output resistance. An error correction circuit is coupled to the second transconductance amplifier and is configured to generate the second control signal so as to keep constant a voltage on an output of the second transconductance amplifier. | 11-15-2012 |
20120326787 | VARIABLE-GAIN AMPLIFIER CIRCCUIT AND RECEIVER INCLUDING THE SAME - A variable-gain amplifier (VGA) circuit comprises a plurality of cascaded VGAs each having a gain that varies linearly according to a gain control voltage. The VGA circuit has an overall gain that varies exponentially according to the gain control voltage without the use of an exponential function generator circuit. | 12-27-2012 |
20130021098 | INTEGRATOR DISTORTION CORRECTION CIRCUIT - A system and method for reducing gain error and distortion in an operational amplifier due to errors in the second or integrator stage. A correction circuit may replicate an error current and insert the current into the signal stream to preempt the induction of an error at the amplifier's input. A capacitor may sample the error voltage at the input of the integrator stage of the amplifier and generate a replica of the error current in the integration capacitor to feed it into the input of the integrator stage. This eliminates any nonlinearity errors created by error currents in the compensation or integration capacitor at the second or integrator stage of the two-stage amplifier. Feeding the error current to the integrator stage may be facilitated with a unity gain buffer and a current mirror. | 01-24-2013 |
20130021099 | VRAMP LIMITING USING RESISTORS - Power amplification devices are described, which are configured to amplify a radio frequency (RF) transmission signal. The power amplification device includes a voltage regulation circuit and a power amplification circuit. The voltage regulation circuit includes a voltage regulator that is operable to generate a regulated voltage from the supply voltage and a feedback circuit that sets a voltage adjustment gain of the voltage regulation circuit. To help prevent the voltage regulation circuit from saturating, the feedback circuit reduces the voltage adjustment gain in response to a voltage difference reaching a threshold voltage level. The voltage difference is between a voltage regulator control signal level of a voltage regulator control signal and the regulated voltage level of the regulated voltage. This configuration can be utilized to reduce a drop-out voltage level of the voltage regulator and get better performance despite supply voltage degradation and variations in operational conditions, such as temperature. | 01-24-2013 |
20130021100 | Method and System for Multiple Tuner Application Using a Low Noise Broadband Distribution Amplifier - An active splitter circuit arrangement includes a first amplification module having a number of first input ports and first output ports. The first amplification module is configured to provide first stage amplification to a received input signal and produce from the amplified input signal a number of output signals, each substantially matching the input signal. Also included is a first gain control device configured to control a gain of the first amplification module. Next, a number of second amplification modules corresponding to the number of output signals has a number of second input ports respectively coupled to the first output ports. Each second amplification module is configured to receive a control signal from the second gain control device, provide second stage amplification to a corresponding one of the number of output signals based upon the control signal and produce an amplified output signal. | 01-24-2013 |
20130027133 | SENSE AMPLIFIERS INCLUDING BIAS CIRCUITS - Sense amplifiers including bias circuits are described. Examples include bias circuits having an adjustable width transistor. A loop gain of the bias circuit may be determined in part by the adjustable width of the transistor. Examples of sense amplifiers including amplifier stages configured to bias an input/output node to a reference voltage. | 01-31-2013 |
20130027134 | SWITCHING REGULATOR WITH VARIABLE COMPENSATION - A switching regulator circuit includes a power stage and a compensation network. The compensation network includes a programmable transconductance (g | 01-31-2013 |
20130043948 | SEMICONDUCTOR DEVICE FOR SIGNAL AMPLIFICATION - A semiconductor device for transmitting-signal amplification which has a fine resolution, a high dynamic range, a small occupied area, and low power consumption, is realized. An input signal amplitude is reduced every one half by a ladder network, and a transconductance amplifier stage is arranged corresponding to each node of the ladder network. An output of the transconductance amplifier stage is coupled to an output signal line in common. According to a control word WC<21:0>, the transconductance amplifier stage is enabled selectively, and the output current which appears in the output signal line is added. | 02-21-2013 |
20130057346 | APPARATUS AND METHOD FOR LOW NOISE AMPLIFICATION - Embodiments provide an amplifier and a method for using and manufacturing said amplifier that incorporate an impedance matching stage, a feedback circuit, and a gain stage. The impedance matching stage is coupled to the feedback circuit wherein the feedback circuit provides a compensated second bias voltage for the impedance matching stage. The output of the impedance matching stage is used to set an input bias voltage for both the impedance matching stage and the gain stage. The output of the impedance matching stage is also used, together with the output of the gain stage, to produce an output of the amplifier. A signal reuse stage may be provided between the output of the impedance matching stage and the output of the amplifier. | 03-07-2013 |
20130057347 | AMPLIFIERS USING GATED DIODES - A circuit comprises a control line and a two terminal semiconductor device having a first terminal is coupled to a signal line, and a second terminal is coupled to the control line. The semiconductor device has a capacitance when a voltage on the first terminal is above a threshold and has a smaller capacitance when a voltage on the first terminal is below the threshold. A signal is placed on the signal line and a voltage on the control line is modified. When the signal falls below the threshold, the semiconductor device acts as a very small capacitor and the output will be a small value. When the signal is above the threshold, the semiconductor device acts as a large capacitor and the output will be influenced by the signal and the modified voltage on the control line and the signal is amplified. | 03-07-2013 |
20130082776 | AMPLIFIER FOR RECEIVING OPTICAL SIGNALS COMPLEMENTARY TO EACH OTHER - An amplifier for detecting photocurrents complementary to each other is disclosed. The optical receiver includes two trans-impedance amplifiers (TIAs) each having the single phase arrangement, a level detector to detect an average level between respective outputs of the TIAs, a controller to detect a difference between each of the output of the TIA, and an offset canceller to bypass each of the photocurrents to compensate the output offset between two TIAs depending on the average level and the difference between two levels. | 04-04-2013 |
20130106513 | DIFFERENTIAL AMPLIFIER | 05-02-2013 |
20130113566 | VARIABLE GAIN AMPLIFIER - An apparatus and method are provided. Generally, an input signal is applied across a main path (through an input network) and across a cancellation path (through a cancellation circuit). The cancellation circuit subtracts a cancellation current from the main path as part of the control mechanism, where the magnitude of the cancellation current is based on a gain control signal (that has been linearized to follow a control voltage). | 05-09-2013 |
20130127533 | OPERATIONAL AMPLIFIER HAVING LOW POWER CONSUMPTION - The present invention relates to an operational amplifier having low power consumption, which comprises a differential circuit, an output-stage circuit, and a floating bias generating circuit. The differential circuit receives an input signal and produces a control signal. The output-stage circuit is coupled to the differential circuit and produces an output signal according to the control signal. The floating bias generating circuit is coupled between the differential circuit and the output-stage circuit and generates a floating bias according to the control signal for controlling the rising or lowering of the voltage level of the output signal. Accordingly, the operational amplifier can charge and discharge rapidly, and thus extending the applications of the operational amplifier. Besides, the floating bias generating circuit can limit the output current while the operational amplifier is driving, and thus achieving the purpose of low power consumption. | 05-23-2013 |
