Current And Voltage Feedback Patents (Class 330/102)
  • Patent number: 9954490
    Abstract: An amplifier circuitry for an envelope modulator including: a linear amplifier configured to receive an input representing an envelope of a signal to be amplified; a charge storage device coupled to the amplifier for providing an amplified envelope signal for driving a load, the amplifier and charge storage device configured to receive a supply voltage; wherein the amplifier circuitry is configured such that responsive to the voltage of the input envelope signal reaching or exceeding a defined threshold value, an input voltage based on the voltage of the received envelope signal is provided to the amplifier to enable the charge storage device to supply a charge above the supply voltage such that the output voltage of the load driven by the amplifier circuitry is increased above the supply voltage. An envelope modulator incorporates the modulator and a method for amplifying an envelope signal utilizes the modulator.
    Type: Grant
    Filed: March 27, 2014
    Date of Patent: April 24, 2018
    Assignee: KABUSHIKI KAISHA TOSHIBA
    Inventor: Gavin Watkins
  • Patent number: 9647614
    Abstract: A power amplifier includes a class D amplification section and a load current feedback circuit. The class D amplification section includes an input section and a switching section serving as an output stage and switched depending on a signal input to the input section, and outputs current from a power source to a load via the switching section. The load current feedback circuit negatively feeds back the current flowing in the load to the input section of the class D amplification section.
    Type: Grant
    Filed: July 17, 2015
    Date of Patent: May 9, 2017
    Assignee: Yamaha Corporation
    Inventors: Yohei Otani, Masao Noro
  • Patent number: 9590568
    Abstract: A power amplifier includes a class D amplification section and a load current feedback circuit. The class D amplification section includes an input section and a switching section serving as an output stage and switched depending on a signal input to the input section, and outputs current from a power source to a load via the switching section. The load current feedback circuit negatively feeds back the current flowing in the load to the input section of the class D amplification section.
    Type: Grant
    Filed: July 17, 2015
    Date of Patent: March 7, 2017
    Assignee: Yamaha Corporation
    Inventors: Yohei Otani, Masao Noro
  • Patent number: 9490870
    Abstract: In accordance with an embodiment, a sender circuit is configured to be coupled to a receiver circuit and generate a drive signal dependent on a data input signal received by the sender circuit at a first input and dependent on at least one drive signal generation parameter. The sender circuit is further configured to adjust the at least one drive signal generation parameter dependent on a feedback signal received at a second input.
    Type: Grant
    Filed: January 17, 2014
    Date of Patent: November 8, 2016
    Assignee: Infineon Technologies Austria AG
    Inventors: Marcus Nuebling, Jens Barrenscheen
  • Patent number: 8729964
    Abstract: A power envelope controller configured for use with an amplification stage and method are disclosed. The power envelope controller includes voltage feedback input circuitry configured to receive a voltage feedback signal representing an internal voltage drop across the amplification stage and current feedback input circuitry configured to receive a current feedback signal representing an output current of the amplification stage. An analog multiplier is configured to generate an internal power dissipation signal representing the internal power dissipation of the amplification stage based on the voltage and current feedback signals. A comparator circuit is configured to compare the internal power dissipation signal to a power threshold and generate a power control error signal when the internal power dissipation of the amplification stage exceeds the threshold.
    Type: Grant
    Filed: July 13, 2012
    Date of Patent: May 20, 2014
    Assignee: Keithley Instruments, Inc.
    Inventor: Martin J. Rice
  • Patent number: 8410856
    Abstract: The noise figure of a low noise amplifier (LNA) is reduced without sacrificing performance such as gain, IIP3, and wideband impedance matching. Embodiments include configuring a control module of the LNA to sum and scale an output from a current-sensing branch of the LNA and an output from a voltage sensing branch of the LNA into one or more summed and scaled outputs. The control module also feeds the one or more summed and scaled outputs back to at least one of the outputs of the branches of the LNA.
