Multiple Feedback Paths Patents (Class 330/103)
  • Patent number: 10263574
    Abstract: A radio frequency receiver device comprises: a receiver input arranged to receive signals having one or more frequency components within a frequency spectrum; a filter having a filter output impedance; and an amplifier comprising: an amplifier input (134a, 134b) connected to the filter output; an amplifier output 72a, 72b); at least one radio frequency input transistor (144a, 144b); and a feedback circuit including at least one feedback resistor (146a, 146b). The device is arranged to be selectably operable in: a first mode wherein the amplifier has first feedback resistance and transconductance values respectively such that the amplifier input impedance and the filter output impedance are substantially the same; and a second mode having second feedback resistance and transconductance values such that upon connection of a predetermined external impedance matching circuit (160) between the filter and the amplifier, the amplifier input impedance and the filter output impedance are substantially the same.
    Type: Grant
    Filed: October 31, 2016
    Date of Patent: April 16, 2019
    Assignee: Nordic Semiconductor ASA
    Inventor: Pete Sivonen
  • Patent number: 10068120
    Abstract: Improving fingerprint image measurement despite damage to the stratum corneum. Determining whether a fingerprint image is adequate for matching with a database. If not, re-measure those image portions that are inadequate (overexposed or underexposed), such re-measuring a minimal selection of image portions. An amount of time or power to re-measure is minimized. Improving fingerprint image data collection despite fixed pattern noise like saturated bars in blocks of picture elements. Determining a histogram of grayscale values, removing fixed pattern noise, and expanding real histogram values to obtain more bits of precision.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: September 4, 2018
    Assignee: Apple Inc.
    Inventors: Benjamin B. Lyon, Giovanni Gozzini
  • Patent number: 9662025
    Abstract: Circuits and circuit systems to record activity (e.g., peripheral nerve activity) are provided. The circuits advantageously have good noise characteristics (e.g., low noise), as well as low power consumption and low area. A circuit can be implantable (e.g., in a human subject). Methods of designing, manufacturing, and using such circuits and circuit systems are also provided.
    Type: Grant
    Filed: May 3, 2013
    Date of Patent: May 30, 2017
    Assignee: The Florida International University Board of Trustees
    Inventors: Adeline Zbrzeski, Ranu Jung
  • Patent number: 9525388
    Abstract: A new compensation system for an audio input reduces noise by matching feedback ratios in the positive and negative paths. A variable resistance network allows for fine control of resistance trimming in one of the signal paths, which allows for compensation between tolerance of resistors that are external to an integrated circuit and those that are internal to the integrated circuit.
    Type: Grant
    Filed: July 3, 2014
    Date of Patent: December 20, 2016
    Assignee: AVNERA CORPORATION
    Inventors: Ali Hadiashar, Wai Lang Lee
  • Patent number: 9414105
    Abstract: A system for transmission and rendering of media data over an Internet Protocol network from portable data storage source devices to spatially-separated destination devices located at lifestyle-determined locations. Destination devices are brought online by a discovery process as they come in the vicinity of a source device. In the interest of speed, discovery messages utilize low-overhead, asynchronous messaging. The discovery process begins with multicasting from a source device to local destination devices of discovery messages which include a unique session key and zone, priority and ID specifications, followed by unicasting of a discovery acknowledgement message from destination devices to the source device, and unicasting of a configuration message from the source device to destination devices. In one preferred embodiment, the latest source device to come into the vicinity of a destination device becomes the source of the media rendered by the destination device.
    Type: Grant
    Filed: February 14, 2012
    Date of Patent: August 9, 2016
    Assignee: Blackfire Research Corporation
    Inventor: Ravi Rajapakse
  • Patent number: 9369108
    Abstract: Device for correction of the passband of an air gap transformer with a cut-off frequency, characterized in that it includes a filter adapted to be connected to the transformer in series, and in that the filter is adapted to amplify the signal that it receives from the transformer for frequencies below the cut-off frequency of the transformer, so that the passband of the transformer fitted with the correction device is increased and has a cut-off frequency lower than the cut-off frequency of the transformer.
    Type: Grant
    Filed: July 21, 2014
    Date of Patent: June 14, 2016
    Assignee: SCHNEIDER ELECTRIC INDUSTRIES SAS
    Inventor: Michel Guenego
  • Patent number: 9274145
    Abstract: An active shunt ammeter for measuring current flowing through a device under test (DUT) and method are disclosed. The active shunt ammeter includes an input configured to receive an input signal having a frequency within a frequency band and representing the current flowing through the DUT. An output is configured to generate an output voltage representing the current flowing through the DUT. The active shunt ammeter also includes a gain circuit having an amplifier with a gain characteristic that varies respect to frequency within the frequency band and a feedback element having an impedance coupled from an output of the gain circuit to a negative input of the gain circuit, the feedback element impedance being configured to change with frequency to correlate with the amplifier gain characteristic such that the feedback element impedance divided by the amplifier gain over the frequency band has minimal frequency dependency.
