Power Or Bias Supply Circuits And Control Thereof Patents (Class 330/123)
  • Patent number: 10026375
    Abstract: An output amplifier of a source driver and a control method thereof are provided. The output amplifier includes a first switch circuit, a second switch circuit, a third switch circuit, a first input stage circuit, a second input stage circuit, a first active load circuit, a second active load circuit, a first positive output stage circuit, a first negative output stage circuit, a second positive output stage circuit and a second negative output stage circuit. In a first display stage of the control method, the first switch circuit outputs a positive reference signal through a first output terminal and outputs a negative reference signal through a second output terminal. In a second display stage of the control method, the signals outputted by the first output terminal and the second output terminal are exchanged.
    Type: Grant
    Filed: November 21, 2016
    Date of Patent: July 17, 2018
    Assignee: HIMAX TECHNOLOGIES LIMITED
    Inventors: Jia-Hui Wang, Chuan-Chien Hsu, Hung-Yu Huang
  • Patent number: 10013936
    Abstract: The present invention relates to a technology for outputting a gamma voltage in a source driver of a display device. A gamma voltage generation circuit of a source driver in accordance with the present invention may form wide high and low gamma voltage ranges even when a negative power supply voltage and a positive power supply voltage are asymmetrical to each other.
    Type: Grant
    Filed: October 23, 2014
    Date of Patent: July 3, 2018
    Assignee: SILICON WORKS CO., LTD
    Inventors: Yong Sung Ahn, Jung Min Choi
  • Patent number: 9728378
    Abstract: In one embodiment, an RF generator includes an RF amplifier comprising an RF input, a DC input, and an RF output, the RF amplifier configured to receive at the RF input an RF signal from an RF source; receive at the DC input a DC voltage from a DC source; and provide an output power at the RF output; and a control unit operably coupled to the DC source and the RF source, the control unit configured to receive a power setpoint indicative of a desired output power at the RF output; determine a power dissipation at the RF generator; alter the DC voltage to decrease the power dissipation at the RF generator; and alter the RF signal to enable the output power at the RF output to be substantially equal to the power setpoint.
    Type: Grant
    Filed: July 29, 2016
    Date of Patent: August 8, 2017
    Inventors: Imran Ahmed Bhutta, Tomislav Lozic
  • Patent number: 9666143
    Abstract: An amplifying circuit includes a first differential amplifier (first differential pair) and a second differential amplifier (second differential pair) having an input capacitance smaller than the first differential amplifier. The amplifying circuit switches between the first differential amplifier (first differential pair) and the second differential amplifier (second differential pair) in response to an amplification mode setting signal to perform amplification processing of an input signal.
    Type: Grant
    Filed: September 15, 2015
    Date of Patent: May 30, 2017
    Assignee: LAPIS SEMICONDUCTOR CO., LTD.
    Inventors: Hiroyoshi Ichikura, Koji Higuchi
  • Patent number: 8788898
    Abstract: An apparatus is provided that comprises a test circuit; a first receiver unit arranged to receive test commands and to provide the test commands to the test circuit; a power supply unit arranged to supply power to the test circuit and to the first receiver unit; a second receiver unit arranged to receive power commands. The second receiver is arranged to control the operation of the power supply unit in response to the power commands received by the second receiver unit.
    Type: Grant
    Filed: June 3, 2011
    Date of Patent: July 22, 2014
    Assignee: STMicroelectronics (Research & Development) Limited
    Inventor: Edward Kent
  • Patent number: 8654867
    Abstract: A method for generating an amplified radio frequency (RF) signal is provided. In-phase (I) and quadrature (Q) signals are received and interleaved so as to generate a time-interleaved signal. Delayed time-interleaved signals are then generated from the time interleaved signal, and each of the delayed time-interleaved signals is amplified so as to generate a plurality of amplified signals. The amplified signals are then combined with a transformer, where the delayed time-interleaved signals are arranged to generate a filter response with the transformer.