    Type: Grant
    Filed: December 17, 2010
    Date of Patent: April 2, 2013
    Assignee: Industrial Technology Research Institute
    Inventors: Ming-Ching Kuo, Yi-Shing Shih, Shih-Hao Tarng
  • Patent number: 8378746
    Abstract: A voltage-mode line driving circuit is provided. The voltage-mode line driving circuit includes a driving circuit, the driving circuit receiving, as an input signal, a feedback signal, and outputting an output signal. The voltage-mode line driving signal also includes an adaptive tuning circuit coupled to the driving circuit, the adaptive tuning circuit receiving as input signals the feedback signal and the output signal and adaptively outputting a modifying signal to the driving circuit which modifies the feedback signal.
    Type: Grant
    Filed: July 11, 2008
    Date of Patent: February 19, 2013
    Assignee: Integrated Device Technology, inc
    Inventors: Xuexin Ding, Zhongyuan Chang
  • Publication number: 20120133634
    Abstract: An amplifier, electronic display system, and a related method for generating a low power signal with an operational amplifier are disclosed herein. An embodiment of the present invention includes an amplifier, comprising an operational amplifier and a voltage converter. The operational amplifier includes an inverting input, a non-inverting input, an output, a first power supply input and a second power supply input, and is configured to generate an output signal in response to an input signal. The voltage is operably coupled with the first power supply input of the operating amplifier, and is configured to receive a first supply voltage and generate a second supply voltage to the first power supply input of the operational amplifier. The voltage of the second supply voltage is relatively closer to the expected operating voltage range of the output signal than is the first supply voltage.
    Type: Application
    Filed: November 30, 2010
    Publication date: May 31, 2012
    Applicant: INTEGRATED DEVICE TECHNOLOGY, INC.
    Inventors: June Her, Andrew Luchsinger, Marc Kobayashi, Paul Brokaw
  • Publication number: 20110140773
    Abstract: In one embodiment, the present disclosure includes a circuit comprising an amplifier having an input and an output, an offset detection circuit to detect an offset of the amplifier at the output of the amplifier, and an offset generation circuit having an input coupled to the offset detection circuit and an output coupled to the input of the amplifier to generate an offset at the input of the amplifier during an operational phase of the amplifier based on the detected offset. The generated offset cancels a least a portion of the offset of the amplifier. In one implementation, the amplifier is a sense amplifier in a memory.
    Type: Application
    Filed: December 6, 2010
    Publication date: June 16, 2011
    Inventors: Winston Lee, Peter Lee
  • Patent number: 7804364
    Abstract: A method and apparatus is provided for detecting the output power of a power amplifier. The output power is detected by detecting the absolute values of the voltage and current at the output of the amplifier and mixing the detected voltage and current to generate a signal related to the output power.
    Type: Grant
    Filed: December 22, 2004
    Date of Patent: September 28, 2010
    Assignee: Black Sand Technologies, Inc.
    Inventors: Timothy J. Dupuis, David R. Welland, Susanne A. Paul, Ali M. Niknejad
  • Patent number: 7688136
    Abstract: In some embodiments, a circuit includes a power amplifier including an input terminal configured to receive an input signal and an output terminal to provide an RF voltage, the output terminal coupled to a load, a current sensor configured to sense the current drawn by the power amplifier and provide a first sensor output signal dependent upon current consumption when the current exceeds a predetermined current threshold, a voltage sensor configured to sense the output power of the power amplifier and provide a second sensor output signal when the RF voltage during up ramp falls below a predetermined threshold voltage, and a summing circuit configured to receive the first and second sensor output signals and provide a feedback signal including a combination of a power dependent contribution and either of a voltage dependent contribution or a current dependent contribution.