    Type: Grant
    Filed: October 22, 2012
    Date of Patent: March 1, 2016
    Assignee: TEKTRONIX, INC.
    Inventor: Wayne C. Goeke
  • Publication number: 20150102858
    Abstract: An amplifier includes an amplifier input and an amplifier output. A compensation network is coupled to the amplifier output. The compensation network includes at least one RC network tuned to a frequency in which the amplifier operates. The compensation network provides at least one zero to compensate for at least one pole introduced by a load coupled to the amplifier output.
    Type: Application
    Filed: October 7, 2014
    Publication date: April 16, 2015
    Inventors: Srinivas K. Pulijala, Steven G. Brantley
  • Patent number: 8952753
    Abstract: A highly efficient, high control bandwidth and high-speed power supply with a linear driver and a switching regulator for regulating an output based on a control signal. The linear driver has a first input for receiving the control signal and a second input connected to the output for receiving negative feedback. The driver's output is controlled by its two inputs and has a capacitor connected in series with it to generate a capacitor voltage VC responsive to the DC and low frequency components in the driver's output. The switching regulator has a control input and a regulator output connected in a regulator feedback loop. The control input receives capacitor voltage VC and the regulator feedback loop minimizes capacitor voltage VC. Thus, switching regulator takes over the generation of DC and low frequency components, while the linear driver provides high frequency output current components.
    Type: Grant
    Filed: February 17, 2012
    Date of Patent: February 10, 2015
    Assignee: Quantance, Inc.
    Inventors: David C. G. Tournatory, Martin A. Tomasz
  • Publication number: 20140306754
    Abstract: A RF power supply system for delivering periodic RF power to a load. A power amplifier outputs a RF signal to the load. A sensor measures the RF signal provided to the load and outputs signals that vary in accordance with the RF signal. A first feedback loop enables control the RF signal based upon power determined in accordance with output from the sensor. A second feedback loop enables control the RF signal based upon energy measured in accordance with signals output from the sensor. Energy amplitude and duration provide control values for varying the RF signal. The control system and techniques are applicable to both pulsed RF power supplies and in various instances to continuous wave power supplies.
    Type: Application
    Filed: July 7, 2014
    Publication date: October 16, 2014
    Inventors: David J. COUMOU, Richard PHAM
  • Patent number: 8837633
    Abstract: A communication system includes digital signals that carry data and correspond to channels of a composite signal to be transmitted across a communication channel. Active channels are detected and used to configure digital processing. In one embodiment, active channels are detected, where a particular active channel corresponds to the presence of a particular one of the digital signals. Active channel detection may be used to configure pre-distortion of a composite signal to be transmitted to compensate for distortion in a digital-to-analog converter. Likewise, active channel detection may be used to optimize the configuration of an up-converter. In one embodiment, a programmable device is configured based on detected active channels into a plurality of different configurations.
    Type: Grant
    Filed: October 21, 2011
    Date of Patent: September 16, 2014
    Assignee: Xilinx, Inc.
    Inventor: Christopher H. Dick
  • Patent number: 8773199
    Abstract: Compensation methods and systems for voltage-feedback amplifiers provide improved dynamic performance (i.e., increased bandwidth and the elimination or alleviation of a slew limitation) at various gains by self-adaptively changing the Miller effect with respect to the gain setting.
    Type: Grant
    Filed: September 26, 2012
    Date of Patent: July 8, 2014
    Assignee: Analog Devices, Inc.
    Inventor: Quan Wan
  • Publication number: 20140009225
    Abstract: A method and system for determining adaptation parameters for pre-distorters in a multi-band power amplifier system of a communication system are disclosed. A method includes receiving, at an adaptor, a reference signal comprising a first plurality of signals having substantially overlapping frequency spectra. Each of the first plurality of signals is input to a corresponding one of a plurality of pre-distorters. The adaptor also receives an observation signal comprising a second plurality of signals tuned to substantially a same frequency to have overlapping frequency spectra. Each of the second plurality of signals is derived from an output of the multi-band power amplifier system. The adaptor computes the adaptation parameters based on the reference signal and the observation signal.
