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Active filter

Subclass of:

327 - Miscellaneous active electrical nonlinear devices, circuits, and systems

327524000 - SPECIFIC IDENTIFIABLE DEVICE, CIRCUIT, OR SYSTEM

327551000 - Unwanted signal suppression

Patent class list (only not empty are listed)

Deeper subclasses:

Class / Patent application numberDescriptionNumber of patent applications / Date published
327553000 Adjustable 79
327557000 Bandpass 15
327558000 Lowpass 12
327559000 Highpass 5
20130043938LOW VOLTAGE ANALOG SWITCH - A switch for an analog signal may include a main MOS transistor whose source forms an input terminal of the switch and whose drain forms an output terminal of the switch, a capacitor having a first terminal permanently connected to the source of the main transistor, a circuit for charging the capacitor, and a first auxiliary transistor configured to connect the second terminal of the capacitor to the gate of the main transistor in response to a control signal. The charge circuit may include a resistor permanently connecting the second terminal of the capacitor to a power supply line. The capacitor and the resistor may form a high-pass filter having a cutoff frequency lower than the frequency of the analog signal.02-21-2013
20090121786SEMICONDUCTOR INTEGRATED CIRCUIT - A semiconductor integrated circuit can include a first voltage pad, a second voltage pad, and a voltage stabilizing unit that is connected between the first voltage pad and the second voltage pad. The first voltage pad can be connected to a first internal circuit, and the second voltage pad can be connected to a second internal circuit.05-14-2009
20080278229Active Compensation Filter - An active compensation filter for the application in the electric power supply in a land vehicle, which comprises a high-pass filter which is to be coupled with a supply voltage line which carries a supply voltage, in order to detect frequency and amplitude of interference voltage components of the supply voltage. A signal amplifier which is connected in series with the high-pass filter amplifies the detected interference voltage components and supplies them to a coupling element as output signals, which is connected in series with the signal amplifier and comprises a primary side and a secondary side. The primary side is fed with the output signals of the signal amplifier and the secondary side is looped into the supply voltage line.11-13-2008
20090058518HIGH-PASS FILTER - A capacitor has one end receiving an input signal and the other end outputting an output signal. A resistor circuit, connected between a power source and the other end of the capacitor, functions as a resistor. The resistor circuit includes a PNP transistor having a base connected to the other end of the capacitor and an NPN transistor having a base connected to the other end of the capacitor. A differential amplifier supplies complementary current to the PNP transistor and the NPN transistor. The differential amplifier receives, as negative feedback, the output signal from the other end of the differential amplifier.03-05-2009
20080297241APPLICATION-SPECIFIC INTEGRATED CIRCUIT WITH AUTOMATIC TIME-CONSTANT MATCHING - An application-specific integrated circuit (CS) comprises a first analog stage (E12-04-2008
327556000 Notch or bandreject 4
20100164612System and Method for Filtering Electrophysiological Signals - An acquired signal indicative of electrophysiological activity is filtered using both a wavelet filter and either a notch filter or a band-pass filter to eliminate noise or interference, such as power line interference. A wavelet transform is used to transform the acquired signal into the wavelet domain, where a wavelet filter is applied to extract a soft component (e.g., a component with small wavelet coefficients). A filter, such as a notch filter or a band-pass filter, is applied to the soft component in order to isolate an interference signal. The interference signal is used to produce an output signal representing the acquired signal filtered to eliminate the interference signal. For example, the interference signal may be subtracted from the acquired signal. Alternatively, the output signal may be reconstructed from respective hard and soft components of the acquired signal as transformed into the wavelet domain.07-01-2010
20100117724FILTER CIRCUIT - A plurality of low-pass filters (05-13-2010
20090096517Filtering apparatus and method for dual-band sensing circuit - A filtering apparatus and method for dual-band sensing circuit are disclosed. The invention features a dual-band sensing unit disposed in a filtering device that receives the signals from a sub-system with variable frequency spectrum. The signals are split up into several bands. After that, one or more frequency detecting units are used to detect the power of high-band and low-band signals, and convert the power into a voltage signal. Users can externally adjust the gain of a tunable gain amplifier for the voltage signal. Further, a comparison operation is processed by a comparator, and a signal resulted from the comparison operation is used to control the switch timing for an RF switching unit. Consequently, this like adaptive notch filter is achieved to determine the intensity of noise and thereby to turn on the high-band or low-band notch filters, so as to reduce the in-band loss.04-16-2009