    Type: Grant
    Filed: December 7, 2011
    Date of Patent: February 18, 2014
    Assignee: Texas Instruments Incorporated
    Inventors: Rahmi Hezar, Lei Ding, Joonhoi Hur, Baher S. Haroun
  • Patent number: 8575975
    Abstract: A system and method for charging heavy capacitive loads may comprise an n-stage stacked charging circuit wherein n is an integer greater than one which may comprise n?1 capacitors and a voltage supply, each sequentially electrically connected to the capacitive load in an order through a respective first through nth switch during a respective first through nth charging time period; the n?1th capacitors each sequentially electrically connected to the capacitive load in reverse order during a first through n?1th discharging time period through the respective n?1th through first switches. The system and method may comprise an n+1th switch electrically connecting the capacitive load to ground during an nth discharging period. The capacitive load may comprise a piezoelectric element, which may comprise an inkjet printer head inkjet actuator.
    Type: Grant
    Filed: September 30, 2009
    Date of Patent: November 5, 2013
    Assignee: Cirrus Logic, Inc.
    Inventors: Anindya Bhattacharya, John Melanson
  • Patent number: 8541733
    Abstract: The invention provides a laser light detection circuit that prevents a peak output occurring when the circuit switches between the operation stop mode and the operation mode so as to prevent the breakdown or malfunction of the next-connected circuit. A laser light detection circuit has a differential amplifier that amplifies and outputs a signal corresponding to the intensity of laser light, a drive transistor having a base to which the output of the differential amplifier is applied, a second constant-current source connected to the emitter of the drive transistor, an output transistor having a base connected to the emitter of the drive transistor, a bypass transistor connected between the emitter of the drive transistor and the ground, and a control circuit. The control circuit forms a bypass current route from the second constant-current source to the ground through the bypass transistor by turning on the bypass transistor when the circuit switches from the operation stop mode to the operation mode.
    Type: Grant
    Filed: April 14, 2011
    Date of Patent: September 24, 2013
    Assignee: ON Semiconductor Trading, Ltd.
    Inventors: Rui Kurihara, Takahiro Kawashima
  • Patent number: 8400221
    Abstract: An apparatus and method for biasing each amplifier of an amplification stage provides that the voltage across each current sensing element of each amplifier of the amplification stage is measured. For each pair of voltage measurements taken, a sum and difference is calculated, where the sum is processed to determine minima peaks and the difference is averaged. A portion of the sum term and the average of the difference term are summed to yield the individual bias current conducted by a first amplifier of the amplification stage. The difference between a portion of the sum term and the average of the difference term is calculated to yield the individual bias current conducted by the second amplifier of the amplification stage. The bias current conducted by the first and second amplifiers may then be individually modified manually, or conversely, may be modified automatically based upon the bias current measurements taken.
    Type: Grant
    Filed: February 16, 2011
    Date of Patent: March 19, 2013
    Assignee: Fender Musical Instruments Corporation
    Inventor: Charles C. Adams
  • Patent number: 8362649
    Abstract: Embodiments for at least one method and apparatus of a multi-use voltage regulator providing a supply voltage to a power amplifier and at least one other device are disclosed. One method includes generating a plurality of regulated voltage supplies from an unregulated voltage. An output signal power level of the power amplifier is determined. A one of the regulated plurality of voltage supplies and the unregulated voltage supply is selected as a power amplifier voltage supply for the power amplifier based at least in part on the output signal power level of the power amplifier. If the selected power amplifier voltage supply is one of the plurality of regulated voltage supplies, then the selected one of the plurality of regulated voltage supplies is simultaneously provided to the power amplifier and the at least one other device.
    Type: Grant
    Filed: June 18, 2010
    Date of Patent: January 29, 2013
    Assignee: R2 Semiconductor, Inc.
    Inventors: David Fisher, Ravi Ramachandran
  • Patent number: 8189816
    Abstract: A computer controlled amplifier and speaker system includes a power conservation feature allowing ready adaptation to a variety of consumer vehicles, audio systems, and individual consumer purposes. The computer controlled amplifier and speaker system includes an audio-signal detection and power on/off feature and accepts multiple audio inputs and enables multiple audio outputs while also allowing ready adaptation to a variety of power sources. A plurality of power supply functions are readily adapted to supply power to the amplifier and speaker system enhancing user convenience. The disclosed system may be readily adaptable to a portable kit allowing achievement of similar power conservation goals in diverse settings.
    Type: Grant
    Filed: June 5, 2008
    Date of Patent: May 29, 2012
    Assignee: Wolo Mfg. Corp.
