| Class / Patent application number | Description | Number of patent applications / Date published |
|---|
| 327554000 | Switched capacitor filter | 31 |
| 20080284505 | Filter Circuit for Wireless Applications and Noise Reduction Method - An object of the present invention is to provide a filter circuit which improves NF of a Gm-C filter. The filter circuit comprises a filter comprising at least one first operational transconductance amplifier whose mutual conductance varies depending on a first control signal and a first capacitor, a second operational transconductance amplifier whose mutual conductance is controlled by the first control signal, a third operational transconductance amplifier whose mutual conductance is controlled by a second control signal, and a second capacitor connected to output terminals of the first and second operational transconductance amplifiers and input terminals of the filter. | 11-20-2008 |
| 20090002066 | Multi-Tap Direct Sub-sampling Mixing System for Wireless Receivers - A multi-tap direct sub-sampling mixing system for wireless receivers is provided with a dynamically configurable passive switched capacitor filter. A front end amplifier is connected to receive a signal. The passive switched capacitor filter is connected to receive the amplified signal and has an output for providing a filtered signal. The switched capacitor filter has at least two sections that are each operable as a pole, wherein a first section of the at least two sections has sets of at least two stacked capacitors interconnected with a set of switches operable to amplify in input voltage provided to an input of the first section in response to operation of the set of switches; and a back end section connected to the output of the switched capacitor filter to receive the filtered signal. | 01-01-2009 |
| 20090021297 | SIGNAL PROCESSING APPARATUS, FILTER APPARATUS, SIGNAL PROCESSING METHOD AND FILTERING METHOD - There is provided a signal processing apparatus including a variable capacitor and a switching portion for switching the circuit mode between a sampling mode, in which the variable capacitor samples an input signal, a holding mode, in which a charge gained by sampling the input signal is held in the variable capacitor, and an output mode for outputting the charge stored in the variable capacitor, wherein the variable capacitor is provided with an input terminal through which the input signal is inputted in the sampling mode, a control terminal to which a first control signal which decreases the capacitance of the variable capacitor to a value below the capacitance in the sampling mode is inputted in the output mode, and a second control signal having a predetermined reference voltage is inputted in the holding mode, where an insulating layer is provided between the control terminal and the input terminal. | 01-22-2009 |
| 20090051421 | SWITCHED CAPACITOR INTEGRATION AND SUMMING CIRCUITS - A switched capacitor circuit employs a single operational amplifier to implement both an integrator and a summer. One input signal is routed to the input of the operational amplifier through (1) one or more integration branches, and (2) one or more first summing branches. A second input signal is routed to the input of the operational amplifier through one or more second summing branches. Each of the branches includes a capacitor and a number of switches controlled by different clock phases. The switched capacitor circuit may be single-ended or differential. The circuit may be used in an access terminal of a cellular communication system. The access terminal may operate under a code division multiple access (CDMA) communication standard. | 02-26-2009 |
| 20090051422 | Filter Device - Provided is a switched capacitor type filter device having a steep characteristic with a small number of taps. The filter device includes positive polarity selecting switches ( | 02-26-2009 |
| 20090091378 | Statistical Switched Capacitor Droop Sensor for Application in Power Distribution Noise Mitigation - A circuit and a method for detecting noise events in a system with time variable operating points is provided. A switched capacitor filter comprising a plurality of capacitor units, samples a first voltage to determine an average of a set of voltage measurements, forming an average voltage. A filter control unit controls the plurality of capacitor units in the switched capacitor filter. A comparing unit compares the average voltage to the first voltage to form a comparison. A signaling unit generates a signal to instruct circuits in a processor to initiate actions to keep the first voltage from drooping below a threshold level in response to the comparison. | 04-09-2009 |