20080224764Switched capacitor notch filter circuits - Switched capacitor notch filter circuits are disclosed. An example switched capacitor notch filter circuit described herein includes a switched capacitor amplifier to receive an input signal and a first feedback signal, to amplify the input signal and the first feedback signal, and to output an output signal, a first integrator to receive the output signal and a second feedback signal, to integrate the output signal and the second feedback signal, and to output the first feedback signal, a second integrator to receive the first feedback signal, to integrate the first feedback signal, and to output the second feedback signal, a sample and hold to receive the output signal, to periodically store a value of the output signal, and to output the value of the output signal, and a first switch to couple the sample and hold to the output signal when the sample and hold is to store the value of the output signal and to isolate the sample and hold from the output signal when the sample and hold is to output the value of the output signal.09-18-2008
Entries
DocumentTitleDate
20090195304TRANSADMITTANCE AND FILTER HAVING A GAIN FUNCTION - Disclosed are a circuit and a method for tuning a programmable filter including input terminals, output terminals, a filter network and a transadmittance stage. The input terminals can receive input signals, and the output terminals output a filtered signal. The transadmittance stage, coupled to the input terminals, generates a current at its output based on the input signals. The output of the transadmittance stage can be coupled to the output terminals. The filter network can be a resistive-capacitive network connected to the input terminals. The RC network can include a capacitance respectively coupling the input terminals to output terminals, and a voltage divider network coupling the input and output terminals together. The transadmittance stage output terminals can be connected to the voltage divider, and the output terminals of the programmable filter circuit are coupled to respective intermediate nodes of the voltage divider network to provide a filtered output signal.08-06-2009
20100156524PULSE FILTERING MODULE CIRCUIT, SYSTEM, AND METHOD - A filtering module filters out high frequency signals, primarily noise, from an input data stream. The filtering module includes an input module, a phase detecting module, and a threshold module. The input module performs either a charging or a discharging across a capacitor on a basis of an RC time constant. The phase detecting module is coupled to the input module to keep identical phase at a first node and an output node. The threshold module is coupled to the phase detecting module for providing an output signal based on a threshold voltage and the charging or the discharging across the capacitor.06-24-2010
20100060348BANDWIDTH-ADJUSTABLE FILTER - A bandwidth-adjustable filter includes an operational amplifier, a first resistor, a first capacitor and a first resistor ladder circuit. The operational amplifier has a negative input terminal and a positive input terminal The first resistor is coupled to one of the input terminals of the operational amplifier. The first capacitor is coupled to the first resistor. The first resistor ladder circuit is coupled in parallel to the first resistor for changing the resistance of the first resistor so as to adjust the bandwidth of the filter. 03-11-2010
20090322418DISCRETE TIME MULTI-RATE ANALOG FILTER - A discrete time analog filter suitable for use in a receiver and other electronics devices is described herein. In one exemplary design, an apparatus may include a transconductance amplifier, a sampler, and a discrete time analog filter. The transconductance amplifier may amplify a voltage input signal and provide an analog signal. The sampler may sample the analog signal and provide analog samples at a sampling rate. The discrete time analog filter may filter the analog samples and provide filtered analog samples either at the sampling rate for a non-decimating filter or at an output rate that is lower than the sampling rate for a decimating filter. The discrete time analog filter may also filter the analog samples with either equal weights for a rectangular filter or at least two different weights for a weighted filter.12-31-2009
20130076434Differential Source Follower having 6dB Gain with Applications to WiGig Baseband Filters - A Sallen-Key filter requires an operational amplifier with a large input impedance and a small output impedance to meet the external filter characteristics. The operational amplifier requires an internal feedback path for stability that limits performance. This invention eliminates the need for internal feedback and increases the gain of a source follower which has characteristics matching the operational amplifier in the Sallen-Key filter. The source follower provides 6 dB of AC voltage gain and is substituted for the operational amplifier in the Sallen-Key filter. The Sallen-Key filter requires a differential configuration to generate all the required signals with their compliments and uses these signals in a feed forward path. Furthermore, since the source follower uses only two n-channel stacked devices, the headroom voltage is maximized to several hundred millivolts for a 1.2V voltage supply in a 40 nm CMOS technology. Thus, the required 880 MHz bandwidth of the Sallen-Key filter can be easily met using the innovative source follower.03-28-2013