20130127534 | VARIABLE PHASE AMPLIFIER CIRCUIT AND METHOD OF USE - A variable phase amplifier circuit is disclosed and its method of use in tuning devices having resonators. The variable phase amplifier receives an input differential signal pair. The input differential signal pair can be generated by a resonator device. The variable phase amplifier generates a modified differential signal pair in response to receiving the input differential signal pair. The variable phase amplifier provides a means to vary the phase of the modified differential signal pair with respect to the input differential signal pair, in an accurate and stable manner. If the modified differential signal pair with a phase shift introduced in it is fed back to the resonator device, the resonator will change its frequency of oscillation, where the new frequency of oscillation is a function of the phase of the modified differential signal pair. | 05-23-2013 |
20130127535 | Method and System for Optoelectronic Receivers for Uncoded Data - A method and system for optoelectronic receivers for uncoded data are disclosed and may include amplifying received electrical signals in a signal amplifier comprising differential gain stages with signal detectors coupled to the outputs. First and second output voltages may be tracked and held utilizing the signal detectors. A difference between the tracked and held value may be amplified in a feedback path of the gain stage, which enables the dynamic configuration of a decision level. The received electrical signals may be generated from an optical signal by a PIN detector, an avalanche photodiode, or a phototransistor. The electrical signal may be received from a read channel. The feedback path may comprise digital circuitry, including an A/D converter, a state machine, and a D/A converter. The detectors may comprise envelope detectors utilized to detect maximum or minimum voltages. The signal amplifier may be integrated in a photonically-enabled CMOS chip. | 05-23-2013 |
20130135049 | INCREMENTAL GAIN AMPLIFIER - An amplifier includes an amplifier section having selectable signal paths to provide discrete gain settings, and logic to incrementally select the signal paths. The logic may be configured to increment the gain in response to digital gain control signals or an analog gain control signal. Another amplifier has an input section with one or more input cells and an output section with one or more output cells. Either the input section or the output section includes at least two cells that may be selected to provide discrete gain settings. A loop amplifier is configured in a feedback arrangement with the input section. The input and output sections may have multiple selectable cells to provide coarse and fine gain steps. The gain of the loop amplifier may be coordinated with the gain of the input section to provide constant bandwidth operation. | 05-30-2013 |
20130147557 | VARIABLE GAIN AMPLIFIER CIRCUIT - A variable gain amplifier circuit is disclosed. The variable gain amplifier circuit includes a first transistor, a second transistor, a third transistor, a fourth transistor, a first gain switching circuit, and a second gain switching circuit. The first and the second transistors are respectively coupled to the first and the second nodes for receiving a differential input signal pair. The third transistor is coupled between the first node and a third node. The fourth transistor is coupled between the second node and a fourth node. The first gain switching circuit is coupled between the first node and the third node and further cross-coupled to the fourth node. The second gain switching circuit is coupled between the second node and the fourth node and further cross-coupled to the third node. | 06-13-2013 |
20130154738 | AMPLIFIER AND FILTER HAVING VARIABLE GAIN AND CUTOFF FREQUENCY CONTROLLED LOGARITHMICALLY ACCORDING TO DIGITAL CODE - A variable gain amplifier circuit is provided. The circuit includes an operational amplifier for amplifying and outputting an input signal according to a cutoff frequency and a gain, a feedback resistor for changing a first resistance according to a first digital control code value which determines the cutoff frequency, and an input resistor for changing a second resistance according to a second digital control code value which is determined based on a difference of the first digital control code value and a gain code value. The gain is determined by a ratio of the first resistance and the second resistance and linearly changes on a decibel (dB) basis according to the first digital control code value, the cutoff frequency is inversely proportional to the first resistance and linearly changes on a log scale, and the variable gain can be easily set using the control code. | 06-20-2013 |
20130229231 | DIFFERENTIAL CIRCUIT COMPENSATING GAIN ENHANCEMENT DUE TO SELF HEATING OF TRANSISTORS - A differential circuit with a function to compensate the gain enhancement due to the self-heating of the transistor is disclosed. The differential circuit includes an equalizer unit coupled with one of paired transistors. The other of the paired transistor receives the input signal to be amplified. The base level, or the base-emitter bias, is oppositely modulated by the input signal through the common emitter, which causes the modification of the base current. The equalizer unit reduces the variation of the base level only in low frequencies where the self-heating effect of the transistor appears. | 09-05-2013 |
20130241652 | UTILIZING A SENSE AMPLIFIER TO SELECT A SUITABLE CIRCUIT - Embodiments of the present invention provide an approach for utilizing a sense amplifier to select a suitable circuit, wherein a suitable circuit generates a voltage that is greater than or equal to a configurable reference voltage. An amplifier gain selector selects a voltage gain of a sense amplifier having input terminals, auxiliary inputs, an output, an array of resistive loads, and the amplifier gain selector. Auxiliary inputs are utilized to nullify direct current (DC) offset voltage of the sense amplifier. Combinatorial logic circuitry connects the input terminals of the sense amplifier to output terminals of a circuit that is within a group of circuits. A comparator circuit determines if the circuit generates a voltage greater than or equal to a configurable reference voltage, based on the output of the sense amplifier. | 09-19-2013 |
20130241653 | INSTRUMENTATION INPUT SYSTEMS - A variable gain amplifier has an attenuator having an input and a series of tap points, and a series of low-inertia switches, each switch coupled to a corresponding one of the tap points to steer outputs from the attenuator to an output terminal. An amplifier has an input cell, a load coupled to an output of the input cell, a buffer having an input coupled to the load, a feedback network coupled between an output of the buffer and the input cell, and a variable filter cell coupled to the input cell. | 09-19-2013 |
20130249634 | POWER AMPLIFIER WITH AN ADAPTIVE BIAS - An electronic circuit, including, a power amplifier adapted to amplify an RF signal and provide it as output from the integrated circuit; a power source that is adapted to provide an unregulated voltage to the power amplifier; a regulator adapted to provide a regulated bias voltage; a subtracter that is adapted to accept a voltage proportional to the unregulated voltage and subtract it from the bias voltage to provide a reference voltage to the power amplifier; wherein the power amplifier is adapted to use the reference voltage to adjust the output from the power amplifier so that it will provide a stable power output. | 09-26-2013 |
20130271216 | High Side Current Sense Amplifier - A single stage current sense amplifier is described that generates a differential output that is proportional to a current through a sense resistor. The voltage across the sense resistor is Vsense. The current sense amplifier includes a differential transconductance amplifier having high impedance input terminals. An on-chip RC filter filters transients in the Vsense signal. A feedback circuit for each leg of the amplifier causes a pair of input transistors to conduct a fixed constant current irrespective of Vsense, which stabilizes the transconductance. A gain control resistor (Re) is coupled across terminals of the pair of input transistors and has Vsense across it. The current through the gain control resistor is therefore Vsensex1/Re. A level shifting circuit coupled to each of the input transistors lowers a common mode voltage at an output of the amplifier. Chopper circuits at the input and output cancel any offset voltages. | 10-17-2013 |