| 20090096516 | Semiconductor integrated circuit device having control circuit to selectively activate decoupling cells - The semiconductor integrated circuit device includes a plurality of decoupling cells that suppress power noise respectively, a plurality of power switches that connect the decoupling cells to a power line respectively, and a control circuit that controls the number of power switches selected from among the plurality of power switches and to be turned on according to power noise to be changed according to the operation state of each of internal circuits driven by a power supplied from the power line. | 04-16-2009 |
| 20090134938 | Charge Domain Filter Circuit - A charge domain filter circuit includes a first signal output portion, at least one second signal output, portion, a third signal output portion, and an adder portion. The first signal output portion outputs a first signal that is sampled at a specified time interval. Each second signal, output portion outputs a second signal that is sampled after a specified delay after the first signal is sampled. Where a plurality of the second signal output portions is included, the second signals are sampled in succession. The third signal output portion outputs a third signal that is sampled after a specified delay after the last second signal is sampled. The adder portion adds the first, second, and third signals together and outputs the result. The capacitance ratio of the sampling capacitors in the first signal output portion and the second signal output portion is one of continuously or discretely varied. | 05-28-2009 |
| 20090146735 | SWITCHED CAPACITOR RESONATOR AND SIGMA-DELTA MODULATOR USING THE SAME - Provided is a switched capacitor resonator including at least one integrator circuit having a differential operational amplifier and a sub feedback circuit configured with a switched capacitor circuit. A main feedback circuit connecting main input and output terminals of the switched capacitor resonator to each other may be configured with the switched capacitor circuit. The main feedback circuit may be connected to the sub feedback circuit included in one of the integrator circuits. A capacitor of the main feedback circuit can serve as an integration capacitor connected between the input and output terminals of the differential operational amplifier. Consequently, it is possible to improve an operating speed by reducing a settling time constant of the integrator circuit. | 06-11-2009 |
| 20090302934 | LOW-CONSUMPTION SWITCHED-CAPACITOR CIRCUIT - A switched-capacitor circuit including at least one first capacitor and a circuit for switching at least one armature of the first capacitor alternately to one and the other of two terminals at a switching frequency. The circuit further includes a second capacitor connected to the first capacitor at a node; and a filtering circuit connecting the node to a virtual ground only for frequencies belonging to a frequency range. | 12-10-2009 |
| 20100073081 | INTEGRATED TRACKING FILTER - An integrated tracking filter includes: an amplifying unit having first to third terminals, the first terminal being connected to an input stage and the second terminal being connected to an output stage, and amplifying a signal from the input stage; a loading unit connected between a power source stage and the second terminal of the amplifying unit; a current source connected between the third terminal of the amplifying unit and a ground; and a switched LC filter unit connected between the third terminal of the amplifying unit and the ground and varying a pass band of the signal. | 03-25-2010 |
| 20100090757 | Circuit and method for improved frequency resolution of wide-bandwidth digitally programmable RC active filters - An active RC filter ( | 04-15-2010 |
| 20100090758 | LOW-PASS FILTER - A low-pass filter of the present invention comprises a plurality of filter units and a regulation unit. The filter units are coupled in series with each other and receive an input signal to filter the input signal for generating an output signal. The regulation unit is coupled to the filter units to regulate voltage levels of the filter units. The low-pass filter of the present invention can be integrated within the integrated circuit and reduce the prime cost. | 04-15-2010 |
