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7432766 Front end for an instrumentation amplifier  
An amplifier system includes an instrumentation amplifier arrangement being designed to amplify the difference between two voltage inputs with a defined gain, and to produce a single-ended output...
7423491 Semiconductor amplifier  
A first power source 11 for supplying a bias voltage to a gate electrode G of a field effect transistor 13 , which amplifies high-frequency signals, and a second power source 15 for supplying...
7391267 Output circuit  
A patterning area of an output circuit is reduced while securing strong enough ESD tolerance. In the output circuit of this invention, an output of a first amplifier and an output of a second...
7375589 Power amplifier system provided with improved protection function  
The present invention provides a power amplifier system that includes a power terminal, a ground terminal, an output terminal, a ripple terminal, a control terminal, a power amplifier circuit...
7362871 Audio amplifier circuit and audio IC having the same  
In the present invention, in parallel with a resistor which determines an amplification rate being fed back from an output to an input of an output stage OP amp in an audio amplifier circuit,...
7362181 Procedure for operating a high frequency amplifier  
A procedure for operation of a high frequency amplifier having a power transistor—amplifier stage designed as a source or emitter circuit for amplifying a gate or base side high frequency signal...
7362180 Protection circuit of digital amplifier  
A protection circuit of a digital amplifier includes a DC voltage detection circuit for detecting a DC voltage occurring in a loudspeaker output terminal; a control circuit for performing...
7355476 Input stage for an amplifier  
In one embodiment, the present invention includes an amplifier having an input to receive a radio frequency (RF) signal from an output node of a source. An input stage coupled to the amplifier...
7352240 Method and apparatus for protecting devices in an RF power amplifier  
A method and apparatus are provided for use with a power amplifier for protecting active devices on the power amplifier. A peak detector is used by control circuitry to detect the presence of a...
7348854 Automatic biasing and protection circuit for field effect transistor (FET) devices  
A transistor biasing circuit is shown that utilizes a negative feedback loop control circuit to set the gate bias voltage in the output transistors of a power amplifier. This control circuit has a...
7339424 Apparatus and method for controlling temperature of electronic apparatus  
In an embodiment of this invention, if a state, in which duty ratio of a PWM signal is kept equal to or greater than a predetermined value, has been maintained for a first time period, the duty...
7332969 Output offset protection for power amplifier  
A output offset protection circuit provides protection of the load and the power amplifier through monitoring the temperature of the power transistor in the operational amplifier to detect fault...
7327187 Method, circuit and power amplifier for detecting a fault, and method of protecting a circuit in a power amplifier from a fault occurrence  
In a method of detecting a fault in a class D amplifier, an amplifier output signal is generated based on inverting a pulse width modulation signal corresponding to received audio data. The...
7307478 Adjustable power amplifier and applications thereof  
An adjustable power amplifier includes an input capacitor, an input transistor, an inductor, an output capacitor, and a gain module. The input capacitor includes a first plate and a second plate,...
7301402 Soft saturation detection for power amplifiers  
A soft saturation detection circuit for a radio frequency (“RF”) power amplifier is configured to detect the onset of soft saturation in an unambiguous and accurate manner. The circuit compares...
7286010 Systems and methods for over-current protection  
Systems and methods for over-current protection in all-digital amplifiers using low-cost current sensing mechanisms. An over-current hard clipping unit receives a digital audio signal, clips the...
7276974 Method and apparatus for protecting RF power amplifiers  
Method and apparatus are provided for protecting radio frequency (RF) power amplifiers. A circuit ( 10 ) is provided for limiting a supply current to a first stage (Q 3 ) of the RF power amplifier...
7276968 Class D amplifier  
A drive signal that matches the bias of a transistor is generated. A differential amplifier calculates the difference between a specified voltage of negative power supply and another input signal....
7268990 Power amplifier protection  
A power amplifier protection circuit that includes protection circuitry to variably shunt an input radio frequency (RF) signal to AC ground, turn off bias to an output transistor of a power...
7262668 Semiconductor amplifier  
A first power source 11 for supplying a bias voltage to a gate electrode G of a field effect transistor 13 , which amplifies high-frequency signals, and a second power source 15 for supplying...
7262667 Radio frequency power amplifier  
A radio frequency (RF) power amplification circuit including a power amplifier is provided for preventing breakdown of the power amplifier. The power amplifier includes an input for receiving RF...
7256652 Differential input receiver having over-voltage protection  
A differential receiver circuit. In one embodiment, the circuit includes first and second input transistors, each having a first terminal coupled to a bias node (a first and second bias node,...
7253687 Clamping circuit for operational amplifiers  
A differential input operational amplifier has a voltage clamp differential transistor pair coupled to an input differential transistor pair of the operational amplifier. The voltage clamp...
7221227 Methods and apparatus for reducing output current oscillations of a driver provided with circuitry that senses and responds to excessive current draws of an output stage of the driver  
In one embodiment, a method is provided for reducing output current oscillations of a driver provided with i) a current sensing circuit that senses excessive current draws of an output stage of the...
7205843 Protection circuit for power amplifier  
A directional coupler is provided on the output side of a power amplifier. An increase in reflected wave power from a load is detected through the directional coupler by an electric power detector...