20080224763Transferred-Impedance Filtering in Rf Receivers - The specification and drawings present a new method and apparatus for using transferred-impedance filtering in RF (radio frequency) receivers (e.g., inside of a mobile communication device), wherein said filtering can be done with MOS-switches transferring impedance of a regular RC or RCL circuit to RF frequency filtering inside an RFIC (radio frequency integrated circuit).09-18-2008
20100289566Amplitude AC noise filter with universal IEC connection - An AC noise filter designed to filter the small amplitude AC noise of all frequencies by using inline reverse coupled parallel PN semiconductors which offer a high resistance to AC voltages of less than a diode voltage drop. Inline reverse coupled parallel PN semiconductors are used in the AC power line-side as well as in the neutral-line side. For additional AC noise filtering, capacitors are coupled across the AC or DC power source input and at the output to the AC or DC user. For the AC power, IEC connectors are used at the input and output for worldwide use.11-18-2010
20100171549Variable Gain Amplifier Circuit and Filter Circuit - This variable gain amplifier is provided with an operational amplifier. The non-inversion input terminal of the operational amplifier is connected to a reference potential. A feedback resistor is connected between the output terminal and inversion input terminal of the operational amplifier. An input resistor is inserted between the inversion input terminal of the operational amplifier and the input terminal of the variable gain amplifier circuit. An adjustment resistor is connected between the inversion input terminal of the operational amplifier and the reference potential. The resistance value of the adjustment resistor is controlled in such a way as to maintain constant against the resistance value change a combined resistance value in its parallel connection with the input resistor when changing the resistance value of the input resistor.07-08-2010
20080315943Anti-Jitter Circuits - An anti jitter circuit for reducing time jitter in an input pulse train comprises an integrator, a DC removal circuit and a comparator. The anti jitter circuit also has a feedback loop effective to suppress phase deviation of the output pulse train in response to jitter.12-25-2008
20110148512FILTER CIRCUIT - A filter circuit that removes high-frequency components from an input signal, comprises: an operational amplifier; a first resistor connected between a non-inverting input terminal of the operational amplifier and an input signal source; a first capacitor connected to the non-inverting input terminal of the operational amplifier; a second resistor connected to the non-inverting input terminal of the operational amplifier; a third resistor connected between an inverting input terminal of the operational amplifier and the input signal source; a second capacitor connected between the inverting input terminal of the operational amplifier and an output terminal of the operational amplifier; and a fourth resistor connected to the inverting input terminal of the operational amplifier.06-23-2011
20080211573Tunable balanced loss compensation in an electronic filter - The invention provides a system for providing tunable balanced loss compensation in an electronic filter. Tunable balanced loss compensation is provided by using cross-connected balanced transconductors and self-connected balanced transconductors. The cross-connected balanced transconductors and the self-connected transconductors compensate the unbalanced loss across the electronic filter. The self-connected balanced transconductors compensate the balanced loss across the electronic filter. Further, the cross-connected and the self-connected balanced transconductors are tunable by adjusting the values of their transconductances, thereby providing tunable balanced loss compensation.09-04-2008
20090261897Applying trenched transient voltage suppressor (TVS) technology for distributed low pass filters - An electronic circuit includes a filtering circuit implemented with a distributed inductor-and-capacitor (LC) network that includes metal oxide effect (MOS) trenches opened in a semiconductor substrate filled with dielectric material for functioning as capacitors for the distributed LC network. The electronic circuit further includes a transient voltage suppressing (TVS) circuit integrated with the filtering circuit that functions as a low pass filter wherein the TVS circuit includes a bipolar transistor triggered by a diode disposed in the semiconductor substrate. The distributed LC network further includes metal coils to function as inductors disposed on a top surface of the semiconductor electrically contacting the MOS trenches.10-22-2009
20090108926FILTER CIRCUIT - One aspect of the embodiments utilizes a filter circuit which can be connected to a signal source has a low-frequency cutoff of 1/(R×C). The filter includes a buffer circuit which can be connected to an output end of the signal source and has an output impedance of R, and a capacitor which is connected to an output end of the buffer circuit in a floating state and has a capacitance of C/2. The filter includes a resistor circuit which is connected to an output end of the capacitor and has a resistance value of R.04-30-2009