    Type: Application
    Filed: July 5, 2012
    Publication date: January 9, 2014
    Applicant: TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
    Inventor: Pierre-André LAPORTE
  • Patent number: 8532752
    Abstract: A biosignal amplifying device includes: an operational amplifier (op-amp); a capacitor load including a first capacitor connected with a first input terminal of the op-amp, and in which a first voltage is inputted from a first electrode, and a second capacitor which is connected with a second input terminal of the op-amp, and in which a second voltage is inputted from a second electrode; a feedback capacitor load including a first feedback capacitor connected with the first input terminal and an output terminal, and a second feedback capacitor connected with the second input terminal; and a feedback resistor load including a first feedback resistor connected with the first input terminal and the output terminal, and a second feedback resistor connected with the second input terminal.
    Type: Grant
    Filed: December 21, 2007
    Date of Patent: September 10, 2013
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Jong Pal Kim, Kun Soo Shin
  • Patent number: 8466742
    Abstract: The present invention relates to a large time constant steering circuit for slowly changing a voltage on a node between at least two discrete voltage levels. The present invention further relates to a slow steering current DAC comprising said large time constant steering circuit. The present invention further relates to an instrumentation amplifier device comprising a current balancing instrumentation amplifier for amplifying an input signal to an amplified output signal and a DC servo-loop for removing a DC-component from the input signal. The present invention further relates to an EEG acquisition ASIC comprising said instrumentation amplifier device.
    Type: Grant
    Filed: February 25, 2011
    Date of Patent: June 18, 2013
    Assignees: IMEC, Katholieke Universiteit Leuven, K.U. Leuven R&D
    Inventors: Refet Firat Yazicioglu, Patrick Merken
  • Patent number: 8335478
    Abstract: Provided are a first filter 63a and a second filter 63b each having a pass band in the range of a frequency band that is obtained by, for example, substantially bisecting a frequency band of f1 to f4. In that case, the regions of the first filter 63a and the second filter 63b partially overlap with each other with the center frequency f5 interposed therebetween. In practice, even if the division is not bisection, a configuration is adopted in which a frequency region of the wider band (the first frequency band 61a) closer to a second frequency band 61b side is covered by the second filter 63b. Accordingly, it is possible to suppress the influence of load fluctuation in a multiband-compatible radio communication device.
    Type: Grant
    Filed: July 30, 2008
    Date of Patent: December 18, 2012
    Assignee: Sharp Kabushiki Kaisha
    Inventor: Hiroki Kashiwagi
  • Publication number: 20120223772
    Abstract: A multilevel class-D differential amplifier which can be operated in at least three modes includes a first power stage and a second power stage. In an idle mode, an output of the first power stage varies between a first voltage level and a second voltage level, wherein an output of the second power stage varies between the first voltage level and the second voltage level. In a PWM mode, the output of the first power stage varies between the first voltage level and the second voltage level, wherein the output of the second power stage varies between the first voltage level and the second voltage level. In a Multi-Level mode, the output of said first power stage varies between said second voltage level and a third voltage level, wherein said output of said second power stage is fixed at said first voltage level, and wherein said differential signal between said outputs of said power stages is pulse width modulated.
    Type: Application
    Filed: March 1, 2011
    Publication date: September 6, 2012
    Inventor: Cristian Cerutti
  • Patent number: 8232841
    Abstract: An amplifier circuit includes an amplifier including an inverting input that communicates with an input signal, a non-inverting input, and an output. A first feedback path communicates with the inverting input and the output of the amplifier. A second feedback path communicates with the inverting input and the output of the amplifier. The first feedback path provides feedback at a lower frequency than the second feedback path. A first resistance has one end that communicates with the output of the amplifier. A first capacitance has one end that communicates with an opposite end of the load resistance. A second resistance has one end that communicates with the inverting input and an opposite end that communicates with the opposite end of the first resistance.
    Type: Grant
    Filed: February 24, 2011
    Date of Patent: July 31, 2012
    Assignee: Marvell International Ltd.
    Inventor: Farbod Aram
  • Publication number: 20120139627
    Abstract: An amplifier is provided that has a first loop interacting with a second loop. A feedback signal and input signal are provided to the amplifier. The first loop and the second loop interact with the input signal to nullify the feedback signal.
    Type: Application
    Filed: April 23, 2011
    Publication date: June 7, 2012
    Inventor: Mats Carlsson
  • Publication number: 20120068765
    Abstract: A method for offset compensation of a switched-capacitor amplifier comprises a reset phase (?1) and at least one working phase (?2). An output voltage (Vout) of the amplifier (amp) is fed according to a damped feedback loop gain (AB(1)) to a first amplifier input (ain1) in the reset phase (?1) as a function of an offset voltage (Voff). In the least one working phase (?2), an offset of the amplifier (amp) is compensated as a function of the offset voltage (Voff) by superimposing the output voltage (Vout) onto an input voltage (Vin) of the amplifier (amp) according to a loop gain (AB(2)).
