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Having gain control means

Subclass of:

330 - Amplifiers

330250000 - WITH SEMICONDUCTOR AMPLIFYING DEVICE (E.G., TRANSISTOR)

330252000 - Including differential amplifier

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DocumentTitleDate
20130043948SEMICONDUCTOR 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
20130027134SWITCHING REGULATOR WITH VARIABLE COMPENSATION - A switching regulator circuit includes a power stage and a compensation network. The compensation network includes a programmable transconductance (g01-31-2013
20100156535INTEGRATED 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
20100156534GAIN 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
20090058524RECEIVED 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
20100013557Current-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
20130027133SENSE 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
20110193632SEMICONDUCTOR 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
20130082776AMPLIFIER 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
20100007419Instrumentation 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
20090195310LNA 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
20080258814VARIABLE 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
20090302948POST 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
20090302947SEMICONDUCTOR 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
20090302946VARIABLE 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 V12-10-2009
20130057347AMPLIFIERS 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
20130057346APPARATUS 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
20090091387SWITCHED-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
20090267692DIGITALLY 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
20090261903VARIABLE 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
20100007418INPUT 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
20090009245Circuit 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
20120235745VARIABLE 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
20130021098INTEGRATOR 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
20110095823INCREMENTAL 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
20120105156RECEIVER 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
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
20100090765Programmable 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
20110133837VARIABLE 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
20120268206NEGATIVE 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
20120086508CIRCUIT 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
20090153245VARIABLE-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
20100123520Low 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
20080265991Gain 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
20110063031DRIVING 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
20090284316AMPLIFIER 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
20090102559MONOTONIC 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
20080303592Differential 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
20080211579METHOD 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
20090051429HIGH 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
20090128239Multistage 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
20090160554AMPLIFIER 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
20090079500ANALOG 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
20090140809High 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 C06-04-2009
20120139633SEMICONDUCTOR 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
20090140810Variable 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
20090140808GAIN 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
20090051428AGC 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 Vref02-26-2009
20090051430Variable 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 function02-26-2009
20090085660AGC 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
20090085661METHODS 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
20110227651PROGRAMMABLE 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
20110227650RECEIVED-LIGHT AMPLIFYING CIRCUIT AND OPTICAL DISC APPARATUS - A received-light amplifying circuit includes: an amplifier AMP09-22-2011
20110227649APPARATUS 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
20090231041Commutating 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
20090009246ELECTRONIC 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
20090108935Variable 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
20090256636Amplifier 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
20090256635LINEAR-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
20100001798DIGITALLY 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
20090079501PROGRAMMABLE 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
20100237943Auto 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
20090273401Method 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
20090278601Preamplifier 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
20090072905VARIABLE 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
20090072904Variable 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
20130135049INCREMENTAL 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
20100301941Receiver - 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
20100301940NEGATIVE 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
20110001562HIGH 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
20120242408LOW 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
20110210793VARIABLE 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
20110084762Envelope 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
20090153246Method 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
20110095822VARIABLE-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
20100194478EQUALIZER 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
20110148524RADIO 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
20090015331CURRENT 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
20120146725GATED CLASS H AMPLIFIER/LINE DRIVER SYSTEM AND METHOD - Amplifier circuitry (06-14-2012
20110084763DB-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
20120038422SYMMETRICALLY 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
20110063030CMOS 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
20120001690System 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
20120206202GAIN 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
20120013404Method 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
20120206201SEMICONDUCTOR 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
20120025911Low 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
20120154047LOW-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
20080265992Transconductance 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
20100289583VARIABLE 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
20110181357GAIN 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
20100052786AUTOMATIC 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
20100283543Variable 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
20120188014ADAPTIVE 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
20110121901Constant 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
20110121900METHOD 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, 105-26-2011
20080297250INTEGRATED 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
20080297251DIGITALLY 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
20120326787VARIABLE-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
20120286870INTEGRATED 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
20130021099VRAMP 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
20130021100Method 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
20080224775Variable 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
20130113566VARIABLE 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
20130127534VARIABLE 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
20130127535Method 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
20130127533OPERATIONAL 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
20130147557VARIABLE 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
20100315164Constant-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
20130154738AMPLIFIER 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
20100073090CURRENT 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
20090072903Variable 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

Patent applications in class Having gain control means