20130278337 | DIFFERENTIAL SIGNAL CORRECTION CIRCUIT - A differential signal correction circuit is disclosed. The differential signal correction circuit may comprise a first single-ended-to-differential converter and a second single-ended-to-differential converter. Each one of the two converters may comprise an input port and two output ports. The converters may be configured to perform a first phase correction for a pair of differential signals and output a first output signal and a second output signal. The first output signal is fed back to the first converter through one of the output ports of the first converter, and the second output signal is fed back to the second converter through one of the output ports of the second converter so as to perform phase correction and amplitude correction for the first output signal and the second output signal. | 10-24-2013 |
20130300502 | VARIABLE-GAIN LOW NOISE AMPLIFIER - The present disclosure relates to variable-gain low noise amplifiers and RF receivers. An exemplary method for processing a RF signal provides a low noise amplifier with main and auxiliary amplifier modules. When a selection indicates the low noise amplifier operating in a high-gain mode, the main and auxiliary amplifier modules are coupled in parallel. When the selection indicates the low noise amplifier operating in a low-gain mode, the main and auxiliary amplifier modules are cross coupled. When a selection indicates the low noise amplifier operating in a moderate-gain mode, the auxiliary amplifier modules are disconnected from the main amplifier module. | 11-14-2013 |
20130300503 | PROGRAMMABLE-GAIN AMPLIFIER - An integrated circuit (IC) includes a programmable gain amplifier. The programmable gain amplifier comprises a first-stage amplifier configured to operate with at least one relatively high power supply voltage in order to accommodate at the input of the first-stage amplifier a relatively large range of input signals, the first-stage amplifier having a gain setting that is adjustable from a set of predetermined gain settings separated in relatively coarse increments so as to minimize the number of analog switches that must be implemented with high-voltage active devices in order to set each gain setting. The programmable gain amplifier also includes a second-stage amplifier configured to operate with at least one relatively low power supply voltage, lower than the high power supply voltage in order to minimize the required IC area for the second-stage amplifier, wherein the gain of the second-stage amplifier is adjustable from a set of gain settings separated in relatively small increments between the coarse increments in order to achieve a combined predetermined gain resolution. The gain of the programmable gain amplifier is programmable by adjusting the gain of each of the first-stage and second-stage amplifiers. | 11-14-2013 |
20130307620 | SIGNAL AMPLIFYING CIRCUIT WITH REDUCED OUTPUT SIGNAL NOISE BY INTRODUCING COUPLING EFFECT AND RELATED METHOD THEREOF - A signal amplifying circuit includes: an input stage circuit, arranged to receive an input signal; a first inductive device coupled between the input stage circuit and a first reference voltage; an output stage circuit arranged to generate an output signal according to the input signal; and a second inductive device coupled between the output stage circuit and a second reference voltage, wherein at least a part of a winding of the first inductive element is cross-coupled to at least a part of a winding of the second inductive element. | 11-21-2013 |
20130307621 | VRAMP LIMITING USING RESISTORS - Power amplification devices are described, which are configured to amplify a radio frequency (RF) transmission signal. The power amplification device includes a voltage regulation circuit and a power amplification circuit. The voltage regulation circuit is configured to generate a regulated voltage for the power amplification device from a supply voltage and to adjust a regulated voltage level of the regulated voltage in accordance with a voltage adjustment gain. The voltage adjustment gain of the voltage regulation circuit is set by a feedback resistance. To help prevent the voltage regulation circuit from saturating, the voltage regulation circuit adjusts the feedback resistance to reduce the voltage regulation gain. | 11-21-2013 |
20130314156 | Variable Gain Amplifier - A method may include applying an input differential voltage to input terminals of an amplifier, a first input terminal coupled to a gate of a first transistor and a second input terminal coupled to a gate of a second transistor. The method may also include varying a gain of the amplifier by varying at least one of: a resistance of a first resistor, the first resistor coupled between a source of the first transistor and a source of the second transistor; and a resistance of a second resistor, the second resistor coupled between a source of a third transistor and a source of a fourth transistor; wherein: the third transistor is coupled at its drain to the drain of the first transistor; and the fourth transistor is coupled at its drain to the drain of the second transistor and a gate of the third transistor and coupled at its gate to the drain of the third transistor. | 11-28-2013 |
20130314157 | VARIABLE GAIN AMPLIFIER - The embodiments of the present invention disclose a variable gain amplifier and relate to the field of electronic circuits. The linear-in-dB relationship between an output current and a control voltage of the variable gain amplifier is relatively ideal. The variable gain amplifier includes a fitted differential module group and an offset voltage output module, where the fitted differential module group is configured to output, under the control of a driving voltage and offset voltages, an output current of the variable gain amplifier according to a reference current; and the fitted differential module group includes n fitted differential modules, the n fitted differential modules are cascaded in turn, and n is any positive integer larger than 1. | 11-28-2013 |
20130314158 | SEMICONDUCTOR DEVICE AND COMMUNICATION DEVICE - A semiconductor device capable of achieving high speed performance in addition to correction of differential offset and a communication device provided with the semiconductor device are provided. For example, there are provided: a variable gain type differential amplifier circuit VGA | 11-28-2013 |
20130328630 | POWER AMPLIFIER - A power amplifier is provided. The power amplifier includes a loading circuit, a first stage amplifying circuit, an analog pre-distorter, a loading circuit and a second stage amplifying circuit. The first stage amplifying circuit is coupled to the loading circuit to receive a first signal and output a second signal accordingly. The analog pre-distorter is coupled to the first stage amplifying circuit to detect the envelope of the second signal and generates a third signal according to the envelope. The second stage amplifying circuit is coupled to the first stage amplifying circuit to receive the second signal. The loading circuit is biased on the third signal. The gain of the first stage amplifying circuit is related to the third signal. | 12-12-2013 |
20130342274 | DC-COUPLED PEAK DETECTOR - Techniques are disclosed relating to peak detection. In one embodiment, an apparatus is disclosed that includes an amplifier configured to amplify a signal. The apparatus further includes a peak detector DC coupled to an output of the amplifier. The peak detector includes a first comparator stage configured to perform subtraction of a threshold signal from the amplified signal. The peak detector further includes a second comparator stage is configured to amplify a differential output signal of the first comparator stage indicative of a result of the subtraction. In some embodiments, the amplifier and peak detector are included within automatic gain control system in a path for an in-phase or quadrature channel of the receiver chain. | 12-26-2013 |