    Inventor: Stanley Solow
  • Patent number: 8143949
    Abstract: Several push-pull linear hybrid class H amplifiers are disclosed. A split power rail provides a positive supply rail and a negative supply rail in response to a power supply control voltage. A push-pull amplifier stage is powered by the positive and negative supply rails. The amplifier stage receives an input signal and provides a corresponding amplified output signal. A power supply control circuit provides the power supply control voltage in response to the smaller of the positive and negative supply rails, and the input signal.
    Type: Grant
    Filed: December 24, 2009
    Date of Patent: March 27, 2012
    Assignee: Audera Acoustics Inc.
    Inventors: John B. French, Andrew J. Mason
  • Patent number: 7944302
    Abstract: An apparatus and method for biasing each amplifier of an amplification stage provides that the voltage across each current sensing element of each amplifier of the amplification stage is measured. For each pair of voltage measurements taken, a sum and difference is calculated, where the sum is processed to determine minima peaks and the difference is averaged. A portion of the sum term and the average of the difference term are summed to yield the individual bias current conducted by a first amplifier of the amplification stage. The difference between a portion of the sum term and the average of the difference term is calculated to yield the individual bias current conducted by the second amplifier of the amplification stage. The bias current conducted by the first and second amplifiers may then be individually modified manually, or conversely, may be modified automatically based upon the bias current measurements taken.
    Type: Grant
    Filed: August 24, 2009
    Date of Patent: May 17, 2011
    Assignee: Fender Musical Instruments Corporation
    Inventor: Charles C. Adams
  • Patent number: 7907664
    Abstract: Systems and method to compress digital video based on human factors expressed as a desirability score are provided. A particular method includes passing a digital input signal through a pulse-width modulator and passing an output of the pulse-width modulator through a power switching device. An output of the power switching device has a plurality of pulses. The method includes receiving the output of the power switching device at a first input of a comparator and receiving a reference voltage at a second input of the comparator. The method includes determining a net signal based on an output of the comparator and determining a timing error signal based on the net signal and the digital input signal. The method also includes adjusting the digital input signal to compensate for harmonic distortion based at least in part on the timing error signal.
    Type: Grant
    Filed: December 7, 2009
    Date of Patent: March 15, 2011
    Assignee: Sigmatel, Inc.
    Inventors: Zukui Song, Michael Determan
  • Publication number: 20110043278
    Abstract: An apparatus and method for biasing each amplifier of an amplification stage provides that the voltage across each current sensing element of each amplifier of the amplification stage is measured. For each pair of voltage measurements taken, a sum and difference is calculated, where the sum is processed to determine minima peaks and the difference is averaged. A portion of the sum term and the average of the difference term are summed to yield the individual bias current conducted by a first amplifier of the amplification stage. The difference between a portion of the sum term and the average of the difference term is calculated to yield the individual bias current conducted by the second amplifier of the amplification stage. The bias current conducted by the first and second amplifiers may then be individually modified manually, or conversely, may be modified automatically based upon the bias current measurements taken.
    Type: Application
    Filed: August 24, 2009
    Publication date: February 24, 2011
    Applicant: FENDER MUSICAL INSTRUMENTS CORPORATION
    Inventor: Charles C. Adams
  • Publication number: 20100171552
    Abstract: Several push-pull linear hybrid class H amplifiers are disclosed. A split power rail provides a positive supply rail and a negative supply rail in response to a power supply control voltage. A push-pull amplifier stage is powered by the positive and negative supply rails. The amplifier stage receives an input signal and provides a corresponding amplified output signal. A power supply control circuit provides the power supply control voltage in response to the smaller of the positive and negative supply rails, and the input signal.
    Type: Application
    Filed: December 24, 2009
    Publication date: July 8, 2010
    Inventors: John B. French, Andrew J. Mason
  • Patent number: 7571415
    Abstract: A layout of a power device is provided. The layout includes a substrate, a unit array, a plurality of first, second, third and fourth signal paths, and a first, second, third and fourth port. The unit array with a plurality of rows is disposed on the substrate. Each row of the unit array includes a plurality of units. The first and second signal paths on the substrate are disposed on a first side and a second side of corresponding odd-numbered rows of the unit array. The third and the fourth signal paths on the substrate are disposed above a corresponding row of the unit array. The first to fourth ports on the substrate are electrically connected to the first to fourth signal paths respectively.
    Type: Grant
    Filed: January 23, 2007
    Date of Patent: August 4, 2009
    Assignee: United Microelectronics Corp.