20090212855FEEDBACK TECHNIQUE AND FILTER AND METHOD - An example filter includes a differential amplifier and a resistor string coupled between output terminals of the differential amplifier. The resistor string may generate a common mode sense voltage and an intermediate voltage at an intermediate node. A feedback resistor is coupled between the intermediate node of the resistor string and an input terminal of the differential amplifier, and a feedback capacitor is coupled between a differential output terminal of the amplifier and the differential input terminal. Applying feedback in this manner may reduce area and power requirements of the filter to achieve selected frequency and gain performance.08-27-2009
20090039954FAN SYSTEM AND FAN WITH FILTER - A filter is electrically coupled to a fan or is built-in with a fan, the filter is also electrically coupled a first power terminal and a second power terminal. The filter includes an amplifier, a capacitor, and a divider. The amplifier includes a first terminal, a second terminal and a third terminal, wherein the third terminal is electrically coupled to a power circuit of the fan. The capacitor is electrically coupled between the third terminal of the amplifier and the second power terminal. The divider is electrically coupled between the first power terminal and the second power terminal, wherein a node of the divider is electrically coupled to the second terminal of the amplifier.02-12-2009
20100225385ACTIVE POWER FILTER METHOD AND APPARATUS - This disclosure provides active power filter methods and apparatus to control the PF, harmonics and/or ripple current associated with powering electrical devices. According to one exemplary aspect, an active power filter is configured to measure the momentary ac line output current, measure the momentary ac line input current and switch an energy buffer to provide additional current to the ac line output or draw current from the ac line input to control the PF associated with the device.09-09-2010
20100201437TUNABLE RF FILTER - A tunable RF filter, comprising: an emitter follower stage (08-12-2010
20100164611LEAKAGE INDEPENDENT VRY LOW BANDWIDTH CURRENT FILTER - A current filter circuit is provided. The current filter circuit comprises a source transistor comprising a drain, a gate, and a source. The source of the source transistor is coupled to a reference voltage terminal, the gate of the source transistor is coupled to the gate of a mirror transistor, and the drain of the source transistor is coupled to a reference current source. The mirror transistor comprises a drain, a gate, and a source. The source of the mirror transistor is coupled to the reference voltage terminal, the gate is coupled to the gate of the source transistor, and the drain is coupled to a load. The current filter circuit comprises a low pass filter for filtering noise. The current filter circuit also comprises an impedance reduction circuit coupled to the drain of the mirror transistor for reducing bandwidth of the current filter circuit.07-01-2010
20100308903Filtering Arrangement, Filtering Method and Current Sensing Arrangement - A filtering arrangement comprises a reference voltage input (12-09-2010
20100321104NETWORK FILTER AND USE OF A NETWORK FILTER - A network filter includes at least one X capacitor located between two supply lines and at least one discharge resistor that discharges the X capacitor, wherein the discharge resistor is arranged in series with at least one switching element, and at least one detector circuit that recognizes a network disconnection and closes the switching element to discharge the X capacitor via the discharge resistor when a network disconnection is recognized.12-23-2010
20080204128Circuit arrangement with interference protection - A circuit arrangement with an interference protection is disclosed, including a supply line and a ground line, a first circuit and a second circuit. Each of the first and second circuit is connected to the supply line and to the ground line. The circuit arrangement also includes a blocking device coupled to at least the supply line to suppress any interfering signals from being applied to the supply line.08-28-2008
20110050333METHOD, APPARATUS, AND SYSTEM FOR OBTAINING TUNING CAPACITANCE FOR Gm-C FILTER - The present invention discloses a method, apparatus and system for obtaining the tuning capacitance of a Gm-C filter. The method includes: integrating a simulated capacitor within a given time via a current, where the simulated capacitor simulates the capacitor of the Gm-C filter which is set to an even capacitor array; and comparing the integral voltage obtained by the integration with the reference voltage, finding a simulated capacitance that makes the integral voltage equal to the reference voltage via gradual approaching by adjusting a control code, and determining the simulated capacitance as the tuning capacitance. The present invention improves the performance of a Gm-C filter without affecting the performance of the Gm-C filter.03-03-2011
20100117723ACTIVE FILTER, DELTA-SIGMA MODULATOR, AND SYSTEM - An active filter includes a first filter and a second filter. The first filter receives an input signal, and generates a first output signal by filtering the input signal. The second filter receives the first output signal during a time period adjusted based on a variation of a time constant of the first filter, and generates a second output signal by filtering the first output signal received during the time period. Therefore, a variation of a time constant is compensated by using post integration time control.05-13-2010