20130342275 | TRANSIMPEDANCE AMPLIFIER - Provided is a transimpedance amplifier which can realize a high-speed and high-quality receiver operation in an optical communication module or a router device having the optical communication module. An offset voltage which is generated in a post amplifier for differentiating and amplifying a single-phase output signal from a pre-amplifier in accordance with single-phase differentiation and conversion is cancelled by detecting a threshold voltage from an output of the pre-amplifier or an output of the post amplifier by a threshold detection circuit and by shifting a level of the threshold voltage corresponding to an offset amount to be compensated. | 12-26-2013 |
20140002194 | Variable Gain Amplifier for Low Voltage Applications | 01-02-2014 |
20140015607 | LOW NOISE AMPLIFIERS FOR MULTIPLE RADIO STANDARDS - Low noise amplifiers and related control methods for multiple radio standards are disclosed. An exemplary low noise amplifier comprises input ports, an output port, amplifier stages, and a degeneration inductor. Each amplifier has a gain stage and a buffer stage connected in series. The buffer stage selectively channels an output of the gain stage to the output port or a power supply. The degeneration inductor is commonly connected to the gain stage in each of the amplifier stages. | 01-16-2014 |
20140049319 | AMPLIFICATION CIRCUIT AND RECEPTION CHAIN - An amplification circuit including: an input for receiving an input voltage; an output for exhibiting an output voltage; a primary amplifier configured to receive the input voltage from the input, receive a primary control voltage, first amplify the input voltage by a primary gain dependent on the control voltage, the output voltage corresponding to the first amplified input voltage, and supply the output voltage to the output; and a secondary amplifier configured to receive the input voltage from the input, second amplify the input voltage by a secondary gain, the primary control voltage corresponding to the second amplified input voltage, and supply the primary control voltage to the primary amplifier. The secondary amplifier has in operation an input admittance of at least 1 millisiemens. | 02-20-2014 |
20140077878 | FOLDED-CASCODE AMPLIFIER - An amplifier with gain boosting is disclosed according to an aspect of the subject technology. The gain boosting may be used to improve the noise figure of the amplifier, and may be achieved by feeding an input signal to the gates of multiple transistors in the amplifier, where each transistor provides a current gain contributing to the total current gain of the amplifier. The amplifier may also include an output driver stage for increasing the driving capability of the amplifier. The amplifier may also include a feedback resistor and an input resistor to obtain a gain with high linearity. | 03-20-2014 |
20140103998 | RADIO FREQUENCY SIGNAL GAIN CONTROL - An RE receiver is described comprising a common gate common source LNA with a variable resistor in the source of the common gate transistor, a variable resistor in the source of the common source transistor, and a variable resistor in the RE input. A Smart Gain Control varies the resistance in the resistors to produce linear amplification in the LNA while maintaining input matching. Further, a broad dynamic range RSSI is described that implements a feedback control loop to maintain signal power within a sensitivity range of the power detector in the RSSI. | 04-17-2014 |
20140118067 | AUTOMATIC GAIN CONTROL ELECTRONIC CIRCUIT WITH DUAL SLOPE FOR AN AMPLIFIER - The electronic circuit is arranged for the fast, automatic gain control of an input amplifier. It includes a non-linear amplifier-comparator for comparing a reference signal (V | 05-01-2014 |
20140139288 | ADJUSTABLE GAIN FOR MULTI-STACKED AMPLIFIERS - Techniques for providing adjustable gain in an amplifier. In an aspect, a composite amplifier having adjustable gain includes a plurality of amplifiers coupled in parallel, wherein each of the amplifiers may be turned on or off to adjust the overall gain of the composite amplifier. Each amplifier may include an input transistor and at least two cascode transistors. To turn each amplifier off, the gate voltage of a second or lowermost cascode transistor coupled to the input transistor may be grounded, and the gate voltage of a first cascode transistor coupled to the output voltage may be coupled to a first turn-off voltage to reduce the drain-to-gate voltage drop across the first cascode transistor. Further aspects provide for decoupling a capacitor coupled to the gates of the cascode transistors from AC ground when the amplifier is turned off | 05-22-2014 |
20140145790 | METHOD AND APPARATUS FOR IMPLEMENTING A LOW NOISE AMPLIFIER WITH ASSOCIATED GAIN AND INPUT IMPEDANCE - An apparatus with associated gain and input impedance includes gain devices, a switching unit and a resistor. A first differential pair of gain devices and associated bias circuitry is configured to operate in a full gain mode. A second differential pair of gain devices is configured to operate in a reduced gain mode. The switching unit is configured to disable the first differential pair of gain devices and enable the second differential pair of gain devices in the reduced gain mode and to disable the second differential pair of gain devices and enable the first differential pair of gain devices in the full gain mode. The resistor is configured to maintain constant input impedance of the apparatus when in the reduced gain mode. | 05-29-2014 |
20140167848 | SENSE AMPLIFIER HAVING LOOP GAIN CONTROL - Memories, sense amplifiers, and methods for amplifying a current input are disclosed, including a sense amplifier including a bias circuit configured to provide a bias voltage having a magnitude responsive to maintaining a substantially constant loop gain, and further including an amplifier stage coupled to the bias circuit to receive the bias voltage and configured to amplify a input current at an input-output node, a loop gain of the current amplifier stage is controlled at least in part to the bias voltage. | 06-19-2014 |
20140176238 | DC OFFSET CANCELLATION FOR A MULTI-STAGE AMPLIFIER - This invention provides a multi-stage amplifier incorporating DC offset cancellation. The amplifier has a plurality of series-connected gain stages each of which comprises a differential amplifier unit generating a pair of differential outputs from a pair of differential inputs. In particular, a trailing stage in the plurality of gain stages comprises a digital DC offset cancellation module configured to compensate for a DC offset of the trailing stage's differential amplifier unit. The digital DC offset cancellation module comprises a comparator coupled to the pair of differential outputs of the trailing stage's differential amplifier unit for receiving such differential outputs as inputs for the comparator. Preferably, the comparator has an inherent DC offset that is substantially small. It is preferable that a non-trailing stage of the amplifier comprises an analog DC offset cancellation module for compensating for a DC offset of the non-trailing stage. | 06-26-2014 |
20140184329 | CURRENT CANCELING GAIN CONTROL FOR HIGH FREQUENCY WIDEBAND CROSS-COUPLED AMPLIFIERS - An embodiment of the present invention provides a configuration of a cross-coupled common-source differential amplifier stage which enables performing a gain step down (attenuation) while maintaining good step flatness over a large relative bandwidth. | 07-03-2014 |
20140184330 | TIME GAIN COMPENSATION - In certain embodiments, circuits and methods for time gain compensation are provided. A circuit includes a first op-amp that is configured to compare a first and a second input voltage signal received from first and second input circuits, respectively, and output a first op-amp output signal. A control circuit coupled with a first semiconductor element of the second input circuit is configured to vary a first resistance value of the first semiconductor element to control the first op-amp output signal. The first op-amp output signal includes a relatively high voltage signal and a relative low voltage signal when an input control voltage signal corresponds to a first reference voltage and a second reference voltage signal, respectively associated with the first op-amp. The first op-amp output signal is input to a gate terminal of a load semiconductor element so-as to vary an impedance of the load semiconductor element. | 07-03-2014 |