    Type: Application
    Filed: August 24, 2011
    Publication date: March 22, 2012
    Applicant: austriamicrosystems AG
    Inventor: Vincenzo LEONARDO
  • Publication number: 20110193623
    Abstract: The present invention relates to a large time constant steering circuit for slowly changing a voltage on a node between at least two discrete voltage levels. The present invention further relates to a slow steering current DAC comprising said large time constant steering circuit. The present invention further relates to an instrumentation amplifier device comprising a current balancing instrumentation amplifier for amplifying an input signal to an amplified output signal and a DC servo-loop for removing a DC-component from the input signal. The present invention further relates to an EEG acquisition ASIC comprising said instrumentation amplifier device.
    Type: Application
    Filed: February 25, 2011
    Publication date: August 11, 2011
    Applicants: IMEC, KATHOLIEKE UNIVERSITEIT LEUVEN
    Inventors: Refet Firat Yazicioglu, Patrick Merken
  • Publication number: 20110169677
    Abstract: Two resistive elements and a capacitive element are coupled between a first node and each of an inverting input terminal of an operational amplifier, an output terminal of the operational amplifier, and a common node. A resistive element and a capacitive element are coupled between the first node and a signal input terminal. Two capacitive elements and a resistive element are coupled between a second node and each of the inverting input terminal, the output terminal, and the common node. Two capacitive elements are coupled between the second node and each of the signal input terminal, and the common node.
    Type: Application
    Filed: March 28, 2011
    Publication date: July 14, 2011
    Applicant: PANASONIC CORPORATION
    Inventors: Shiro DOSHO, Kazuo Matsukawa, Yosuke Mitani
  • Publication number: 20110163803
    Abstract: There is provided an integrated circuit having a programmable gain amplifier and an embedded filter. The programmable gain amplifier and the filter comprise a gain element having an inverting input for receiving an input and a feedback signal, a non-inverting input coupled to ground, and an output. The gain element also has one or more feedback loops coupling the output of the gain element to the inverting input of the gain element. Each feedback loop has a switch coupled in series with at least one passive component. Each switch has a first state to connect the corresponding feedback loop and a second state to disconnect the corresponding feedback loop. Each switch is programmatically configurable to provide a first gain and a first bandwidth and a second gain and a second bandwidth such that the first bandwidth is substantially equal to the second bandwidth.
    Type: Application
    Filed: January 6, 2010
    Publication date: July 7, 2011
    Inventors: Huimin Guo, Shuzuo Lou, Gang Qian, Wai Po Wong
  • Patent number: 7961043
    Abstract: In an amplifier arrangement comprising an amplifier (AO) having an output, a first feedback (Rfb) between the output and an input side of the amplifier, a load (RL) having a first terminal coupled to the output and a second terminal, and a DC-blocking capacitance (CDC) between the second terminal of the load and a reference terminal, a second feedback (Cx, Rx) is present between the second terminal of the load and the input side of the amplifier.
    Type: Grant
    Filed: January 5, 2007
    Date of Patent: June 14, 2011
    Assignee: NXP B.V.
    Inventor: Marco Berkhout
  • Patent number: 7920005
    Abstract: The present invention relates to a large time constant steering circuit for slowly changing a voltage on a node between at least two discrete voltage levels. The present invention further relates to a slow steering current DAC comprising said large time constant steering circuit. The present invention further relates to an instrumentation amplifier device comprising a current balancing instrumentation amplifier for amplifying an input signal to an amplified output signal and a DC servo-loop for removing a DC-component from the input signal. The present invention further relates to an EEG acquisition ASIC comprising said instrumentation amplifier device.
    Type: Grant
    Filed: January 30, 2009
    Date of Patent: April 5, 2011
    Assignees: IMEC, Katholieke Universiteit Leuven K.U., Leuven R&D
    Inventors: Refet Firat Yazicioglu, Patrick Merken
  • Publication number: 20110068864
    Abstract: An amplification device, comprising a device input receiving a device input signal, an amplifier unit comprising a zero crossing detector unit, an output filter and a lead-lag compensation network. The zero crossing detector unit compares the device input signal with a reference potential and switches a pulse width modulated detector output signal between first and second voltage levels dependent on the comparison. The amplifier unit provides an actual device output signal, e.g., an amplified representation of the device input signal. The amplification device further comprises a device output providing the actual device output signal, a control loop bridging the amplifier unit and comprising a forward filter, e.g., an integrating filter, for increasing loop gain improving the signal-to-noise ratio of the actual device output signal, and a deviation detection unit detecting over modulation of the amplifier unit, so that the amplification device disables forward filter functioning upon over modulation.