20100060349METHOD OF FORMING AN INTEGRATED SEMICONDUCTOR DEVICE AND STRUCTURE THEREFOR - In one embodiment, a plurality of ESD devices are used to form an integrated semiconductor filter circuit. Additional diodes are formed in parallel with the ESD structures in order to increase the input capacitance.03-11-2010
20110148513DISCRETE-TIME FILTER APPARATUS AND DISCRETE-TIME RECEIVER SYSTEM HAVING THE SAME - The discrete-time receiver system includes: a voltage current conversion device low-noise-amplifying an input voltage signal, and converting the amplified signal into a current signal; a first filter performing IIR filtering on the current signal output from the voltage current conversion device; a discrete-time filter performing FIR filtering on a signal output from the first filter; and a second filter performing IIR filtering on a signal output from the discrete-time filter, wherein the discrete-time filter includes a plurality of current supply units generating a current having a size obtained by multiplying an input current by a determined gain, respectively, an adding unit adding currents supplied from the plurality of current supply units, and a plurality of controllers connecting the plurality of current supply units and the adding unit and controlling the flow of current supplied from the current supply units to the adding unit.06-23-2011
20120206195Automatic Gain Control Circuit and Method for Automatic Gain Control - A method of attenuating an input signal to obtain an output signal is described. The method comprises receiving the input signal, attenuating the input signal with a gain factor to obtain the output signal, applying a filter having a frequency response with a frequency-dependent filter gain to at least one of a copy of the input signal and a copy of the output signal to obtain a filtered signal, the frequency-dependent filter gain being arranged to emphasize frequencies within a number N of predetermined frequency ranges, N>1; wherein the filter comprises a sequence of N sub-filters, each one of the N sub-filters having a frequency response adapted to emphasize frequencies within a corresponding one of the N predetermined frequency ranges; determining a signal strength of the filtered signal, and determining the gain factor from at least the signal strength.08-16-2012
20110057723Active polyphase filter producing two difference outputs having phase difference of pi/2 radians - An active poly-phase filter has a converting section and a filtering section having two first input terminals, two second input terminals and four output terminals. The converting section has first, second, fourth and fifth transistors forming a translinear circuit and a third transistor forming a current mirror circuit with the second transistor. The converting section converts unbalanced high-frequency power into a difference input between a collector current of the third transistor and a collector current of the first transistor having phase difference of π radians. The filtering section receives one collector current at the first input terminals and receives another collector current at the second input terminals and outputs a first difference output between outputs of two output terminals and a second difference output between outputs of other two output terminals such that the difference outputs has a phase difference of π/2 radians.03-10-2011
20110156809LOW DISTORTION MOS ATTENUATOR - An attenuation circuit uses a voltage controlled variable resistance transistor as a signal attenuator for receivers operating in the zero Hz to about 30 MHz range. The transistor functions in the linear region to linearize the transistor resistance characteristics used for signal attenuation. In an exemplary application, the attenuation circuit is used as an RF attenuator for AM radio broadcast receivers and amplifiers with automatic gain control. Multiple attenuation circuits can be coupled in parallel, each attenuation circuit having a different sized variable resistance transistor, to form sequentially activated stages that increase the range of attenuation while minimizing distortion.06-30-2011
20120007667AUTOMATIC CUTOFF FREQUENCY ADJUSTING CIRCUIT AND PORTABLE DIGITAL ASSISTANT - The disclosed invention enables the cutoff frequency of a filter to be automatically adjusted to an arbitrary setting value within the adjustment range. An automatic cutoff frequency adjusting circuit includes a voltage/current converter circuit, a charge circuit, a discharge circuit, a digital capacitance having a plurality of electrostatic capacitances, a comparator for comparing a voltage inputted to the digital capacitance with a reference voltage, and a capacitance control circuit for controlling the digital capacitance. The time until the comparator detects that the voltage inputted to the digital capacitance is higher than the reference voltage after a reset signal has become a predetermined logic level is measured, and the digital capacitance is controlled by repeating, under a predetermined condition, processing for obtaining a next setting value of the digital capacitance, based on a measurement result, a target value of the digital capacitance, and the current value of the digital capacitance.01-12-2012