20140191803 | CONTINUOUS VARIABLE GAIN AMPLIFIER - A continuous variable gain amplifier includes an attenuator network, a boost network, a first amplifying network, and a second amplifying network, where the attenuator network generates first differential output signals according to an input signal and sends the first differential output signals to the first amplifying network and the second amplifying network; the first amplifying network and the second amplifying network receive one output of the first differential output signals each, and generate a first final output signal and a second final output signal respectively according to an externally input control voltage; and the boost network receives the first final output signal and the second final output signal, generates second differential output signals, and sends a first output and a second output of the second differential output signals to the first amplifying network and the second amplifying network, respectively | 07-10-2014 |
20140203873 | SIGNAL PROCESSING APPARATUS AND METHOD - A signal processing apparatus and method are disclosed. A common mode signal extraction unit is configured to extract a common mode signal from input signals inputted to a differential amplifier. A common mode signal adjustment unit is configured to adjust a gain and a phase of the common mode signal and to output the adjusted common mode signal to the differential amplifier. An optimal set determination unit is configured to determine an optimal gain and phase to be applied to the common mode signal based on an output signal from the differential amplifier. | 07-24-2014 |
20140218112 | Compensation Circuitry And Method For Amplifiers Driving Large Capacitive Loads - An operational amplifier ( | 08-07-2014 |
20140218113 | DYNAMIC FEED-FORWARD OPAMP-BASED CIRCUIT - A dynamic feed-forward OPAMP-based circuit is provided. A first amplifying stage amplifies a pair of input differential signals to provide a pair of intermediate differential signals. A second amplifying stage amplifies the pair of intermediate differential signals to provide a pair of output differential signals. A first capacitor is coupled to a non-inverting input terminal of the first amplifying stage. A second capacitor is coupled to an inverting input terminal of the first amplifying stage. A feed-forward transconductance stage is coupled between the first and second capacitors and the second amplifying stage. The first and second capacitors and the feed-forward stage form a high-frequency path with a first gain curve, and the first amplifying stage and the second amplifying stage form a high-gain path with a second gain curve. The operational amplifier provides an open-loop gain according to the first and second gain curves. | 08-07-2014 |
20140253235 | VARIABLE GAIN AMPLIFIER - According to an embodiment, a variable gain amplifier includes a differential transistor pair including a first and second transistor. A variable resistor for setting a gain is connected between electrodes the transistor pair. A first variable capacitor is connected to an electrode of the first transistor, and a second variable capacitor is connected to an electrode of the second transistor. Corresponding to the gain setting set by adjusting the variable resistor, capacitance values of the variable capacitors can be adjusted to provide improved frequency characteristics of the variable gain amplifier. | 09-11-2014 |
20140266439 | METHODS AND SYSTEMS TO PROVIDE LOW NOISE AMPLIFICATION - An amplifier, including a voltage-to-current converter (V2I) to control an output current based on an input voltage, resistive degeneration circuitry to reduce baseband gain of the voltage-to-current converter, capacitive degeneration circuitry to increase passband gain of the voltage-to-current converter, and impedance control circuitry to compensate for negative input impedance of the capacitive degeneration circuitry. The V2I may include series-connected complimentary V2Is. The impedance control circuitry may include resistive negative feedback to provide a real part of input impedance, which may increase a frequency range for which the amplifier is linear. Capacitive degeneration and associated phase compensation may increase a frequency range for which the resistive feedback is negative. The amplifier may be configured as a single-input/single-output system and/or as a differential system. | 09-18-2014 |
20140266440 | OFFSET CANCELLATION WITH MINIMUM NOISE IMPACT AND GAIN-BANDWIDTH DEGRADATION - A system for cancelling offset includes a gain circuit. The gain circuit may include a transistor circuit connected to a pair of input nodes and configured to convert an input signal to an output signal so that the output signal has a gain compared with the input signal. The gain circuit also may include a pair of output nodes configured to receive the output signal from the transistor circuit. The gain circuit is configured to cause a voltage change at one of the output nodes relative to another output node, in response to the gain circuit receiving a feedback offset correction signal. This effectively cancels at least a portion of an offset in the output signal | 09-18-2014 |
20140266441 | THREE STAGE AMPLIFIER - A cascaded amplifier including a pre-amplifier stage having a pair of first transistors, each of the first transistors having a first gate terminal coupled to a first input voltage, a trans-conductive (gm) amplifier stage having a pair of second transistors, each of the second transistors having a second gate terminal coupled to a drain terminal of one of the first transistors, and an integrator amplifier stage having a pair of third transistors, each of the third transistors having a third gate terminal coupled to a drain node of one of the second transistors, each of the third transistors having their drain terminals coupled to an output voltage. | 09-18-2014 |
20140266442 | VOLTAGE CONTROLLED AMPLIFIER AND METHOD OF USING THE SAME - A simplified VCA circuit is presented. The VCA of the present invention uses fewer components and is less complex than prior art OTA-based VCAs. Further, the VCA of the present invention has improved total harmonic distortion (THD) and DC offset characteristics as compared to prior art VCAs. The VCA may be used to prevent clipping with the addition of clipping detection circuitry. | 09-18-2014 |
20140320207 | LOW NOISE VARIABLE GAIN AMPLIFIER UTILIZING VARIABLE FEEDBACK TECHNIQUES WITH CONSTANT INPUT/OUTPUT IMPEDANCE - Variable feedback architecture and control techniques for variable gain amplifiers (VGAs) concurrently maintain, across a wide range of VGA gain settings, minimal input and output impedance variations, a low noise figure, low rates of change in noise figure, high signal-to-noise ratio (SNR), high quality of service (QoS), low distortion, high and relatively constant output third order intercept point (i.e., IP3 or TOI). Variable feedback counteracts impedance variations caused by gain variations. Compared to conventional high performance VGAs, noise figure is lower (e.g. 3 dB lower at maximum gain and 12 dB lower at minimum gain) and relatively constant, IP3 is higher and relatively constant, small signal third order intermodulation signal (IM3) tone slope is relatively constant and input and output impedances are relatively constant. As gain decreases, the noise figure advantage is nearly dB per dB compared to conventional high performance VGAs. | 10-30-2014 |
20140333381 | APPARATUS AND METHODS FOR BUFFER LINEARIZATION - Apparatus and methods for buffer linearization are provided. In certain implementations, an amplifier includes a buffer circuit and a gain circuit. The buffer circuit includes a buffer transistor pair used to buffer a differential input signal to generate a differential buffered signal. Additionally, the gain circuit includes a gain transistor pair configured to amplify the buffered differential signal to generate an amplified differential signal. The buffer circuit can include a linearization transistor pair configured to decrease the buffer circuit's output impedance and to provide feedback that reduces changes in the voltage of the differential buffered signal in response to displacement currents associated with the C | 11-13-2014 |
20140340146 | VARIABLE-GAIN DUAL-OUTPUT TRANSCONDUCTANCE AMPLIFIER-BASED INSTRUMENTATION AMPLIFIERS - A variable-gain current conveyor-based instrumentation amplifier without introducing distortion. An exemplary variable-gain instrumentation amplifier includes a first dual-output transconductance amplifier (DOTA) (i.e., current conveyor) that receives a first input voltage, a second DOTA that receives a second input voltage, a first resistive element connected between the first and second DOTA, an amplifier connected to the second DOTA at an inverting input, and a second resistive element that connects the second DOTA and the inverting input to an output of the amplifier. At least one of the resistive elements is a variable resistive element. | 11-20-2014 |