| 20100201438 | NOTCH FILTER AND APPARATUS FOR RECEIVING AND TRANSMITTING RADIO-FREQUENCY SIGNALS INCORPORATING SAME - A notch filter suitable for attenuating certain frequencies of a radio-frequency signal includes an input for receiving the radio-frequency signal and an output for the output of a portion of the radio-frequency signal, first and second capacitive means, at least one inductor and a negative resistance circuit suitable for compensating the resistive losses of said at least one inductor. The inductor and the first and second capacitive means are placed to produce a resonator and the filter comprises a control device suitable for controlling the negative resistance circuit. The input impedance of the filter comprises a pole and a zero, with the pole depending on the second capacitive means and the zero depending on both the first and second capacitive means. The first and second capacitive means are variable and the control device is suitable for controlling the first and second capacitive means. | 08-12-2010 |
| 20100289567 | FILTER CIRCUIT AND COMMUNICATION DEVICE - A filter circuit includes a voltage-current conversion portion that converts a voltage signal input to an input terminal to a current signal, a first capacitor unit formed by a plurality of capacitors, and in which a current signal output from the voltage-current conversion portion is sequentially input to the capacitors, the unit adding and outputting electric charges of a group of capacitors to which the current signal is input, a second capacitor unit formed by a plurality of capacitors, and in which a current signal output from the first capacitor unit is sequentially input to the capacitors, the unit adding and outputting electric charges of a group of capacitors to which the current signal is input, and a plurality of connection nodes that respectively connect a given capacitor in the first capacitor unit and a capacitor in the second capacitor unit. | 11-18-2010 |
| 20100321105 | SWITCHED CAPACITOR NOTCH FILTER - A switched capacitor notch filter for sampling an input signal using multiple sampling capacitors and multiple non-overlapping time periods. The charge from the sampling capacitors is averaged and transferred to the filter output during another non-overlapping time period. | 12-23-2010 |
| 20110121893 | CHARGE DOMAIN FILTER - A charge domain filter having a phase divider, first switched capacitor networks, second switched capacitor networks and a connecting circuit. The phase divider receives a first and a second input signal to output first phase divided signals based on the first input signal and second phase divided signals based on the second input signal. The first switched capacitor networks, holding a one to one relationship with the first phase divided signals, each has an input terminal receiving the corresponding first phase divided signal and has an output terminal. The second switched capacitor networks, holding a one to one relationship with the second phase divided signals, each has an input terminal receiving the corresponding second phase divided signal and has an output terminal. The connecting circuit determines connections between the output terminals of the first and second switched capacitor networks to generate a plurality of output signals. | 05-26-2011 |
| 20110128071 | FILTER AUTOMATIC ADJUSTMENT CIRCUIT AND METHOD FOR ADJUSTING CHARACTERISTIC FREQUENCY OF FILTER, AND WIRELESS COMMUNICATION APPARATUS PROVIDED WITH THE SAME - A filter automatic adjustment circuit is provided for adjusting a characteristic frequency of a main filter whose characteristic frequency is adjustable with a reference signal frequency served as a target frequency. A reference filter has modes selectively changed over, and filters an inputted reference signal. A phase difference detector detects a phase difference between an input signal inputted to the reference filter and an output signal from the reference filter, and outputs a signal having a duty ratio corresponding to a phase difference caused by the reference filter. A counter counts a duty ratio corresponding to the phase difference caused by the reference filter based on the output signal from the phase difference detector and the reference signal, and outputs a signal representing a counted duty ratio. A decoder decodes the output signal from the counter into a control signal for variation correction on the main filter. | 06-02-2011 |
| 20110221518 | SWITCHED CAPACITOR NOTCH FILTER WITH FAST RESPONSE TIME - A switched capacitor notch filter for sampling an input signal using multiple sampling capacitors during multiple non-overlapping time periods. The charge from one set of sampling capacitors is averaged and transferred to the filter output during one non-overlapping time and the charge from another set of sampling capacitors is averaged and transferred to the filter output during a second non-overlapping time period. | 09-15-2011 |