20120007666DEVICE FOR IMPEDANCE MATCHING A COMPONENT, COMPRISING A FILTER HAVING MATCHABLE IMPEDANCE, BASED ON A PEROVSKITE TYPE MATERIAL - A device comprises at the input a first component (PA) having a first output impedance (Z01-12-2012
20120007668FILTER CIRCUIT, TRANSMISSION FILTER CIRCUIT, SEMICONDUCTOR INTEGRATED CIRCUIT, COMMUNICATION APPARATUS, AND TIMING ADJUSTMENT METHOD FOR FILTER CIRCUIT - A filter circuit includes two parallel digital filters, a DAC, and an LPF. The DAC includes two parallel decoders, a parallel-to-serial converter, a switch driver, and a switch. A PLL circuit supplies a reference clock to the DAC. A frequency divider provided in the DAC divides the frequency of the reference clock by two, and supplies the half frequency clock to a parallel processing section (the two decoders and the parallel-to-serial converter) of the DAC and the two digital filters. This makes it easy to secure a timing margin, permitting use in high-speed communication on the order of several GHz.01-12-2012
20120019313MILLIMETER-WAVE ON-CHIP SWITCH EMPLOYING FREQUENCY-DEPENDENT INDUCTANCE FOR CANCELLATION OF OFF-STATE CAPACITANCE - A semiconductor switching device includes a field effect transistor and an inductor structure that provides a frequency dependent inductance in a parallel connection. During the off-state of the semiconductor switching device, the frequency dependent impedance component due to the off-state parasitic capacitance of the switching device is cancelled by the frequency dependent inductance component of the inductor structure, which provides a non-linear impedance as a function of frequency. The inductor structure provides less inductance at a higher operating frequency than at a lower operating frequency to provide more effective cancellation of two impedance components of the parasitic capacitance and the inductance. Thus, the semiconductor switching device can provide low parasitic coupling at multiple operating frequencies. The operating frequencies of the semiconductor switching device can be at gigahertz ranges for millimeter wave applications.01-26-2012
20120019314CURRENT-MODE ANALOG BASEBAND APPARATUS - A current-mode analog baseband apparatus is provided. The apparatus includes a current-mode low-order filter, a current-mode programmable gain amplifier (PGA) unit and a high-order filter. The input impedance is smaller than the output impedance in the current-mode low-order filter. An input terminal of the current-mode PGA unit is connected to an output terminal of the current-mode low-order filter. An input terminal of the high-order filter is connected to an output terminal of the current-mode PGA unit.01-26-2012
20120112825MODULES FOR AN ACTIVE MAINS FILTER AND ACTIVE MAINS FILTER - A module for an active mains filters for determining reference currents for a subsequent current adjustment control with transformation of the inflowing currents, first determines active power of the load, then directly calculates the reference currents taking into account the active power and the α-β components of the mains voltage. A module for an active mains filter for compensating one or more harmonic currents or voltages using selective signal analysis and an active mains filter for a 3-phase supply mains with a reference module for determining reference currents are also provided.05-10-2012
20120025903Sampling of Multiple Data Channels Using a Successive Approximation Register Converter - Provided is a method for performing analog to digital conversion of a plurality of analog signal channels. The method may comprise successively processing each analog signal channel of a plurality of analog signal channels. The processing of an analog signal channel of the plurality of analog signal channels may comprise: selecting the analog signal channel from the plurality of analog signal channels, generating an analog output signal corresponding to an analog input signal transmitted over the selected analog signal channel, and sampling the analog output signal using a successive approximation register (SAR) converter. Sampling the analog output signal using a SAR converter may comprise sampling the analog output signal a specific number of times to produce a respective plurality of digital samples corresponding to the selected analog input signal.02-02-2012
20120212287ADAPTIVE FILTER CIRCUIT FOR SAMPLING A REFLECTED VOLTAGE OF TRANSFORMER IN A POWER CONVERTER AND METHOD THEREOF - An adaptive filter circuit for sampling a reflected voltage of a transformer of a power converter includes a first switch for receiving the reflected voltage, a resistor having a first terminal and a second terminal, the first terminal of the resistor being coupled to the first switch, a capacitor coupled to the second terminal of the resistor for holding the reflected voltage, and a second switch coupled to the resistor in parallel, wherein the resistor and the capacitor develop a filter for sampling the reflected voltage which is sampled without filtering by the filter in a first period during a disable period of a switching signal and also sampled with filtering by the filter in a second period during the disable period of the switching signal.08-23-2012
20120169414METAMATERIAL POWER AMPLIFIER SYSTEMS - Power amplifying systems and modules and components therein are designed based on CRLH structures, providing high efficiency and linearity.07-05-2012