    Type: Application
    Filed: February 17, 2010
    Publication date: March 24, 2011
    Applicant: Hypex Electronics B.V.
    Inventor: Bruno Johan Georges Putzeys
  • Patent number: 7880543
    Abstract: A data transmitting circuit includes a reflection suppressive component generating circuit for generating a reflection suppressive component for suppressing the reflection caused by the discontinuity in the characteristic impedance on a transmission line, and a data output circuit for amplifying the reflection suppressive component and the data to be currently transmitted to a receiving side and outputting them to the transmission line.
    Type: Grant
    Filed: February 25, 2009
    Date of Patent: February 1, 2011
    Assignee: Fujitsu Limited
    Inventors: Hisakatsu Yamaguchi, Yoshiyasu Doi, Hirotaka Tamura
  • Patent number: 7855598
    Abstract: An electronic signal processor for processing signals includes a complex first filter, one or more gain stages and a second filter. The first filter is characterized by a frequency response curve that includes multiple corner frequencies, with some corner frequencies being user selectable. The first filter also has at least two user-preset gain levels which may be alternately selected by a switch. Lower frequency signals are processed by the first filter with at least 12 db/octave slope, and preferably with 18 db/octave slope to minimize intermodulation distortion products by subsequent amplification in the gain stages. A second filter provides further filtering and amplitude control. The signal processor is particularly suited for processing audio frequency signals.
    Type: Grant
    Filed: January 20, 2010
    Date of Patent: December 21, 2010
    Inventor: Jeffrey Arnold
  • Patent number: 7825735
    Abstract: A transimpedance amplifier system is disclosed which simultaneously generates a low-gain output signal and a high-gain output signal from an input current signal using a single transimpedance amplifier having two different feedback loops with different amplification factors to generate two different output voltage signals. One of the feedback loops includes a resistor, and the other feedback loop includes another resistor in series with one or more diodes. The transimpedance amplifier system includes a signal linearizer to linearize one or both of the low- and high-gain output signals by scaling and adding the two output voltage signals from the transimpedance amplifier. The signal linearizer can be formed either as an analog device using one or two summing amplifiers, or alternately can be formed as a digital device using two analog-to-digital converters and a digital signal processor (e.g. a microprocessor or a computer).
    Type: Grant
    Filed: October 20, 2009
    Date of Patent: November 2, 2010
    Assignee: Sandia Corporation
    Inventor: Kurt O. Wessendorf
  • Patent number: 7683710
    Abstract: An electronic signal processor for processing signals includes a complex first filter, one or more gain stages and a second filter. The first filter is characterized by a frequency response curve that includes multiple corner frequencies, with some corner frequencies being user selectable. The first filter also has at least two user-preset gain levels which may be alternately selected by a switch. Lower frequency signals are processed by the first filter with at least 12 db/octave slope, and preferably with 18 db/octave slope to minimize intermodulation distortion products by subsequent amplification in the gain stages. A second filter provides further filtering and amplitude control. The signal processor is particularly suited for processing audio frequency signals.
    Type: Grant
    Filed: May 23, 2008
    Date of Patent: March 23, 2010
    Inventor: Jeffrey Arnold
  • Patent number: 7633338
    Abstract: An amplifier circuit comprises a first capacitance having one end that communicates with an input of a first amplifier stage. An amplifier has a first gain, an input that communicates with an opposite end of the first capacitance, and an output. A second capacitance has a first end that communicates with the output of the amplifier and an opposite end that communicates with an input of a second amplifier stage. A broadband buffer has an input that communicates with the output of the amplifier and an output that communicates with the one end of the second capacitance.
    Type: Grant
    Filed: July 18, 2008
    Date of Patent: December 15, 2009
    Assignee: Marvell International, Ltd
    Inventor: Farbod Aram
  • Publication number: 20090284315
    Abstract: An operational amplifier includes, between an input and an output of an operational amplifier (an operational amplification stage) 10, a feedback capacitor 34 connected in negative feedback, a phase control circuit 100 having a resistor element (a resistor unit) 30 connected in series to the feedback capacitor 34. Load capacitors (load units) 32 are connected on the output side of the operational amplifier 10 and driven by an output signal from the operational amplifier 10. In a case that the capacitance values of the load capacitor 32 and 33 are increased and the phase margin of the operational amplifier becomes excessive in comparison with the optimum value, a resistance value RO of the resistor element 30 is increased to control the phase margin of the operational amplifier so as to fall within the optimum range, and thus accelerated settling properties are realized.