| 20110291750 | CHARGE DOMAIN FILTER AND BANDWIDTH COMPENSATION CIRCUIT THEREOF - A charge domain filter (CDF) and a bandwidth compensation circuit of the CDF are provided. The CDF includes an amplifier, a plurality of switch-capacitor networks (SCNs), a connector, a current adder (CA) and a bandwidth compensation circuit. A first input terminal of the amplifier receives an input signal, and an output terminal thereof is connected to input terminals of the SCNs. The connector is connected between the output terminal of the SCNs and the CA for configuring coupling status of the output terminals of the SCNs and input terminals of the CA. The bandwidth compensation circuit senses a portion of or all of the output terminals of the SCNs and the CA, and outputs the sensing result to a second input terminal of the amplifier. | 12-01-2011 |
| 20120025904 | AREA-OPTIMIZED ANALOG FILTER WITH BANDWIDTH CONTROL BY A QUANTIZED SCALING FUNCTION - A programmable active frequency-selective circuit includes a first capacitor having a fixed value and a second capacitor having a value defined by a product of a parameter and a plurality of switchable capacitors, wherein the parameter is defined by a gain, a bandwidth mode, and a process resolution. The parameter may be stored in a form of a look-up table and enables a user or manufacturer to program the gain, select the bandwidth mode and tune the process. The frequency-selective circuit may include a differential input and a differential output having a first feedback path connected across a positive output terminal to a negative input terminal and a second feedback path connected across a negative output terminal and a positive input terminal. | 02-02-2012 |
| 20120194265 | SEMICONDUCTOR INTEGRATED CIRCUIT AND OPERATION METHOD OF THE SAME - The present invention is directed to accurately set a frequency characteristic of a filter integrated in a semiconductor integrated circuit. A semiconductor integrated circuit includes a filter circuit, a cutoff frequency calibration circuit, and a Q-factor calibration circuit. The cutoff frequency calibration circuit adjusts cutoff frequency of the filter circuit to a desired value by adjusting capacitance components of the filter circuit. After adjustment of the cutoff frequency of the filter circuit by the cutoff frequency calibration circuit, the Q-factor calibration circuit adjusts the Q factor of the filter circuit to a desired value by adjusting a resistance component of the filter circuit. | 08-02-2012 |
| 20120280745 | MULTI-LAYER SWITCHING IN CHARGE-DOMAIN OR SAMPLING IF FILTERS - A signal filter system which uses two groups of switches to couple tap current cells with integrating cells. The first group of switches couples tap current cells with at least one shared connection or bus while the other group of switches couples the shared connection or bus with the integrating cells. Multiple shared connections can be used and the tap current cells can be divided into groups with each group sharing at least one shared connection that is dedicated to that group. The system also allows for more than one tap current cell to simultaneously be coupled to a single integrating cell. | 11-08-2012 |
| 20120286857 | SWITCHED CAPACITOR CIRCUIT WITH SWITCHING LOSS COMPENSATION MECHANISM AND COMPENSATION METHOD THEREOF - A switched capacitor circuit with switching loss compensation mechanism includes a resonant unit and a loss compensation unit. The resonant unit generates a resonant frequency and includes a capacitor switching unit for switching an output capacitor. The loss compensation unit is coupled to the resonant unit for providing loss compensation when the capacitor switching unit outputs different capacitance values. | 11-15-2012 |
| 20130049850 | CHARGE DOMAIN FILTER APPARATUS - A charge domain filter (CDF) apparatus having a bandwidth compensation circuit is provided. The bandwidth compensation circuit includes a configurable power-reference cell (CPC) and/or a programmable-delay cell (PDC). The CPC receives and adjusts an output of the CDF to obtain a sensing power, and outputs the sensing power to the CDF. The PDC receives and delay an output of the CDF, and outputs a delay result to the CDF. The bandwidth compensation circuit having a flexible structure, so as to implement X-axis (frequency) compensation and/or Y-axis (power or gain) compensation of a frequency response diagram according to a design requirement. | 02-28-2013 |
| 20130113550 | SWITCHED-CAPACITOR FILTER - A filter is implemented as cascaded stages, and in at least one stage all resistances are implemented as double-sampled switched-capacitor circuits. In a variation, at least one resistance is implemented as a double-sampled switched-capacitor T-network. In a variation, in an integrator stage, a resistance is implemented as a transconductance, and the cutoff frequency of the integrator stage scales with a switching frequency of a DC-DC voltage converter. | 05-09-2013 |