    Inventors: Houshang Aghahassan, Albert Kuo Huei Yen, Chung-Che Reed, Tsung-Chien Wu
  • Patent number: 6970152
    Abstract: A column driver for a graphics display has reduced power consumption by sharing power between upper and lower column amplifiers. The upper column amplifier operates over an upper supply range, while the lower column amplifier operates over a lower supply range. The upper and lower amplifiers have the substantially the same quiescent operating current such that the total operating current for the column drivers in the graphics display is reduced by a factor of two. Each column amplifier can be driven over half of the power-supply range such that lower voltage amplifiers may be employed for the column driver amplifiers.
    Type: Grant
    Filed: November 5, 2002
    Date of Patent: November 29, 2005
    Assignee: National Semiconductor Corporation
    Inventors: Marshall J. Bell, Christopher A. Ludden, Richard Alexander Erhart
  • Patent number: 6759901
    Abstract: A dynamic sensor regulator that provides a mechanism for introducing desirable tonal artifacts in component-based guitar amplifier systems by inducing voltage fluctuations into the power supply of a preamplifier. The dynamic sensor regulator comprises a regulator circuit, connected to an amplifier that is connected to a converter circuit that is connected to a variable control circuit. The amplifier includes a floating bias circuit that dynamically adjusts the bias state of an output driving amplifier in response to signal fluctuations of the regulator output signal. A transformer is connected to the amplifier output and once the transformer's saturation point has been reached, the saturation of the transformer increases proportionally with the amplifier's input signal while the regulated output signal remains constant, emulating amplifier overload and saturation.
    Type: Grant
    Filed: November 21, 2002
    Date of Patent: July 6, 2004
    Assignee: VHT Amplification, Inc.
    Inventor: Steven M Fryette
  • Patent number: 6703080
    Abstract: A radio frequency (RF) generator apparatus for a plasma processing system that is resistant to nonlinear load mismatch conditions is provided. The apparatus includes an RF oscillator configured to generate an RF signal, an RF amplifier responsive to the RF signal to produce a VHF RF signal having sufficient power to drive a plasma chamber load, and a VHF-band circulator coupled to the amplifier and configured to isolate nonlinearities of the plasma chamber load from the amplifier.
    Type: Grant
    Filed: May 20, 2002
    Date of Patent: March 9, 2004
    Assignee: ENI Technology, Inc.
    Inventors: Leonid E. Reyzelman, John E. Sortor
  • Patent number: 6683496
    Abstract: The variable power supply to an amplifier in an electrical circuit is dynamically controlled through the use of a lookup table responsive to one or more operating conditions of the electrical circuit. The lookup table is indexed by one or more of the operating conditions and the amount of amplification to be applied to an input signal to the amplifier is determined. One embodiment of the invention comprises a television transmitter circuit including a power amplifier circuit capable of amplifying a variable frequency COFDM or 8VSB input signal where the amount of amplification applied to the input signal is dynamically controlled through the use of a lookup table as a function of the frequency of the input signal.
    Type: Grant
    Filed: August 20, 2001
    Date of Patent: January 27, 2004
    Assignee: Harris Corporation
    Inventors: Peter John Poggi, Tim Dittmer, George Cabrera
  • Patent number: 5909145
    Abstract: Sag of a power signal delivered to of an amplifier is controlled. The maximum amount of sag is limited to limit crossover distortion. A measuring circuit monitors an observed signal to generate a measured signal. A sag control circuit receives the measured signal and one or more input control signals, and in response generates a sag control signal. A regulator circuit receives the sag control signal and a raw power supply signal and in response generates a regulated DC power supply signal for the amplifier. The regulator circuit decreases the maximum power available to the amplifier as the sag control signal magnitude increases, so as to increase distortion and compression in the output signal (e.g., and achieve a "warm", "airy" or "forgiving" sound quality resembling or improving the sound of a vacuum tube amplifier).
    Type: Grant
    Filed: December 3, 1996
    Date of Patent: June 1, 1999
    Assignee: Maven Peal Instruments, Inc.
    Inventor: David G. Zimmerman
  • Patent number: 5793252
    Abstract: An electronic amplifying apparatus for sound reproduction and musical instrument amplification including at least two pairs of power output devices which are independently switchable between triode and pentode operation. The amplifier further contains a switch apparatus to select the amount of negative feedback within the amplifier.