20120188006Self-Calibrated, Broadband, Tunable, Active Filter with Unity Gain Cells for Multi-Standard and/or Multiband Channel Selection - An exemplary filter includes N (≧2) unity gain amplifiers, each with a pair of differential input terminals and a pair of differential output terminals; a pair of filter differential input terminals; a first pair of variable resistances coupling the pair of filter differential input terminals to the pair of differential input terminals of the first unity gain amplifier; N−1 pairs of variable resistances coupling the pairs of differential output terminals of each of the N unity gain amplifiers, other than the last one, to the pairs of differential input terminals of its downstream neighbor; N−1 pairs of variable capacitances coupling the pairs of differential input terminals of each of the N unity gain amplifiers, other than the last one, to the pairs of differential output terminals of its downstream neighbor; and a variable capacitance coupling the pair of differential input terminals of the last unity gain amplifier to each other.07-26-2012
20120262228CURRENT-MODE ANALOG BASEBAND APPARATUS - A current-mode analog baseband apparatus is provided. The apparatus includes a current-mode low-order filter, a current-mode programmable gain amplifier (PGA) unit and a high-order filter. The input impedance is smaller than the output impedance in the current-mode low-order filter. An input terminal of the current-mode PGA unit is connected to an output terminal of the current-mode low-order filter. An input terminal of the high-order filter is connected to an output terminal of the current-mode PGA unit.10-18-2012
20100327965RECEIVER FILTERING DEVICES, SYSTEMS, AND METHODS - Exemplary embodiments of the invention disclose receiver baseband filtering. In an exemplary embodiment, the filter device may comprise a continuous-time filter and a discrete-time filter operably coupled to the continuous time-filter. The discrete-time filter may include a passive infinite impulse response filter operably coupled between the continuous-time filter and an amplifier. The discrete-time filter may also include an active infinite impulse response filter operably coupled between an output of the amplifier and an input of the amplifier. The discrete-time filter may be configured to combine an output of the active infinite impulse response filter and an output of the passive infinite impulse response filter to form a composite signal. Furthermore, the amplifier may be configured to receive and amplify the composite signal.12-30-2010
20120319767Single-Ended-To-Differential Filter Using Common Mode Feedback - A filter including common mode feedback can provide single-ended to differential-ended conversion with minimum loss of performance.12-20-2012
20120092065FILTER CIRCUIT AND COMMUNICATION SEMICONDUCTOR DEVICE USING THE SAME - The present invention intends to provide a filter circuit in which an area occupied by the circuit can be reduced by suppressing the scale of its circuit configuration while a predetermined vicinity disturbance wave rejection ratio is maintained and a communication semiconductor device using the same, the filter circuit filtering an analog signal and including a voltage/current conversion circuit for converting the analog signal from voltage to current, and a capacitor array which executes signal processing by charging/discharging the current converted by the voltage/current conversion circuit to/from plural capacitors, the capacitor array being so constructed that the plural capacitors are divided to plural stages so that signals averaged by the capacitor on a preceding stage are accumulated in the capacitor on a next stage successively.04-19-2012
20120326773SYSTEMS AND METHODS FOR POWER TRANSFER BASED ON RESONANCE COUPLING OF INDUCTORS - An integrated circuit (IC) includes first and second resonator circuits and an isolation barrier. The first resonator circuit includes first and second inductors, wherein the first resonator circuit is connected to a supply voltage. The second resonator circuit includes third and fourth inductors, wherein the second resonator circuit is matched to the first resonator circuit. The isolation barrier separates the first and second resonator circuits. The first and second inductors are inductively coupled to the third and fourth inductors, respectively, thereby providing for transfer of power from the first resonator circuit across the isolation barrier to the second resonator circuit.12-27-2012
20100171548ANALOG FIR FILTER - An analog finite impulse response (AFIR) filter including at least one variable transconductance block having an input for receiving an input voltage and being adapted to sequentially apply each of a plurality of transconductance levels to the input voltage during at least one of a plurality of successive time periods to generate an output current at an output of the variable transconductance block, the at least one variable transconductance block including a plurality of fixed transconductance blocks each receiving the input voltage and capable of being independently activated to supply the output current; and a capacitor coupled to the output of the variable transconductance block to receive the output current and provide an output voltage of the filter.07-08-2010

Patent applications in class Active filter

Patent applications in all subclasses Active filter