| 20130271210 | N-PATH FILTER WITH COUPLING BETWEEN PATHS - An N-path filter with each path forming a different filter. A signal insertion block is provided at the start of the circuit and, in one embodiment, multiple memory capacitors are coupled to the signal insertion block. A bank of sequential rotating capacitors are provided along with a bank of switches. By activating selected switches, any of the memory capacitors can be coupled to selected rotating capacitors. A different filter subcircuit is formed by coupling each memory capacitor to different rotating capacitors as this creates a different signal path. By timing the switching of the rotating capacitors, signals from previous outputs can be inserted into the circuit. At the output end of the circuit, the output of the different filter subcircuits is put together into an output for the whole circuit. | 10-17-2013 |
| 20140176233 | Bandwidth Calibration for Filters - A low power, high accuracy calibration circuit for filter calibration is provided. The calibration circuit includes a chargeable voltage storage element. A first measurement and adjustment circuit determines a charge time required for the voltage of the chargeable voltage storage element to substantially match a reference voltage. The circuit adjusts the voltage storage element to make the charge time approximately equal to a predetermined filter time constant value, the adjustment circuit updating the reference voltage to make the charge time substantially equal to the predetermined filter time constant value and iteratively updating the reference voltage to refine the charge time. A second circuit is configured to have substantially the predetermined filter time constant value based on the adjustment configuration determined by the adjustment of the voltage storage element and the reference voltage of the first circuit. | 06-26-2014 |
| 20150048881 | NOISE REMOVING CIRCUIT AND CURRENT SENSING UNIT INCLUDING THE SAME - A noise-removing circuit includes a first capacitor to charge a first voltage supplied to a first node during a first period in which a first switching control signal is supplied, a second capacitor to charge a second voltage supplied to a third node during the first period, a third capacitor to charge the first voltage during a second period in which a second switching control signal is supplied, and to charge the second voltage charged in the second capacitor as a third voltage during a third period in which a third switching control signal is supplied, a fourth capacitor to charge the second voltage during the second period, and to charge the first voltage charged in the first capacitor as a fourth voltage during the third period, and a differential amplifier to output a voltage difference between the third voltage and the fourth voltage. | 02-19-2015 |
| 20150318841 | METHOD OF IMPROVING NOISE IMMUNITY IN A SIGNAL PROCESSING APPARATUS, AND A SIGNAL PROCESSING APPARATUS HAVING IMPROVED NOISE IMMUNITY - A signal processing apparatus that includes a circuit in which a signal processing function is performed during a first time period, the signal processing apparatus including or being associated with a switch or a filter in a power supply to the signal processing apparatus so as to disconnect the signal processing apparatus from the power supply or to filter the power supply during a second time period that is coincident with at least part of the first time period. | 11-05-2015 |
| 20160065179 | HIGH ACCURACY MILLIMETER WAVE/RADIO FREQUENCY WIDEBAND IN-PHASE AND QUADRATURE GENERATION - Certain aspects of the present disclosure provide circuits for generating high accuracy millimeter wave or radio frequency (RF) wideband in-phase (I) and quadrature (Q) oscillating signals having acceptable amplitude and phase mismatch over process, voltage, and temperature (PVT) variations with reduced cost, area, and power consumption. In one example apparatus, a polyphase filter having a first stage and a second stage is provided. Each stage comprises resistive elements and capacitive elements. Certain aspects of the present disclosure provide for intentional resistive and/or capacitive value mismatch between the resistive or capacitive values of one or multiple stages such that the phase mismatch between the resulting I and Q signals may be reduced without degrading the amplitude mismatch. Certain aspects of the present disclosure provide for replacing the resistive elements in at least one stage with transistors operating in the triode region, where the on-resistance is controlled by a feedback network. | 03-03-2016 |
