Abstract: An oscillator circuit comprises a push-push oscillator and a differential output, comprising a first and a second output circuit. The push-push oscillator has a first and a second branch. Each of the first and second branch comprises an own voltage divider branch of a common bridge circuit. Each of the first and second voltage divider branches comprises an own pair of micro-strip lines connected in series. Each of the first and second voltage divider branches has an own tap. Both taps are connected to each other by at least one of a first capacity and a micro-strip line. The differential output comprises a first and a second output terminal. The first output terminal is connected via the first output circuit to a first node. The second output terminal is connected via the second output circuit to a second node. Each of the first and second nodes of the push-push oscillator is a common node of both of the first and the second branches.
Abstract: The present disclosure relates to coupled circuits and methods of coupling circuits having a power supply wherein a plurality of transistors are inductively coupled directly to the power supply for providing a single DC supply voltage directly to each of the plurality of transistors, and wherein a plurality of transformers have primary and secondary windings, the primary and secondary windings providing, at least in part, inductive loads for inductively coupling the plurality of transistors to the power supply, the plurality of transformers also providing an AC signal path for coupling neighboring ones of the plurality of transistors together.
August 2, 2006
Date of Patent:
September 20, 2011
The Regents of the University of California
Mau-Chung Frank Chang, Daquan Huang, Tim Richard LaRocca
Abstract: Presently many audio chips suffer from pop issues, which is especially serious for single ended audio drivers. An audio pop is a disturbance in the output caused by a sudden transition of chip power, particularly when a chip is powered on or powered off. Furthermore, compensation networks included in the amplifiers on audio chips for stability offer a significant path for transmitting power disturbances to the output. Hence, circuitry is developed to suppress pops in the output stages of an amplifier.
June 19, 2009
December 23, 2010
CONEXANT SYSTEMS, INC.
Xin Fan, Christian Larsen, Lorenzo Crespi
Abstract: An audio amplifier including a series connected vacuum tube output stage for driving an audio loudspeaker. The preferred amplifier uses the output signal as a floating reference for an intermediate stage to prevent output stage degeneration for producing balanced push-pull drive signals, thereby eliminating the need for an output transformer or AC coupling.
Abstract: An amplifier comprising a first and a second amplifier element, whose outputs are connected to a load, a difference circuit which comprises a comparator, in which the output signal of the first amplifier element is compated with the input signal thereof to produce a correction signal which is applied to second amplifier element, and a second substantially identical difference circuit which comprises a comparator in which the output signal of the second amplifier element is compared with the input signal thereof to produce a correction signal which is applied to the first amplifier element; a desired signal to be amplified being applied to both amplifier elements. The two amplifier elements, which may be preceded by preamplifiers, take the form of power amplifiers. Because the distortion signals appear at the load as "common mode" signals, the overall distortion becomes substantially zero in the case of equal attentuation in the two difference circuits.
June 2, 1980
Date of Patent:
March 23, 1982
U.S. Philips Corporation
Nico V. Franssen, Gerardus A. Van Maanen, Henricus G. J. M. Kockelmans
Abstract: A broad-band radio-frequency amplifier is characterized by a gain which may be adjusted over a relatively large range, and which remains stable over the range of gain adjustments. The amplifier includes first and second transistor pairs each arranged in a cascode connection; a feedback capacitor connected across the output and input of each cascode pair; and inductance serially included at selected circuit points. Also disclosed is a hybrid circuit for efficiently implementing the amplifier.
Abstract: In a wide-band electronic AC amplifier, the first stage is direct coupled to a split load phase inverter which is RC coupled to a push-pull power output stage and the output is obtained through transformer coupling with a portion being returned to the cathode of the input stage as negative feedback. Instability (e.g., generation of high frequency "parasitics") is prevented by reduction of the effective impedance of the phase splitter, as seen by the control grids of the output tubes, by greatly lowering the resistance thereof. Since the triode is DC coupled to the pentode, the values of the load resistor and the screen dropping resistor in the pentode section must be reduced in order to increase the high frequency response and keep the current flow in the triode section within the maximum safe limits of the tube design.