    Type: Application
    Filed: May 21, 2007
    Publication date: November 19, 2009
    Inventors: Satoshi Kobayashi, Junji Nakatsuka
  • Publication number: 20090224827
    Abstract: A circuit arrangement and method for improving load regulation in an amplifier (e.g., LDO amplifier) uses a feedback circuit including a parallely connected feedback resistance Rf and a noise reduction feedback capacitance Cf, wherein an external capacitance has equivalent series resistance (ESR). The circuit arrangement includes a resistance Resr in the amplifier output, a junction point of the feedback resistance Rf and the feedback capacitor Cf being connected to a negative input of the LDO amplifier. Additionally, the circuit arrangement might include a resistance Rintentional in between Cf and Rf. The circuit arrangement provides good load regulation and better stability without increase in power/area. The arrangement supports external feedback mode providing design flexibility without compromising amplifier-stability, which provides high output current drive capability or enables driving heavy output capacitance.
    Type: Application
    Filed: March 6, 2008
    Publication date: September 10, 2009
    Inventors: Preetam Charan Anand TADEPARTHY, Vikram Gakhar
  • Patent number: 7512387
    Abstract: A system for controlling a power supplied to a load from a radio frequency amplifier system includes a radio frequency signal generator adapted for generating a radio frequency signal, an amplifier to which the radio frequency signal is supplied and that amplifies the radio frequency signal into a radio frequency power signal, a power coupler connected to the amplifying member for coupling the radio frequency power signals, where the power coupler includes a summing connection adapted for connection to the load and a compensating connection adapted for connection to a dissipative element. A first control value generating member is adapted for receiving a signal proportional to a power output from the power coupler at the summing connection and is adapted for generating a first control signal for controlling the amplifier or a current supply that supplies current to the amplifier.
    Type: Grant
    Filed: May 17, 2005
    Date of Patent: March 31, 2009
    Assignee: Huettinger Elektronik GmbH + Co. KG
    Inventor: Michael Glueck
  • Publication number: 20080290937
    Abstract: Constant and accurate signal gain systems based on controlling oscillator loop gain. A constant gain positive feedback network and an amplifier form an oscillator. Only when the oscillator loop gain is at least one does the oscillator produces an AC signal. Negative feedback of the oscillator's AC signal level is used to keep the loop gain close to or at the value of one by controlling the loop gain of the oscillator circuit. By maintaining the loop gain of the oscillator circuit substantially constant the signal gain is also maintained substantially constant.
    Type: Application
    Filed: May 6, 2008
    Publication date: November 27, 2008
    Inventor: Fred A. Mirow
  • Patent number: 7403068
    Abstract: A method for double sampling loop negative feedback comprising: obtaining a low-frequency feedback signal from the output of the amplifier; obtaining a high-frequency feedback signal from part of the amplifier of which high-frequency phase shift is low, wherein two-ways sampling signals have the same amplifying phase; combining the two-ways sampling signals together using a series capacitor-inductor double signal combining circuit to form one signal, the signal having low phase shift at both high and low-frequency and being used for negative loop feedback. The invention also provides a double negative feedback amplifier using the method.
    Type: Grant
    Filed: August 10, 2005
    Date of Patent: July 22, 2008
    Inventor: Zongshan Zhou
  • Patent number: 7403067
    Abstract: An amplifier circuit comprises a first capacitance having one end that communicates with an input of a first amplifier stage. An amplifier has a first gain, an input that communicates with an opposite end of the first capacitance, and an output. A second capacitance has a first end that communicates with the output of the amplifier and an opposite end that communicates with an input of a second amplifier stage. A broadband buffer has an input that communicates with the output of the amplifier and an output that communicates with the one end of the second capacitance.
    Type: Grant
    Filed: December 2, 2005
    Date of Patent: July 22, 2008
    Assignee: Marvell International Ltd.
    Inventor: Farbod Aram
  • Publication number: 20080150631
    Abstract: A biosignal amplifying device includes: an operational amplifier (op-amp); a capacitor load including a first capacitor connected with a first input terminal of the op-amp, and in which a first voltage is inputted from a first electrode, and a second capacitor which is connected with a second input terminal of the op-amp, and in which a second voltage is inputted from a second electrode; a feedback capacitor load including a first feedback capacitor connected with the first input terminal and an output terminal, and a second feedback capacitor connected with the second input terminal; and a feedback resistor load including a first feedback resistor connected with the first input terminal and the output terminal, and a second feedback resistor connected with the second input terminal.
    Type: Application
    Filed: December 21, 2007
    Publication date: June 26, 2008
    Applicant: Samsung Electronics Co., Ltd.