    Type: Grant
    Filed: January 23, 2009
    Date of Patent: March 30, 2010
    Assignee: Infineon Technologies AG
    Inventors: Andreas Langer, Andrea Camuffo
  • Patent number: 7557653
    Abstract: In some embodiments, a circuit includes a power amplifier including an input terminal configured to receive an input signal and an output terminal to provide an RF voltage, the output terminal coupled to a load, a current sensor configured to sense the current drawn by the power amplifier and provide a first sensor output signal dependent upon current consumption when the current exceeds a predetermined current threshold, a voltage sensor configured to sense the output power of the power amplifier and provide a second sensor output signal when the RF voltage during up ramp falls below a predetermined threshold voltage, and a summing circuit configured to receive the first and second sensor output signals and provide a feedback signal including a combination of a power dependent contribution and either of a voltage dependent contribution or a current dependent contribution.
    Type: Grant
    Filed: October 22, 2007
    Date of Patent: July 7, 2009
    Assignee: Infineon Technologies AG
    Inventors: Andrea Camuffo, Andreas Langer
  • Patent number: 7525376
    Abstract: A power amplifier to provide a compensated output voltage to a load through a series-connected impedance. The power amplifier includes an inner positive current feedback loop that is capable of sensing changes in the resistance of the load, and which adjusts the effective impedance of the series-connected impedance seen by the load to reduce current induced changes in the level of the compensated output voltage provided to the load due to the presence of the series connected impedance.
    Type: Grant
    Filed: July 10, 2007
    Date of Patent: April 28, 2009
    Assignee: Asterion, Inc.
    Inventor: Donald H. Boughton, Jr.
  • Patent number: 7511565
    Abstract: An integrated circuit comprises a gain stage circuit coupled to a compensation circuit. Both the gain stage circuit and the compensation circuit respectively comprise a first current source and a second current source that are subject to the same process variations. A negative feedback circuit is used to generate a corrective current in relation to the second current source, indicative of a current that needs to flow through a load in addition to a current flowing through the second current source in order for a variable voltage to be substantially equal to a reference voltage used to drive the first and second current sources. A compensating current corresponding to the corrective current generated for the second current source is applied to the first current source to compensate for process variation in the gain stage circuit in respect to the first current source.
    Type: Grant
    Filed: June 19, 2006
    Date of Patent: March 31, 2009
    Assignee: Avago Technologies General IP (Singapore) Pte. Ltd.
    Inventors: Fesseha Tessera Seifu, Marco Fornasari, Samir Aboulhouda
  • Patent number: 7501860
    Abstract: A differential input driver circuit (10, 50) includes first and second transistors (Q0, Q3) as input transistors and third and fourth transistors (Q1, Q2) as diode-connected, cross-coupled transistors. In one embodiment, first, second, third and fourth transistors are NPN bipolar transistors. The base terminals of the first and third transistors are connected while the base terminals of the second and fourth transistors are connected. The input transistors receive a pair of differential input signals (In+/?) at the emitter terminals (24, 26) and provides a pair of differential output signals (Vo+/?) at the collector terminals (16, 18). The emitter terminals of the diode-connected transistors (Q1, Q2) couple the input signal at the emitter terminal of the first transistor to the collector terminal of the second transistor and vice versa. The cross-coupling of the third and fourth transistors enables the input driver to operate effectively in single-ended to differential conversion mode.
    Type: Grant
    Filed: December 3, 2007
    Date of Patent: March 10, 2009
    Assignee: National Semiconductor Corporation
    Inventors: Andrew Fitting, Michael Maida
  • Patent number: 7486137
    Abstract: An architecture for detecting amplifier power is provided. The architecture includes a voltage envelope detector that receives a voltage signal and generates a voltage envelope signal. A current envelope detector receives a current signal and generates a current envelope signal. A power amplifier level controller receives the greater of the voltage envelope signal and the current envelope signal, such as by connecting the output of the voltage envelope detector and the current envelope detector at a common point and conducting the high frequency current components to ground via a capacitor. A power amplifier level control signal is then generated based on the voltage drop across the capacitor.