20140340147 | AMPLIFIER CIRCUIT AND AMPLIFICATION METHOD - A true ground amplifier circuit in which a voltage sensor senses the output voltage and generates a binary output which indicates whether the output is above or below a threshold. A variable gain feedback system generates a feedback signal for combination with the digital input, thereby to provide offset cancellation. The variable gain is reduced over time to provide offset cancellation during an initial period of time of operation of the amplifier circuit. This provides offset cancellation during a start-up period, for example. | 11-20-2014 |
20140340148 | Variable Gain Amplifier - A method may include applying an input differential voltage to input terminals of an amplifier, a first input terminal coupled to a gate of a first transistor and a second input terminal coupled to a gate of a second transistor. The method may also include varying a gain of the amplifier by varying at least one of: a resistance of a first resistor, the first resistor coupled between a source of the first transistor and a source of the second transistor; and a resistance of a second resistor, the second resistor coupled between a source of a third transistor and a source of a fourth transistor; wherein: the third transistor is coupled at its drain to the drain of the first transistor; and the fourth transistor is coupled at its drain to the drain of the second transistor and a gate of the third transistor and coupled at its gate to the drain of the third transistor. | 11-20-2014 |
20140368269 | Current Divider Based Voltage Controlled Gain Amplifier - An RF amplifier includes an input stage, a buffer stage, and an output stage. The input stage is configured to provide attenuation and impedance matching for an input radio frequency (RF) signal by providing shunt and series variable resistance current paths and RF power to RF current conversion. The input stage routes the RF current between the current paths resulting in an attenuation of the RF input current. The buffer stage is configured to provide an intermediate RF current which tracks the current level of the attenuated RF input current, thereby providing isolation between the input and output stages. The output stage is configured to provide RF current to RF power conversion, utilizing the intermediate RF current to provide an RF signal having an RF output power proportional to the RF input power. | 12-18-2014 |
20150015331 | Method and Circuit for Controlled Gain Reduction of a Differential Pair - The present document relates to multi-stage amplifiers, such as linear regulators or linear voltage regulators (e.g. low-dropout regulators) configured to provide a constant output voltage subject to load transients. A multi-stage amplifier is described, having a differential amplification stage which comprises a differential transistor pair. The differential amplification stage is configured to provide a stage output voltage at a stage output node of the differential transistor pair, based on a first input voltage at a first stage input node and a second input voltage at a second stage input node. The differential transistor pair also comprises a reference node. The differential amplification stage further comprises an active load comprising a first diode transistor coupled to the reference node and a first mirror transistor coupled to the stage output node. | 01-15-2015 |
20150015332 | Method and Circuit for Controlled Gain Reduction of a Gain Stage - The present document relates to multi-stage amplifiers, such as linear regulators or linear voltage regulators (e.g. low-dropout regulators) configured to provide a constant output voltage subject to load transients. A multi-stage amplifier is described. The multi-stage amplifier comprises a first amplification stage configured to provide a stage output voltage at a stage output node. Furthermore, the amplifier comprises an intermediate amplification stage comprising an amplifier current source configured to provide an amplifier current and an amplifier transistor arranged in series with the amplifier current source. A gate of the amplifier transistor is coupled to the stage output node of the first amplification stage. The intermediate amplification stage is configured to provide an amplified or attenuated stage output voltage at a midpoint between the amplifier current source and the amplifier transistor. | 01-15-2015 |
20150028952 | PROGRAMMABLE MULTI-GAIN CURRENT AMPLIFIER - The programmable multi-gain current amplifier circuitry includes a pair of MOS transistors setting the voltage at X terminal to zero using negative feedback formed by a third MOS transistor. Input resistance is in the range of few tens of ohms. The input current i | 01-29-2015 |
20150048885 | GAIN CONTROL CIRCUIT AND METHOD CAPABLE OF EASING LEAKAGE CURRENT INFLUENCE - The present invention discloses a gain control circuit capable of easing leakage current influence. According to an embodiment of the present invention, the gain control circuit comprises: at least one signal input end for receiving at least one input signal; a signal output end for outputting an output signal; an amplifier coupled between an amplifier input end and the signal output end; and a plurality of gain schemes. Each of the gain schemes is set between the at least one signal input end and the signal output end; and when one of the gain schemes is activated to generate the output signal, the rest gain schemes are inactivated to stop gain production and concurrently discharge leakage currents through their respective grounding paths. | 02-19-2015 |
20150061764 | ANALOG AMPLIFIER FOR RECOVERING ABNORMAL OPERATION OF COMMON MODE FEEDBACK - An analog amplifier for recovering an abnormal operation of a common-mode feedback is provided. An analog variable amplifier includes a first input transistor and a second input transistor, a first output transistor and a second output transistor, a third transistor and a fourth transistor, a first current source, a fifth transistor and a sixth transistor, and a second current source. The first input transistor and the second input transistor amplify a bias current depending on a magnitude of a first input voltage and a second input voltage. The first output transistor and the second output transistor output the amplified bias current. The third transistor and the fourth transistor receive an output voltage of the first output transistor as an input and amplifying the received output voltage. The first current source provides a predetermined current between the first output transistor and the third transistor. | 03-05-2015 |
20150061765 | GAIN CALIBRATION OF A HIGH SPEED AMPLIFIER - Embodiments include systems and methods for accurately controlling gain of a high-speed variable-gain amplifier (VGA) without adversely impacting bandwidth performance. Embodiments include a VGA with a variable resistor, for which resistance is a function of a control level. A gain calibration system controls the control level by using a gain control feedback subsystem to sample outputs of a duplicate VGA, which includes a duplicate variable resistor. The sampled duplicate outputs are compared to a target gain generated by a reference generator. The control level can be fed back to control the gain of the duplicate VGA until the target gain is reached. The control level can also be fed to the actual VGA to control its gain. By performing gain control on the duplicate VGA without interfering with the output signal path of the actual VGA, the actual VGA's gain can be accurately controlled without impacting its bandwidth. | 03-05-2015 |
20150061766 | WIDEBAND INDUCTOR-LESS BALUN-LNA WITH IMPROVED PICKUP NOISE REJECTION - An inductor-less balun low-noise amplifier (LNA) includes a cross-coupled network coupled between first and second input terminals and first and second summing nodes. The cross-coupled network may include: a first non-inverting gain stage coupled between the first input terminal and the first summing node; a first inverting gain stage coupled between the first input terminal and the second summing node; a second non-inverting gain stage coupled between the second input terminal and the second summing node; and a second inverting gain stage coupled between the second input terminal and the first summing node. The cross coupled network may be configurable to provide common-mode rejection when operated in a differential or in a single-ended mode of operation. | 03-05-2015 |