    Inventors: Jong Pal Kim, Kun Soo Shin
  • Patent number: 7366427
    Abstract: A method and apparatus to provide bandwidth control in a high speed line driver circuit is described.
    Type: Grant
    Filed: June 22, 2004
    Date of Patent: April 29, 2008
    Assignee: Intel Corporation
    Inventor: Shenggao Li
  • Patent number: 7279970
    Abstract: For reducing various adverse effects due to provision of a low-pass filter, while suppressing an oscillation generated therein, there is provide a feedback circuit, having at least one operational amplifier, having a low-pass filter in an output portion thereof, for feeding a signal from the output portion back thereto, including: a first feedback circuit portion for negatively feeding a signal from an input terminal of the low-pass filter back to an inverted input terminal of the operational amplifier; and a second feedback circuit portion for negatively feeding a signal from an output terminal of the low-pass filter back to the inverted input terminal of the operational amplifier.
    Type: Grant
    Filed: August 10, 2005
    Date of Patent: October 9, 2007
    Assignee: Flying Mole Corporation
    Inventors: Kenji Yokoyama, Yasuo Yamada, Hiroshi Ogawa
  • Patent number: 7151405
    Abstract: Reducing a non-linearity effect of a power amplifier includes receiving signals at off-line inverse and forward models. The signals include an input signal, a pre-distorted signal, and an output signal. The output signal exhibits distortion with respect to the input signal, where the distortion includes an impairment effect and a non-linearity effect. The impairment effect is reduced in accordance with the signals. A memory depth of the power amplifier is estimated in accordance with the signals to generate memory information. Non-linearity of the power amplifier is estimated in accordance with the memory information. Pre-distortion information is calculated according to the estimated non-linearity. The non-linearity effect is reduced using the pre-distortion information.
    Type: Grant
    Filed: July 14, 2004
    Date of Patent: December 19, 2006
    Assignee: Raytheon Company
    Inventor: Mohamed K. Nezami
  • Patent number: 7061313
    Abstract: A dual feedback topology imparts stability to a multistage linear amplifier, particularly by improving overall amplifier phase margin at higher signal frequencies. With dual feedback, an inner feedback loop is closed around the first amplifier stage, which stage is configured as a current feedback amplifier. A second feedback loop is closed around the overall multistage amplifier. With a current feedback amplifier as the initial stage, the two feedback signals are current-mode signals and thus add to form the combined feedback signal. The frequency responses of the inner and outer feedback loops may be tailored for flat frequency response, or, where desired, may be adjusted to compensate or otherwise flatten overall amplifier frequency response.
    Type: Grant
    Filed: January 23, 2002
    Date of Patent: June 13, 2006
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Donald Felt Kimball, Joseph L. Archambault, Walter Haley, Lennart Mathe
  • Patent number: 7053705
    Abstract: A method and system for providing a mixed-mode (current- and voltage-source) audio amplifier is disclosed. The mixed-mode amplifier includes a voltage sensing feedback path including a first network comprising at least one circuit; and a current sensing feedback path including a second network comprising at least one circuit. According to the method and system disclosed herein, the first and second networks vary an output impedance or transconductance of the amplifier as a function of frequency of the input voltage signal, such that at a first frequency range, the amplifier operates substantially as a current amplifier, and at a second frequency range, the amplifier operates substantially as a voltage amplifier, thereby inheriting distortion reduction of the current amplifier and stability of the voltage amplifier.
    Type: Grant
    Filed: December 23, 2003
    Date of Patent: May 30, 2006
    Assignee: Tymphany Corporation
    Inventors: John J. Hench, Joseph Comparetto
  • Patent number: 7012466
    Abstract: A load responds to a voltage-to-current converter including a differential amplifier. A sensing resistor is series connected with the load and first and second feedback resistors, respectively included in first and second voltage dividers having taps connected to non-inverting and inverting inputs of the amplifier. One divider is connected between a first terminal of the sensor resistor and one voltage responsive input terminal of the converter. Another divider is connected between the second terminal of the sensor resistor and a second converter input terminal, that can be grounded or voltage responsive. The feedback resistors have the same value that is much greater than the sensor resistor value. The first divider can be connected to the first or second terminal of the sensor resistor and vice versa for the second divider.
    Type: Grant
    Filed: February 5, 2004
    Date of Patent: March 14, 2006
    Inventor: Mauro Cerisola
  • Patent number: 7010284
    Abstract: A multi-stage amplifier is coupled with a power detector. The multi-stage amplifier includes a plurality of amplifier stages in series, with a signal path extending through them. The power detector is coupled to an interior node of the amplifier along the signal path, and is operable to sample a first signal being transmitted on the signal path. The power detector outputs a second signal reflective of a power of the first signal. In one embodiment, the interior node is in a matching network of the amplifier disposed between a first amplifier stage and a final amplifier stage of the amplifier. The second signal may be used in a feedback network to adjust an amount of amplification of the first signal by the amplifier.