    Type: Grant
    Filed: January 18, 2007
    Date of Patent: February 3, 2009
    Assignee: Axiom Microdevices, Inc.
    Inventors: Rahul Magoon, Ichiro Aoki, John Lyu, Scott Kee, Roberto Aparico Joo
  • Publication number: 20080186092
    Abstract: In some embodiments, a circuit includes a power amplifier including an input terminal configured to receive an input signal and an output terminal to provide an RF voltage, the output terminal coupled to a load, a current sensor configured to sense the current drawn by the power amplifier and provide a first sensor output signal dependent upon current consumption when the current exceeds a predetermined current threshold, a voltage sensor configured to sense the output power of the power amplifier and provide a second sensor output signal when the RF voltage during up ramp falls below a predetermined threshold voltage, and a summing circuit configured to receive the first and second sensor output signals and provide a feedback signal including a combination of a power dependent contribution and either of a voltage dependent contribution or a current dependent contribution.
    Type: Application
    Filed: October 22, 2007
    Publication date: August 7, 2008
    Applicant: Infineon Technologies AG
    Inventors: Andrea Camuffo, Andreas Langer
  • Patent number: 7369816
    Abstract: A radio transceiver includes circuitry that enables received RF signals to be down-converted to baseband frequencies and baseband signals to be up-converted to RF signals prior to transmission without requiring conversion to an intermediate frequency. The circuitry includes a temperature sensing module that produces accurate voltage level readings that may be mapped into corresponding temperature values. A processor, among other actions, adjusts gain level settings based upon detected temperature values. One aspect of the present invention further includes repetitively inverting voltage signals across a pair of semiconductor devices being used as temperature sensors to remove a common mode signal to produce an actual temperature-voltage curve. In one embodiment of the invention, the circuitry further includes a pair of amplifiers to facilitate setting a slope of the voltage-temperature curve.
    Type: Grant
    Filed: August 6, 2004
    Date of Patent: May 6, 2008
    Assignee: Broadcom Corporation
    Inventors: Michael Steven Kappes, Arya Reza Behzad
  • Patent number: 7202742
    Abstract: A digital amplification device has a digital amplifying unit, a low-pass filter for integrating a digital signal, and a current feedback circuit that is transformer-coupled to the low-pass filter and feeds back current to the differential input terminal. A signal related to distortion is fed back and the distortion is reduced.
    Type: Grant
    Filed: July 25, 2003
    Date of Patent: April 10, 2007
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventor: Toshiya Nakagaki
  • 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: 6975734
    Abstract: An audio apparatus is constructed for use in negative drive of a loudspeaker having an internal impedance to perform a desired amplitude-frequency characteristic. In the audio apparatus, an amplifier device drives the loudspeaker with a driving voltage. A feedback device performs a positive feedback of a signal corresponding to the driving voltage of the loudspeaker to the amplifier device with a variable feedback gain, thereby causing the amplifier device to generate a negative impedance effective to negate the internal impedance of the loudspeaker. An adjustment device decreases the variable feedback gain of the feedback device as a level of the driving voltage of the loudspeaker increases, thereby adjusting the amplitude-frequency characteristic of the amplifier device.
    Type: Grant
    Filed: December 23, 1999
    Date of Patent: December 13, 2005
    Assignee: Yamaha Corporation
    Inventor: Eiichi Suzuki
  • Patent number: 6917245
    Abstract: A method and apparatus is provided for detecting the output power of a power amplifier. The output power is detected by detecting the absolute values of the voltage and current at the output of the amplifier and mixing the detected voltage and current to generate a signal related to the output power.
    Type: Grant
    Filed: March 13, 2002
    Date of Patent: July 12, 2005
    Assignee: Silicon Laboratories, Inc.
    Inventors: Timothy J. Dupuis, David R. Welland, Susanne A. Paul, Ali M. Niknejad
  • Patent number: 6756849
    Abstract: A method and apparatus is provided for detecting the output power of a power amplifier. The output power is detected by detecting the absolute values of the voltage and current at the output of the amplifier and mixing the detected voltage and current to generate a signal related to the output power.