20150070091 | ANALOG AMPLIFIERS AND COMPARATORS - An innovative analog circuit design using digital components is disclosed. Embodiments of the present invention includes, but not limited to analog amplifiers and comparators. An amplifier of an embodiment of the present invention includes an inverter, a plurality of switches, offset capacitor and flying capacitor. The one terminal of the offset capacitor is connected to the input of the inverter. During setup phase of clock signals, the switches are configured to connect input and output of the inverter and to connect the flying capacitor to input terminals of the amplifier, respectively, for storing a differential input voltage. Then, during the enable phase of the clock signals, the switches are configured to connect the first terminal of the second capacitor and the first terminal of the first capacitor, and to connect the second terminal of the second capacitor to the output of the inverter. | 03-12-2015 |
20150077183 | CURRENT-FEEDBACK OPERATIONAL AMPLIFIER - An integrated, fully-differential current-feedback transimpedance operational amplifier circuit is disclosed. The circuit can be configured as a class-AB, low-impedance input stage, followed by an inverter-based, rail-to-rail output stage. For enhancing the open-loop transimpedance gain of the amplifier without consuming additional DC power, the same bias current is used both in the input stage and in a gain-enhancement stage serving as its load. The gain-enhancement stage can be either DC- or AC-coupled to the input of the amplifier. In the case of DC coupling, an output common-mode feedback loop can be used to provide the proper operating voltages in the amplifier. | 03-19-2015 |
20150084693 | PROGRAMMABLE-GAIN INSTRUMENTATION AMPLIFIER - A device comprises a first amplifier, a first resistive element that comprises a first resistor and a first dummy switch, a second amplifier, a second resistive element that comprises a second resistor and a second dummy switch, and a programmable resistive gain element operable to receive control input, wherein a resistance value of the programmable resistive gain element is based at least in part on the received control input, wherein a first end of the programmable resistive gain element is connected to both the first inverting input of the first amplifier and to a second end of the first dummy switch, and wherein a second end of the programmable resistive gain element is connected to both the second inverting input of the second amplifier and to a second end of the second dummy switch. | 03-26-2015 |
20150097622 | AMPLIFIER CIRCUIT - An amplifier circuit has: a main amplifier connected between an input terminal and an output terminal, the main amplifier amplifying an input signal input to the input terminal and outputting an amplified signal to the output terminal; a compensation circuit comprising a variable delay circuit and a variable gain inverting circuit, the variable delay circuit receiving the input signal and outputting a delay signal with a delay time from the input signal, the variable gain inverting amplifier inverting and amplifying the delay signal with a gain and outputting a compensation signal to the output terminal; and a controller configured to control the gain of the pre-emphasis circuit and the delay time of the variable delay circuit to compensate a response of the main amplifier in a first frequency band lower than a base frequency of a target signal of compensation and in a low frequency band higher than zero Hertz. | 04-09-2015 |
20150109057 | RESISTIVE LADDER - A resistive ladder has first, second and third resistors coupled in series between first and second voltage terminals. A first node of the first resistor is coupled to the first voltage terminal and a first node of the third resistor is coupled to the second voltage terminal. A voltage selection unit has a first input coupled to a first node of the second resistor and a second input coupled to a second node of the second resistor and is adapted to selectively couple one of the first and second inputs to an output node of said resistive ladder. The resistive ladder also includes a first switch coupled between a second node of the third resistor and the second voltage terminal. | 04-23-2015 |
20150116035 | DIGITAL CALIBRATION OF PROGRAMMABLE GAIN AMPLIFIERS - A programmable gain amplifier (PGA) includes an op amp, an input circuit, a feedback circuit, and a calibration circuit. The input circuit is connected between a PGA input node and an op-amp input node and selectively applies the analog input signal to the op-amp input node. The feedback circuit is connected between an op-amp output node and the op-amp input node and applies the amplified analog output signal as a feedback signal to the op-amp input node. The calibration circuit is connected between a calibration reference node and the op-amp input node and selectively connects the calibration reference node directly to the op-amp input node without traversing any of the input circuit. The PGA may be implemented as a single-ended or differential amplifier. The PGA avoids reduced linearity resulting from series combinations of switches in the input circuit when configured for its normal operating mode. | 04-30-2015 |
20150130537 | POWER AMPLIFICATION MODULE - Disclosed is a power amplification module which has a comparatively small size and is capable of adjusting the rising characteristic of a gain. The power amplification module includes a first gain control current generation circuit which generates a first gain control current changing with a control voltage, a first bias current generation circuit which generates a first bias current according to the first gain control current, a gain control voltage generation circuit which generates a gain control voltage changing with the control voltage, a first transistor which is emitter-grounded and in which an input signal and the first bias current are supplied to a base thereof, and a second transistor which is cascode-connected to the first transistor and in which the gain control voltage is supplied to a base thereof and a first output signal obtained by amplifying the input signal is output from a collector thereof. | 05-14-2015 |
20150303887 | BROADBAND MICROWAVE VARIABLE GAIN UP-CONVERTER - A system has a baseband gain stage to receive incoming in-phase and quadrature voltage signals and output in-phase and quadrature current signals, a mixer core arranged to receive the in-phase and quadrature current signals and output radio frequency signals, and a variable gain amplifier to receive the radio frequency signals and produce a broadband radio signal. | 10-22-2015 |
20150326197 | PROGRAMMABLE GAIN AMPLIFIER WITH CONTROLLED GAIN STEPS - Provided is a programmable gain amplifier that includes controlled gain steps that dynamically control an output voltage in real-time. The programmable gain amplifier includes a first transistor and a second transistor that includes respective control ports, input ports, and output ports. The programmable gain amplifier also includes a resistor connected to the output ports of the transistors. Further, at least a third transistor is connected to the output ports, in parallel with the resistor. On applying a control voltage to the third transistor and applying an input voltage to the first control port, the second control port is selectively modified by the control voltage to produce a desired output at the first input port and the second input port | 11-12-2015 |
20150341003 | DIFFERENTIAL CURRENT AMPLIFIER - A current amplifier is disclosed. The circuit has differential input and output and can be implemented in CMOS or bipolar integrated-circuit technologies. The input current is injected into a pair of primary branches, and is re-used at the output of the circuit without changing its natural flow, thus contributing to the overall current gain. A pair of secondary branches is connected to the primary branches in such a way as to provide currents proportional to the input currents according to a scaling factor dictated by the geometry of the transistors. The outputs of the secondary branches are cross-coupled relative to the outputs of the primary branches, in this way ensuring maximum current gain by the summing of the primary and secondary signal currents at the circuit output, without consuming additional DC power. | 11-26-2015 |
