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| Number | Title | Issue Date |
| 7425869 | Distributed circular geometry power amplifier architecture The present invention discloses a distributed power amplifier topology and device that efficiently and economically enhances the power output of an RF signal to be amplified. The power amplifier comprises a plurality of push-pull amplifiers interconnected in a novel... | 09/16/2008 |
| 7355475 | Output circuit of vacuum-tube amplifier An output circuit of a vacuum-tube amplifier is disclosed. An output circuit of a conventional vacuum-tube amplifier has shortcomings that a front end amplification unit uses a coupling condenser or a transformer to output an AC signal to an output node, a bias volt... | 04/08/2008 |
| 7321752 | Linear amplification arrangement with non-linear amplifier element for a mobile radio device A system and method to optimize the efficiency of an amplifier device is provided by the including a non-linear amplifier in a mobile radio device. A phase displaced signal in relation to the input signal is respectively produced in the amplifier device with a non-l... | 01/22/2008 |
| 7202733 | Transconductance amplifiers with compensation An amplifier circuit comprises a first operational transconductance amplifier (OTA) has an input that communicates with the output of the first amplifier. A third amplifier has an input that communicates with the input of the first amplifier and an output. A fourth ... | 04/10/2007 |
| 7199656 | Amplifiers with compensation An amplifier circuit includes a first amplifier module that includes an input and an output and that has first gain, a first bandwidth and a first output impedance. A second amplifier module includes an input that communicates with the input of the first amplifier m... | 04/03/2007 |
| 7161420 | Amplifiers with compensation An amplifier circuit comprises a first operational transconductance (OTA) having an input and an output and a second OTA having an input that communicates with an output of the first OTA. A third OTA has an input that communicates with an input of the first OTA. A f... | 01/09/2007 |
| 7145392 | Methods and apparatus for variable harmonic distortion Methods and apparatus for producing first and second drive signals from an input signal such that each drive signal is about 180 degrees out of phase with respect to the other; variably altering at least one of the first and second drive signals such that their resp... | 12/05/2006 |
| 7142017 | High-voltage-tolerant feedback coupled I/O buffer An input/output buffer comprises an input/output pad operable to receive an input signal and transmit an output signal, an output driver coupled to the input/output pad, an input path comprising an input transistor coupled to the input/output pad operable to pass an... | 11/28/2006 |
| 7092533 | BTL amplifier apparatus A BTL amplifying apparatus has two power amplifiers in an BTL configuration for amplifying a speaker. It includes detection means for detecting a differential voltage between outputs from the two power amplifiers while an input signal to be supplied to the power amp... | 08/15/2006 |
| 7075371 | Distributed circular geometry power amplifier architecture The present invention discloses a distributed power amplifier topology and device that efficiently and economically enhances the power output of an RF signal to be amplified. The power amplifier comprises a plurality of push-pull amplifiers interconnected in a novel... | 07/11/2006 |
| 7068099 | Power amplifier module with distortion compensation The invention relates to a power amplifier module comprising a first amplifier 2 having a first front-end 4 and a first backend amplifier stage 5 and a second amplifier 3 having a second front-end 6 and a second backend amplifier s... | 06/27/2006 |
| 7034616 | Operational amplification circuit, overheat detecting circuit and comparison circuit In a circuit according to the present invention, a multi-collector transistor is provided which includes first to third collectors so that, when a current does not flow from the second collector, a current from the first collector increases but a current from the th... | 04/25/2006 |
| 7015756 | Push-pull buffer/amplifier A differential circuit comprises first, second, third and fourth devices that have first, second, third and fourth control terminals, respectively. The second and fourth devices are arranged in series with the first and third devices, respectively. A first output co... | 03/21/2006 |
| 7002433 | Microwave coupler A high power, TEM mode directional microwave coupler having low loss and expanded bandwidth uses novel thick suspended substrate conductors to provide multi-octave bandwidth performance in a practical package. Each of two center conductors is formed using metal laye... | 02/21/2006 |
| 6975172 | Smart voltage rail reduction audio amplifier An audio amplifier is provided that adjusts the supply voltage rails communicated to a power amplifier circuit according to the circuit's output. The amplifier compares the output voltage from the power amplifier to a predetermined voltage range to determine if the ... | 12/13/2005 |
| 6917245 | Absolute power detector 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 ... | 07/12/2005 |
| 6838940 | High frequency power amplifier circuit A high frequency power amplifier circuit comprises an input circuit receiving an input signal; a first cascode stage connected to the input circuit and a DC voltage source and comprising at least one FET having a source, a drain, and a gate; an second cascode stage ... | 01/04/2005 |
| 6816012 | Distributed circular geometry power amplifier architecture The present invention discloses a distributed power amplifier topology and device that efficiently and economically enhances the power output of an RF signal to be amplified. The power amplifier comprises a plurality of push-pull amplifiers interconnected in a novel... | 11/09/2004 |
| 6792121 | Audio signal amplifier circuit and portable telephone set and portable electronic device using the same audio signal amplifier circuit An audio signal amplifier circuit includes an external output terminal of an IC to which an output line of a power amplifier circuit is connected, a first resistor connected between a certain terminal of the IC other than the external output terminal and a feedback ... | 09/14/2004 |
| 6765438 | Transconductance power amplifier A transconductance power amplifier for amplifying a signal to a capacitive load, including a first N-channel enhancement MOSFET transistor operatively arranged to source current to the capacitive load, wherein the first N-channel MOSFET transistor has a threshold ga... | 07/20/2004 |