    Type: Grant
    Filed: December 9, 1996
    Date of Patent: August 11, 1998
    Assignee: Mesa Boogie, Limited
    Inventor: Randall C. Smith
  • Patent number: 5635872
    Abstract: A regulated power supply control system with adjustable operating point and adjustable dynamic behavior for use with electronic power supply circuits, such as musical instrument amplifiers. The control system includes a measurement circuit (20) that generates a measured signal (22) based on an observed signal (18) in an amplifier (10); a sag control circuit (24) that generates a sag signal (32) based on the measured signal (22); a referenced circuit (34) that generates a static reference signal (38); and a regulator (44) that uses the static reference signal (38) and sag signal (32) to generate a regulated power supply output (14) that is used by the amplifier (10). The sag control circuit (24) permits adjustment of the sag signal 32 by a user-operated sag magnitude control (26), sag rate control (28), and sag recovery rate control (30).
    Type: Grant
    Filed: November 16, 1995
    Date of Patent: June 3, 1997
    Assignee: Maven Peal Instruments, Inc.
    Inventor: David G. Zimmerman
  • Patent number: 5559469
    Abstract: A power output amplifier for use with electric guitar wherein the individual pairs of power tubes are of two or more differing types which may be selected by the user to operate alternately or simultaneously.
    Type: Grant
    Filed: March 14, 1994
    Date of Patent: September 24, 1996
    Inventor: Randall C. Smith
  • Patent number: 5550509
    Abstract: An output power selection apparatus reduces the R.M.S. power output of a tube type amplifier without the use of solid state devices or ganged high or low power potentiometers.
    Type: Grant
    Filed: January 9, 1995
    Date of Patent: August 27, 1996
    Inventor: Salvatore J. Trentino
  • Patent number: 5546046
    Abstract: A tonal altering feature for a tube type guitar audio amplifier provides apparatus enabling the selection of the method of output tube bias.
    Type: Grant
    Filed: January 9, 1995
    Date of Patent: August 13, 1996
    Inventor: Salvatore J. Trentino
  • Patent number: 5170495
    Abstract: In a QAM microwave radio communications system an IF (intermediate frequency) input signal is amplified and predistorted, and the amplified IF signal is mixed with a local oscillator signal to produce an RF (radio frequency) signal which is amplified in a power amplifier for transmission, the predistortion compensating for non-linear gain of the power amplifier. Clipping in the power amplifier is controlled by down-converting part of the RF signal to produce an IF output signal, monitoring amplitude distortion of the RF signal by comparing the IF output signal with the IF input signal, and controlling the IF amplifier gain in dependence upon the monitored amplitude distortion.
    Type: Grant
    Filed: October 31, 1990
    Date of Patent: December 8, 1992
    Assignee: Northern Telecom Limited
    Inventors: John D. McNicol, Stephen G. Harman
  • Patent number: 5022305
    Abstract: The distortion pedal for electric guitar and other electronic musical instruments employs vacuum tube circuitry operated by low voltage "battery eliminator" DC power supply. A pull-up resistor biasing circuit on the vacuum tube grid improves input and output impedance and circuit headroom while providing good control over the harmonic content and sustain.
    Type: Grant
    Filed: April 20, 1989
    Date of Patent: June 11, 1991
    Inventor: Brent K. Butler
  • Patent number: 4719431
    Abstract: A push-pull power amplifier includes a pair of input terminals, a pair of output terminals, a pair of matched output tubes having cathode, plate, and grid terminals, and a pair of output power supplies, all of which are connected to form a bridge circuit. A floating bias supply is coupled between the grid and plate of both output tubes. A first feedback resistor couples the floating bias supply to the cathode of the first output tube. A second feedback resistor couples the floating bias supply to the cathode of the second output tube. The floating bias supply and feedback resistors provide degenerative feedback without affecting power gain.
    Type: Grant
    Filed: April 21, 1986
    Date of Patent: January 12, 1988
    Inventor: Ralph R. Karsten
  • Patent number: 4636740
    Abstract: A biasing and control circuit for varying the output power delivered by the push-pull output stage of a power amplifier is disclosed. The biasing and control circuit incorporates both fixed and cathode biasing to allow output power to be varied without introducing distortion. A negative fixed biasing voltage is applied to the control grids of the vacuum tubes comprising the push-pull output stage, while the cathodes of such tubes are varied between ground and selected voltage levels above ground. To vary the voltage levels, the cathodes of the tubes are joined together by a common connection and coupled to ground through a variable impedance which when varied changes the conductivity of the output tubes, and thereby, the output power delivered by the amplier.