    Type: Grant
    Filed: September 29, 2003
    Date of Patent: June 29, 2004
    Inventors: Timothy J. Dupuis, David R. Welland, Susanne A. Paul, Ali M. Niknejad
  • Patent number: 6130582
    Abstract: An amplifier circuit (14') for canceling variations in an amplifier feedback signal includes compensation circuitry (50) defining a replica of the feedback current therethrough. The replicated feedback current is drawn from a circuit node (N1) which directs the feedback signal to a differential pair (Q1, Q2) of the amplifier circuit 14', whereby any biasing effects on the differential pair (Q1, Q2) due to changes in the feedback signal resulting from changes in a gate drive output voltage (V.sub.GD) of the amplifier circuit (14') are eliminated. Accordingly, the gate drive output voltage (V.sub.GD) may be used to control an ignition coil (L1) drive transistor (16) whereby any changes in gate drive voltage (V.sub.GD) will not cause the coil current (I.sub.L) to deviate from its target coil current limit value.
    Type: Grant
    Filed: December 4, 1998
    Date of Patent: October 10, 2000
    Assignee: Delco Electronics Corporation
    Inventor: Scott Birk Kesler
  • Patent number: 5815040
    Abstract: A wide bandwidth, multi-FET current sharing output stage, MOS audio power amplifier employs multiple feedback loops. An audio input is supplied to a voltage feedback amplifier stage driving a push-pull voltage gain/phase splitter stage. A bias adjustment stage driven from the push-pull voltage gain/phase splitter stage drives a current drive stage. The current drive stage drives an output stage comprising a plurality of paralleled current shared individual MOS output transistors driving an output node connected to a load. Up to three feedback loops are employed. A first voltage feedback loop comprises a voltage feedback stage having an input connected to a voltage divider driven from the first terminal of the load and an output connected to a feedback input node in the voltage feedback amplifier stage.
    Type: Grant
    Filed: December 30, 1996
    Date of Patent: September 29, 1998
    Assignee: Anthony T. Barbetta
    Inventor: Anthony T. Barbetta
  • Patent number: 5761316
    Abstract: This disclosure shows the solid state emulation of elements of a thermionic emission device amplifier which distinguish it from solid state amplifiers: the output impedance of transformer impedance with plate resistance, the transfer function coupling from the driver tube to the output tubes, the non-linearity of the output tubes, the compression created by the power supply droop, the inclusion of "fat" from the power supply, bias shifting of the input, and driving the input from a non-linear network. This disclosure also depicts advantageous features not found in tube amplifiers: a means for turning it down and maintaining the tone by maintaining the interrelationships within the amplifier and fat creation from the amplifier output and from external sources. This disclosure is based upon the novel use of controlled gain and controlled impedance means.
    Type: Grant
    Filed: February 27, 1996
    Date of Patent: June 2, 1998
    Inventor: Eric K. Pritchard
  • Patent number: 5761317
    Abstract: This disclosure shows the solid state emulation of elements of a thermionic emission device amplifier which distinguish it from solid state amplifiers: the output impedance of transformer impedance with plate resistance, the transfer function coupling from the driver tube to the output tubes, the non-linearity of the output tubes, the compression created by the power supply droop, the inclusion of "fat" from the power supply, bias shifting of the input, and driving the input from a non-linear network. This disclosure also depicts advantageous features not found in tube amplifiers: a means for turning it down and maintaining the tone by maintaining the interrelationships within the amplifier and fat creation from the amplifier output and from external sources. This disclosure is based upon the novel use of controlled gain and controlled impedance means.