| 6731170 | Source drive amplifier of a liquid crystal display A source drive amplifier has a first input circuit controlled by a polarity switching signal for being switched into an NMOS differential amplifying circuit or a bias circuit, and a second input circuit controlled by a polarity switching signal for being switched in... | 05/04/2004 |
| 6714076 | Buffer circuit for op amp output stage An op amp includes a pair of buffer amplifiers interposed between the current switch and the output transistors in an output stage based on the Monticelli architecture. The buffer amps buffer the output transistors' gate capacitances, thereby allowing the output tra... | 03/30/2004 |
| 6630865 | Push-pull amplifiers A push pull amplifier is disclosed having upper and lower output devices operating in a mode in which the devices drive a load alternately. The amplifier includes bias means for providing a bias current to the output devices at all times. The bias means i... | 10/07/2003 |
| 6608905 | Microphone bias current measurement circuit A microphone bias current detection circuit includes: a microphone circuit 18; an amplifier 10 having a first output and a second output, the first output is coupled to the microphone circuit 18 for providing a bias current to the microphone circuit 18, t... | 08/19/2003 |
| 6489839 | Amplifier with output transformer An amplifier for use in, for example, Public Address Systems to send audio signals over long distances, is of the push-pull type and includes a first and a second switch and an output transformer having a primary winding coupled to the switches and a seco... | 12/03/2002 |
| 6473009 | PWM power amplifier A PWM power amplifier having at least one PCM/PWM converter fed by PCM digital input signals and producing PWM digital output signals, and at least one power amplification final stage of the PWM digital output signals. At least one PCM/PWM converterinclud... | 10/29/2002 |
| 6420914 | Charge pump circuit having switching circuits for reducing leakage currents To reduce leakage current from a current source transistor in a charge pump circuit of a PLL circuit, the charge pump circuit is activated according to an up signal or a down signal generated according to whether the phase of a clock output from VCO is fa... | 07/16/2002 |
| 6374043 | Fully-integrated VCM driver with controlled and predictable Class-AB linear operation A circuit (41) to provide drive voltages to a voice coil motor (VCM) (50) of a hard disk drive (10) has identical high and low side drivers (42, 44, 46, and 48) connected to the VCM (50). Each driver has an output FET (52) selectively connecting the VCM (... | 04/16/2002 |
| 6222417 | Amplifier output stage provided with a parasitic-current limiter An output stage for an amplifier AMP includes a first transistor T1 and a second transistor T2 having their main current paths arranged between two power supply terminals VCC and GND, the bias terminal of the first transistor T1 being connected to the out... | 04/24/2001 |
| 6150853 | Integrated unit gain output stage The operation of externally connected output power transistors of a class AB amplifier is controlled without employing any external sensing resistance of the output current by driving an externally connected power transistor through a level shifting buffe... | 11/21/2000 |
| 6072341 | Driver circuit with pull down npn transistor and gain reduction A driver circuit with pull down npn transistor drives an output voltage signal in response to an input voltage signal, without high-speed pnp transistors. A first npn transistor provides current to the output node when the output node is at a level equal ... | 06/06/2000 |
| 6069959 | Active headset An active headset providing for reduction of external noise over a given frequency range by means of a microphone which generates an external noise representative signal processed and fed to a loudspeaker to produce an external noise cancellation signal s... | 05/30/2000 |
| 6011438 | Push-pull wideband semiconductor amplifier A push-pull wideband semiconductor amplifier for use in, for example, a CATV (cable television) system. The amplifier suppresses deterioration of composite second-order (CSO) distortion in output signals. The push-pull wideband amplifier includes: a divid... | 01/04/2000 |
| 5963093 | Class AB output stage wih reduced distortion An output stage of an amplifier circuit includes: a sinking bipolar circuit 23 for sinking current from an external load; a sourcing transistor 14 for sourcing current to the external load, the sourcing transistor 14 coupled in series with the sinking bip... | 10/05/1999 |
| 5874858 | Amplifier system having a constant current regulating unit An amplifier system includes a constant current unit which produces a constant current in response to a source voltage from a source voltage terminal. An emitter follower unit has a base, an emitter and a collector, an input signal being supplied to the b... | 02/23/1999 |
| 5805713 | Solid state circuit for emulating push-pull tube amplifier A solid state emulation of vacuum tube amplifiers and more particularly to the emulation of push-pull output stages. This application focuses on the emulation of grid conduction by the output tubes and their non-linear transconductance.... | 09/08/1998 |
| 5764105 | Push-pull output circuit method A push-pull output circuit includes first and second transistors each having a base coupled to a first conductor coupled to respond to an input signal. An emitter of the first transistor is coupled by a first resistor to a first supply voltage conductor a... | 06/09/1998 |
| 5552741 | High impedance common-emitter amplifier stage A high input impedance common-emitter amplifier stage is disclosed. This amplifier stage utilizes a transistor to buffer the base drive from the input stage of a Darlington circuit. This buffer action increases the input impedance of the common-emitter st... | 09/03/1996 |
| 5396193 | Frequency response-compensated circuit A frequency compensated circuit includes a frequency compensation component and a negative feedback loop for feeding an output signal to the circuit input terminal. The circuit input terminal also receives a compensation signal from the frequency compensa... | 03/07/1995 |
| 5359295 | Power amplifier A power amplifier is provided, wherein the output of a first transistor supplied with an input signal at the base thereof is supplied to the base of a second transistor, a current proportional to a collector current of the second transistor is supplied to... | 10/25/1994 |