20150357983 | FIXED GAIN AMPLIFIER CIRCUIT - An instrumentation amplifier includes first and second resistors for gain setting. The operational amplifiers within the instrumentation amplifier include selectively enabled current drive sources coupled to the amplifier output. The first and second resistors have variable resistances. A control circuit is configured to select the variable resistances of the first and second resistors to implement a fixed gain for the instrumentation amplifier and further selectively enable the current drive sources. The control circuit receives an indication of a downstream programmable gain (for example, from a downstream programmable gain amplifier). The variable resistances of the first and second resistors are selected to be scaled inversely with respect to the downstream programmable gain and the current drive sources are enabled proportionately with respect to the downstream programmable gain. | 12-10-2015 |
20150381115 | EMPHASIS CIRCUIT - Provided is an emphasis circuit capable of obtaining a desired emphasis amount with which waveform deterioration of an output signal in a high frequency band (high frequency band deterioration) is suppressed without increasing power consumption (current consumption). In the emphasis circuit, a baseband amplifier section and a peaking amplifier section are connected in parallel to each other, and respective drive current setting sections are adjusted to adjust respective drive current values thereof so that the sum of the drive current value of the baseband amplifier section and the drive current value of the peaking amplifier section may be constant. | 12-31-2015 |
20150381129 | VARIABLE GAIN TRANSIMPEDANCE AMPLIFIER - Embodiments of variable gain transimpedance amplifiers are described. In an embodiment, the variable gain transimpedance amplifier may include an amplifier coupled to an adjustable gain feedback network, the adjustable gain feedback network including a selectable set of Resistor-Capacitor (RC) branches, each RC branch having one or more unit RC elements, each unit RC element being comprised of a unit resistor and a unit capacitor arranged in parallel. | 12-31-2015 |
20160056783 | RESONATING DEVICE WITH SINGLE OPERATIONAL AMPLIFIER - A resonating device includes: an amplifying circuit having a first input terminal, and an output terminal for outputting an output signal; a first feedback circuit coupled between the first input terminal and the output terminal of the amplifying circuit; a second feedback circuit, coupled between the first input terminal and the output terminal of the amplifying circuit; and a gain adjusting circuit, having an input terminal for receiving an input signal, and a first output terminal coupled to the first input terminal of the amplifying circuit; wherein a first equivalent impedance on a first intermediate terminal in the first feedback circuit substantially equals a second equivalent impedance on a second intermediate terminal in the second feedback circuit, and the gain adjusting circuit is arranged to tune a transfer function from the input signal to the output signal. | 02-25-2016 |
20160065157 | METHOD AND APPARATUS FOR GAIN ENHANCEMENT OF DIFFERENTIAL AMPLIFIER - A differential amplifier circuit and method having a feed-in network coupling an input signal to an intermediate signal. An amplifier amplifies the intermediate signal by a gain factor to output an output signal to a load network. A feedback network configured in a negative feedback topology and couples the output signal to the intermediate signal. A gain enhancing network is configured in a positive feedback topology and couples the output signal to the intermediate signal. Preferably, an impedance of the gain enhancing network is approximately equal to an impedance of a parallel connection of the feed-in network and the feedback network times the gain factor minus one. | 03-03-2016 |
20160094193 | SELECTABLE PROGRAMMABLE GAIN OR OPERATIONAL AMPLIFIER - An integrated circuit amplifier configurable to be either a programmable gain amplifier or an operational amplifier comprises two output blocks, one output block is optimized for programmable gain amplifier operation, and the other output block is optimized for operational amplifier applications. A common single input stage, input offset calibration and bias generation circuits are used with either amplifier configuration. Thus duplication of the input stage, offset calibration and bias generation circuits are eliminated while still selectably providing for either a programmable gain amplifier or operational amplifier configuration. | 03-31-2016 |
20160094195 | VOLTAGE-TO-CURRENT CONVERTER - A converter including: an amplifier having first and second input terminals and an output terminal, the first input terminal configured to receive a reference voltage; an array of resistors configured to generate a tuning voltage; and a first plurality of switches coupled to the second input terminal of the amplifier and the array of resistors, the first plurality of switches configured to adjust a gain of the amplifier by selecting at least one resistor in the array of resistors to connect to the second input terminal of the amplifier. | 03-31-2016 |
20160099694 | WIDE RANGE TRANSIMPEDANCE AMPLIFIER - One aspect of this disclosure is a transimpedance amplifier circuit with multiple resistive feedback loops can be implemented with multiple Kelvin sensing channels. A transimpedance amplifier and multiple Kelvin sensing channels can be implemented on a single die having multiple contacts, such as pins, for connecting multiple resistors to the Kelvin sensing channels. The Kelvin sensing channels can be implemented with T-junction switch networks in certain embodiments. | 04-07-2016 |
20160099696 | FIXED GAIN AMPLIFIER CIRCUIT - An instrumentation amplifier includes first and second resistors for gain setting. The operational amplifiers within the instrumentation amplifier include selectively enabled current drive sources coupled to the amplifier output. The first and second resistors have variable resistances. A control circuit is configured to select the variable resistances of the first and second resistors to implement a fixed gain for the instrumentation amplifier and further selectively enable the current drive sources. The control circuit receives an indication of a downstream programmable gain (for example, from a downstream programmable gain amplifier). The variable resistances of the first and second resistors are selected to be scaled inversely with respect to the downstream programmable gain and the current drive sources are enabled proportionately with respect to the downstream programmable gain. | 04-07-2016 |
20160118970 | PEAK DETECTOR USING CHARGE PUMP AND BURST-MODE TRANSIMPEDANCE AMPLIFIER - A peak detector using a charge pump is provided. The peak detector includes a differential amplifier configured to receive an input signal to be detected through an input node and amplify the received signal; a current control logic configured to create two or more current control signals by comparing a signal output from the differential amplifier with two or more reference voltages; a mirror current source portion comprising two or more mirror current sources configured to be driven respectively by the current control signals from the current control logic; a capacitor configured to be charged or discharged by currents output from the mirror current sources; and a reset circuit configured to reset a voltage of the capacitor. | 04-28-2016 |
20160149548 | TRANS-IMPEDANCE AMPLIFIER WITH REPLICA GAIN CONTROL - This disclosure relates to the field of amplifiers for multi-level optical communication and more particularly to techniques for trans-impedance amplifiers (TIA) with gain control. The claimed embodiments address the problem of implementing a low cost TIA that exhibits high linearity, low noise, low power, and wide bandwidth. More specifically, some claims are directed to approaches for providing TIA gain control using a plurality of inverter-based replica gain control cells controlled by a feedback loop to manage the current into the amplifying output stage and thereby the TIA output voltage. | 05-26-2016 |
20160204749 | METHODS AND APPARATUS FOR CALIBRATING FOR TRANSCONDUCTANCE OR GAIN OVER PROCESS OR CONDITION VARIATIONS IN DIFFERENTIAL CIRCUITS | 07-14-2016 |
20180026596 | Selectable Programmable Gain Or Operational Amplifier | 01-25-2018 |
20190149111 | AMPLIFIER WITH CONSTANT VOLTAGE GAIN | 05-16-2019 |