    Type: Grant
    Filed: March 4, 1996
    Date of Patent: June 2, 1998
    Inventor: Eric K. Pritchard
  • Patent number: 5719526
    Abstract: A load monitor module for measuring voltage and current supplied from an amplifier to a load is provided within an amplifier and includes a device for calculating an impedance of the load and an amount of power delivered to the load from the amplifier. The load monitor module includes a voltage measuring device and a current measuring device for accurately measuring the voltage and current of a generated test signal or an audio signal input the amplifier signal path without substantially altering the signal. The monitor module also includes a controller for controlling the performance of the amplifier and load according to the calculated load impedance and power input to the load from the amplifier.
    Type: Grant
    Filed: November 16, 1995
    Date of Patent: February 17, 1998
    Assignee: Crest Audio, Inc.
    Inventor: Dennis Fink
  • Patent number: 5382919
    Abstract: A family of wideband amplifier circuits using series and shunt feedback over two stages to achieve constant impedance, including single-ended, single-ended input/differential output and differential input/differential output forms.
    Type: Grant
    Filed: October 20, 1993
    Date of Patent: January 17, 1995
    Assignee: Plessey Semiconductors Limited
    Inventor: Rodney J. Lawton
  • Patent number: 5245296
    Abstract: An audio amplifier circuit which improves the efficiency, performance and power in a loudspeaker system. The circuit includes a discriminator differential amplifier which senses the motional voltage from the moving coil of a loudspeaker. The output signal from the differential amplifier is processed by the circuit into a correction voltage which is combined with the drive voltage and applied to the input of the loudspeaker.
    Type: Grant
    Filed: July 10, 1992
    Date of Patent: September 14, 1993
    Inventors: Francis A. Miller, Steven D. Heidorn
  • Patent number: 4897610
    Abstract: Negative-feedback amplifier provided with an active amplifier section operating approximately as a nullor and a negative feedback section, the amplifier having a high loop gain. The active amplifier section is constructed in balanced form with two nullors connected in balance, and the negative-feedback section is composed of passive impedances and comprises two negative-feedback loops. In one embodiment each nullor has a series-coupling circuit and a parallel-coupling circuit at the input port. As a result an accurately defined or characteristic input impedance is obtained, and a series- or parallel-coupling circuit is formed in both negative-feedback loops at the output port, so that a high (current output) or low (voltage output) output impedance, respectively is obtained. In another embodiment each nullor has a series-coupling circuit and a parallel-coupling circuit at the output port.
    Type: Grant
    Filed: April 28, 1988
    Date of Patent: January 30, 1990
    Assignee: Stichting Voor De Technische Wetenschappen
    Inventor: Paulus T. M. Van Zeijl
  • Patent number: 4758798
    Abstract: An amplifier system providing the voltage feedback which can be supplemented with current feedback without limiting the voltage excursion range at the amplifier system output.
    Type: Grant
    Filed: April 10, 1987
    Date of Patent: July 19, 1988
    Assignee: Cross Technology, Inc.
    Inventor: William A. Johnson
  • Patent number: 4628275
    Abstract: An efficient power amplifier for high-capacitive device C2 in load string 10. The load string 10 includes a reference capacitor C3, a resistor R1, and an inductor L1. A large capacitor C1 is connected to load string 10 through high voltage power bridge 28. A current sensing feedback 30 is utilized to produce a triangular waveform of current in load string 10 for causing charge to be alternatively removed from capacitor C1 and delivered to device C2 through inductor L1 and then returned to capacitor C1 with any losses replenished by the dc power source. A voltage sensing feedback 14 is used to modulate the triangular current waveform. The power amplifier behaves as a stable linear dc coupled operational amplifier delivering a large reactive current with only slight losses.
    Type: Grant
    Filed: July 29, 1985
    Date of Patent: December 9, 1986
    Assignee: Rockwell International Corporation
    Inventors: John D. Skipper, Steven M. Long
  • Patent number: 4611179
    Abstract: A wide-band type high-frequency amplifier circuit characterized in that a voltage feedback circuit is connected across a base and a colletor of an amplifier transistor, a current feedback circuit is inserted into an emitter circuit, and a damper resistance and a condenser having a small capacity are connected to a balun transformer of a collector circuit in parallel.