    Type: Grant
    Filed: July 7, 1986
    Date of Patent: January 13, 1987
    Inventor: Dennis L. Kager
  • Patent number: 4593251
    Abstract: An electronic amplifying apparatus intended for sound reproduction and for music instrument amplification wherein two parallel amplifiers, working simultaneously, each in a different class of operation, are fed from a single driver or signal source and whose outputs are combined. In the preferred embodiment at least two pairs of push-pull vacuum tubes are required and they are arranged so that one pair operates Triode Class A while the other pair (or pairs) operates Pentode Class AB (or Class B). The circuit can then be optimized so that the desirable sonic characteristics of Class A Triode operation are imparted into the Class AB (or Class B) Pentodes which actually produce all or nearly all of the power. The output power waveform has the high power and efficiency typical of Class AB (or Class B) Pentode operation but without the detrimental sonic side effects, namely, there is the complete absence of crossover or "notch" distortion, and there is a "soft" gradual onset of clip.
    Type: Grant
    Filed: May 7, 1985
    Date of Patent: June 3, 1986
    Inventor: Randall C. Smith
  • Patent number: 4532476
    Abstract: An electronic amplifying apparatus intended for sound reproduction and for music instrument amplification wherein two parallel amplifiers, working simultaneously, each in a different class of operation, are fed from a single driver or signal source and whose outputs are combined. In the preferred embodiment at least two pairs of push-pull vacuum tubes are required and they are arranged so that one pair operates Triode Class A while the other pair (or pairs) operates Pentode Class AB (or Class B). The circuit can then be optimized so that the desirable sonic characteristics of Class A Triode operation are imparted into the Class AB (or Class B) Pentodes which actually produce all or nearly all of the power. The output power waveform has the high power and efficiency typical of Class AB (or Class B) Pentode operation but without the detrimental sonic side effects, namely, there is the complete absence of crossover or "notch" distortion, and there is a "soft" gradual onset of clip.
    Type: Grant
    Filed: April 29, 1983
    Date of Patent: July 30, 1985
    Inventor: Randall C. Smith
  • Patent number: 4449103
    Abstract: A method for amplifying electric signals, an amplifier circuit and application of this amplifier circuit as the modulator stage of a subsequent amplifier, employing a variable anode voltage for the purpose of improving the efficiency of amplifiers and particularly of high-power modulation amplifiers which are used, for example, in broadcast transmitters for the amplitude modulation of the radio-frequency output stage. From the modulation signal to be amplified, a control signal is derived in a control stage, this control signal being associated with the amplitude of the envelope of this modulation signal and being used for controlling the output voltage of a modulator/rectifier. The control signal is caused to follow the modulation signal within a presettable response time.
    Type: Grant
    Filed: December 4, 1981
    Date of Patent: May 15, 1984
    Assignee: BBC Brown, Boveri & Company, Limited
    Inventor: Bohumil Kyrian
  • Patent number: 4353036
    Abstract: A complementary symmetry amplifier having variable gain control is used in an automatic gain control (AGC) system. The amplifier includes first and second field effect transistors of opposite conductivity type. Variable gain control is achieved by applying first and second differential control signals to respective gate electrodes of said first and second field effect transistors.
    Type: Grant
    Filed: August 29, 1980
    Date of Patent: October 5, 1982
    Assignee: RCA Corporation
    Inventor: Merle V. Hoover
  • Patent number: 3995226
    Abstract: An audio amplifier in which an output stage is coupled by a driver stage to an input stage which includes two antiphased sources of alternating current. The output stage includes two pentode vacuum tubes each having a cathode, a plate and a screen grid located between the cathode and the plate. Each tube has a control grid connected between the cathode and the screen grid and a suppressor grid connected between the screen grid and the plate, with the control grid and the suppressor grid being shunted to their respective cathodes. The driver stage includes a pair of transistors connected in a push-pull configuration with their emitters connected to the screen grids of said tubes to supply a relatively high value of alternating current to the screen grids which function as control grids for their respective tubes.
    Type: Grant
    Filed: June 10, 1976
    Date of Patent: November 30, 1976
    Inventor: David W. Berning