    Type: Grant
    Filed: June 10, 2003
    Date of Patent: March 7, 2006
    Assignee: TriQuint Semiconductor, Inc.
    Inventors: Li Liu, Christopher C. Souchuns, Ping Li, Gregory N. Henderson
  • Patent number: 7002409
    Abstract: A compensation circuit is provided for an amplifier including at least first and second amplifier stage. The circuit includes a first capacitance including one end that communicates with an input of the first amplifier stage. An amplifier includes a first gain, an input that communicates with an opposite end of the first capacitance, and an output. A second capacitance includes a first end that communicates with the output of the amplifier and an opposite end that communicates with an input of the second amplifier stage. A first impedence includes one end that communicates with the input of the first amplifier stage and an opposite end that communicates with an output of the second amplifier stage.
    Type: Grant
    Filed: February 11, 2004
    Date of Patent: February 21, 2006
    Assignee: Marvell International Ltd.
    Inventor: Farbod Aram
  • Patent number: 6946910
    Abstract: A configurable feedback path is included in an amplitude control system having a signal source and an amplitude controller, and provides accurate tracking between a signal provided at a test port and a reference signal, whether or not the configurable feedback path is in an internally-leveled configuration or an externally-leveled configuration. The configurable feedback path includes a series of access ports, a detector that has an input coupled to the first access port, a filtered output coupled to the amplitude controller, and an unfiltered output providing the reference signal. The configurable feedback path also includes a signal separator that has an input terminal coupled to the signal source, a thru-terminal coupled to the third access port, and a coupled terminal that is coupled to the second access port. The fourth access port is coupled to the test port.
    Type: Grant
    Filed: August 29, 2002
    Date of Patent: September 20, 2005
    Assignee: Agilent Technologies, Inc.
    Inventor: Chen-Yu Chi
  • Patent number: 6825718
    Abstract: The present invention discloses an impedance matching circuit which is suitable to be applied on an IC chip. The impedance matching circuit comprises a resistor unit, an OP amplifier circuit connected with the resistor unit, a feedback selecting circuit connected in parallel with the OP amplifier circuit, and a resistor selecting circuit connected with both the OP amplifier circuit and the feedback selecting circuit. The feedback selecting circuit further includes a plurality of switching circuits for enabling some of the resistors furnished in the resistor selecting circuit. By selecting and actuating one of the switching circuits, some certain resistors will be enabled so as to adjust the resistance value of the resistor selecting circuit. The resistor unit and the switching circuits are designed in such a manner that the resistor unit is able to compensate an equivalent resistance of the switching circuit which is actuated.
    Type: Grant
    Filed: June 19, 2003
    Date of Patent: November 30, 2004
    Assignee: Realtek Semiconductor Corp.
    Inventors: Tzung-Hung Kang, Chao-Cheng Lee
  • Patent number: 6646463
    Abstract: A method and device to emulate impedances includes a pair of impedances connected in series between two circuit nodes, the impedances forming a voltage divider having at its midpoint a reference voltage VX. An OP AMP includes a positive input connected to the VX—node and the negative input connected to the output thereof in a direct feedback loop. The OP AMP output is also connected to a load impedance that is connected either one of the nodes. A transistor may be interposed between the load impedance and the circuit node. The OP AMP may be provided with a negative gain to emulate an inductor. The voltage divider may be variable to emulate a variable impedance.
    Type: Grant
    Filed: February 22, 2002
    Date of Patent: November 11, 2003
    Assignee: Alliance Semiconductor
    Inventor: Dan Ion Hariton
  • Patent number: 6600367
    Abstract: An electronic amplifier providing very low distortion which includes an output stage with an output error correction stage containing two amplifiers and wherein there are at least four local negative feedback paths, an output of the first amplifier being connected to an input of output stage transistor buffers or output stage transistors through a first network, an output of the second amplifier being connected to an input of output stage transistor buffers or output stage transistors through a second network, where components of the first and second amplifier the local negative feedback paths, first and second networks and output stage transistor buffers are selected to form substantially second order local dominant pole. Also disclosed is the supply of power to said first and second amplifiers from a floating power supply means coupled to either an or the output of the output stage so that the voltage of the floating power supply will follow substantially an output voltage of the output stage.
    Type: Grant
    Filed: July 24, 2001
    Date of Patent: July 29, 2003
    Assignee: BHC Consulting Pty Ltd.
    Inventor: Bruce Halcro Candy