    Type: Grant
    Filed: June 5, 1985
    Date of Patent: September 9, 1986
    Assignee: Sharp Kabushiki Kaisha
    Inventor: Syuuji Matsuura
  • Patent number: 4590434
    Abstract: An amplifier uses non-dissipative elements to provide current and voltage feedback. The base amplifier has two input terminals, and the current and voltage feedback signals are applied to respective input terminals. The non-dissipative elements may be either transformers or coupled-line pairs. These elements allow broad band operation with low noise. The feedback configuration results in higher input impedence.
    Type: Grant
    Filed: May 6, 1983
    Date of Patent: May 20, 1986
    Assignee: New England Microwave Corporation
    Inventor: Walter D. Wagner
  • Patent number: 4393353
    Abstract: A negative feedback amplifying circuit comprises an amplifier connected to a load, a voltage negative feedback circuit which negatively feeds back the output voltage of the amplifier to the input side of the amplifier maintaining a frequency selection characteristic, and a current negative feedback circuit which negatively feeds back a current signal obtained by detecting the current flowing through the load to the input side of the amplifier maintaining a frequency selection characteristic. The voltage negative feedback circuit has a frequency selection characteristic comprising a dip at a specific frequency f.sub.0. On the other hand, the current negative feedback circuit has a frequency characteristic comprising a peak at a specific frequency f.sub.0.
    Type: Grant
    Filed: September 26, 1980
    Date of Patent: July 12, 1983
    Assignee: Victor Company of Japan, Ltd.
    Inventor: Hiroyasu Minagawa
  • Patent number: 4302726
    Abstract: A current source in which the output current from an output amplifier stage (2) is controlled by an input signal, originating in a signal source (11), to an input amplifier stage (1) incorporates, additionally to a negative feedback path from the current input path of the output stage (2) to the input amplifier (1), monitoring means (5) in the signal input path to the output amplifier (2) and control means (4) in an input path to the input amplifier (1). Monitoring means (5) monitors the current flow in the input path to the output amplifier (2) and applies, via control means (4) a signal to the input amplifier (1) such that the dependence of the current flow in the current output path on the gain of the output stage (2) is reduced. A circuit is described, as well as an application to driving a telephone subscriber line and using two current sources working in push-pull mode.
    Type: Grant
    Filed: July 10, 1979
    Date of Patent: November 24, 1981
    Assignee: The General Electric Company Limited
    Inventor: David E. Shobbrook
  • Patent number: 3972002
    Abstract: Current and voltage feedback are used in separate frequency dependent major loops around a high gain broadband amplifier to produce frequency shaped gain and matched input and output impedances.
    Type: Grant
    Filed: December 30, 1974
    Date of Patent: July 27, 1976
    Assignee: Bell Telephone Laboratories, Incorporated
    Inventor: Thomas Joseph Aprille, Jr.
  • Patent number: 3938057
    Abstract: A telecommunications signal amplifier comprising an active tripole the transfer function of which has a negative real portion, the input impedance and the output impedance of which are substantially equal to one another and to the iterative impedance of the line in which the amplifier according to the invention is inserted, a first dipole of defined structure, a second dipole of structure reciprocal to the first with respect to the iterative impedance of the circuit in which the amplifier according to the invention is inserted, characterised in that said signal amplifier is reduced to a tripole by merging an input terminal and an output terminal, the other input terminal is connected to a terminal of said first dipole and to an input terminal of said tripole, the other output terminal is connected to the other terminal of said first dipole and to an output terminal of said tripole, the common input and output terminal of this tripole being joined, by means of said second dipole, to the common input and output
    Type: Grant
    Filed: March 26, 1973
    Date of Patent: February 10, 1976
    Assignee: Societe Anonyme de Telecommunications
    Inventor: Pierre Jean Marie Minot