7205840 Wideband CMOS gain stage  
A CMOS gain stage includes biasing circuitry configured to insure saturation of a subsequent stage without a source follower circuit. The CMOS gain stage is optionally powered by a supply voltage...
7205834 Power amplifier  
In a power amplifier driven by a pulse width modulation (PWM) signal, a first pair of drive pulses opposite in level to each other is formed from a first pulse width modulation signal whose...
7202749 AC coupling technique for improved noise performance and simple biasing  
A low noise amplifier (LNA), which utilizes an AC coupling technique that can internally bias diodes in such a way as to provide effective low noise amplification, is provided. The low noise...
7196586 Oscillator amplifier circuit operable to provide symmetric current limiting and method of same  
An amplifier circuit operable to provide symmetric current limiting. The amplifier circuit includes a common source amplifier for sourcing a current and receiving an voltage input, a current...
7196585 Fast-response current limiting  
An amplifier ( 10″ ) has a first amplifier stage ( 14 ) for producing a control current (I X ) in response to an input voltage. A second amplifier stage ( 16 ) has first ( 46 ) and second ( 38 )...
7193474 Current limit circuit for power amplifiers  
According to one embodiment of the invention, a circuit arrangement includes a regulator circuit. The circuit arrangement further includes a current limit circuit coupled to the regulator circuit....
7190934 Reflected power suppression circuit  
An amplifier 3 amplifies a transmission signal, and outputs the amplified signal to an antenna. A directional coupler 6 causes a portion of power passing through a first path connecting the...
7167055 Voltage level detector for power amplifier protection control  
A voltage level detector ( 8 ) which activates itself by monitoring the voltage level (V STB ) at a standby pin ( 5 ) during power-up of an audio power amplifier ( 10 ), and can detect fault...
7164320 Current threshold circuit  
A current threshold circuit includes a series impedance, a reference voltage source, and a comparison module. The series impedance couples an output of a current source to a load, wherein impedance...
7161990 Predistortion amplifier  
Unlike a prior art digital predistortion compensation device for determining a compensation coefficient based on absolute value information about a baseband complex input signal, the present...
7158633 Method and apparatus for monitoring subscriber loop interface circuitry power dissipation  
Subscriber line interface circuitry includes an integrated circuit having sense inputs for a sensed tip signal and a sensed ring signal of a subscriber loop. The integrated circuit generates a...
7157968 Method and apparatus for protecting a switching amplifier from excess current  
A class D switching amplifier has a pulse width modulator that drives a speaker. The amplifier includes an over-current protection circuit, which includes current-monitoring MOSFETs that are each...
7145397 Output overvoltage protection circuit for power amplifier  
Disclosed is an output overvoltage protection circuit for a power amplifier having a plurality of stages, which comprises a monitor circuit for monitoring an output overvoltage of an output...
7145396 Method and apparatus for protecting devices in an RF power amplifier  
A method and apparatus are provided for use with a power amplifier for protecting active devices on the power amplifier. A peak detector is used by control circuitry to detect the presence of a...
7136774 Sense amplifier thermal correction scheme  
A system and method of adjusting a sense amplifier includes providing an amplification control parameter to the sense amplifier. A temperature of the sense amplifier is monitored and the...
7132886 Detecting load current in multi-reference amplifiers  
A method and apparatus are disclosed for inferring amplifier load current from an internal control voltage governing a reference voltage in a multi-reference amplifier. Multi-reference amplifiers...
7113042 Low noise op amp  
The present invention relates amplifiers using metal oxide semiconductor based integrated circuits. The present invention is particularly but not exclusively related to audio application mixed...
7109801 Low gate oxide stress power amplifier  
A power amplifier includes an input transistor, an output transistor, and circuitry. The input transistor includes an input, a first node, and a second node, wherein the second node of the input...
7102445 Power amplifier module  
An amplifier 2 c amplifies a transmit signal and outputs the amplified transmit signal to an antenna 10 . A drive current for driving the amplifier 2 c is inputted to a drive current input...
7075373 Overcurrent protection circuit with fast current limiting control  
An overcurrent protection circuit for a power transistor includes a transconductance amplifier and a bias current circuit. The transconductance amplifier receives a first signal indicative of the...
7043033 Mode control for audio amplifier coupling  
An audio amplifier system includes two amplifiers that are configured to drive loads through either DC or AC coupling. A third amplifier provides an AC ground return when the system is configured...
7034610 Apparatus, system, and method for amplifying a signal, and applications thereof  
An upstream amplifier is integrated on a substrate with a digital-to-analog converter (DAC) to form an integrated circuit. In an embodiment, a low-pass filter is also integrated on the substrate....
7030700 Voltage level detector for power amplifier protection control  
A voltage level detector ( 8 ) activates itself through monitoring the voltage level (VSTB) at a standby pin ( 5 ) during power-up of an audio power amplifier ( 10 ), and can detect fault...
7005924 Current limiting circuit with rapid response feedback loop  
The current limiting circuit of the present invention includes a transconductance amplifier having two outputs and forming a conventional feedback loop. A first output connects to an output...
6998920 Monolithically fabricated HBT amplification stage with current limiting FET  
A monolithically integrated amplifier comprising at least one heterojunction bipolar transistor and at least one field effect transistor is disclosed wherein the field effect transistor provides...