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7180365 |
Class D amplifier and a method of pulse width modulation
A class D amplifier and a method of pulse width modulation are provided. The class D amplifier includes a sigma delta modulator, a reference signal generator, a pulse width modulator and an...
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7170339 |
Digital amplifier
To provide a digital amplifier advantageously performing volume adjustment over a wide range. A first and second field effect transistors include N-channel type field effect transistors. The first...
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7167047 |
Multi-channel power amplifier self-configuring to a bridge or single-ended output, particularly for audio applications
In a multi-channel amplifier switching from a single-ended to a bridge configuration, one of the two operational amplifiers of the output bridge structure of each channel is kept at the design...
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7161428 |
Method and apparatus for extending the bandwidth of a Class D amplifier circuit
Class D amplifiers are used for their high efficiency, but they have some undesirable characteristics that limit their useable bandwidth, one of these being the residual switching frequency ripple....
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7157969 |
Low distortion class D amplifier using a controlled delay
An electronic class-D amplifier including a one servo-loop amplifier plus pulse width modulator, and a controlled delay stage including a delay modulation input, and a negative feedback path...
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7157963 |
Methods and apparatus for controlling the output voltage of a switched-mode power supply
Linear power amplifiers tend to be inefficient. This is a particular problem for RF amplifiers in a cellular base station. In order to improve the efficiency of such amplifiers, attempts have been...
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7151406 |
Compensation of nonlinearity introduced by dead time in switching output stage
A method of operating a class D amplifier output stage that compensates for nonlinearity introduced by a residual load current during the dead time in the switching of the output stage. The...
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7151404 |
Current controlled pulse width modulation circuit and class-D amplifier comprising the same
A pulse width modulation (PWM) circuit comprising an input circuit, first and second controllers, and first and second Schmidt triggers. The first controller sets a first voltage level by a first...
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7151408 |
Method for generating a radio-frequency alternating voltage and an associated radio-frequency power amplifier
A radio-frequency power amplifier system operated in a resonant mode of operation includes a uniform power source, a switching element adapted for applying power on and off at a basic frequency...
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7151403 |
Adaptive self-calibration method and apparatus
Feedback for self-calibration of any parameter in an analog and/or digital system is described wherein a system quality factor can be represented by a voltage or current differential. The preferred...
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7146015 |
Frequency threshold audio activity detector
This invention is a circuit that actuates a loudspeaker at input frequencies above a predetermined threshold and mutes the loudspeaker at input frequencies below the threshold. The circuit includes...
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7142048 |
Pop sound reduction circuit and voice output amplification device
A pop sound reduction circuit comprises a pulse width modulation amplifier configured to amplify a reference voltage to an intermediate amplitude of a pulse width modulated signal, a first switch...
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7142050 |
Recovery from clipping events in a class D amplifier
A class AD audio amplifier system ( 10 ) with improved recovery from clipping events is disclosed. The amplifier system ( 10 ) includes multiple audio channels ( 20 ), each of which can be...
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7138864 |
Overcurrent protection in amplifier topologies employing DC isolation
An amplifier having output switch circuitry is described. A sense resistor is operable to transmit an output current associated with the output switch circuitry. Low-voltage circuitry is operable...
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7138859 |
Signal processing device and class D amplifier that can reduce radiation noise even if the number of channels of a digital audio signal inputted thereto increases
A class D amplifier defines different sets of resampled points A and B for channels chA and chB of an input digital audio signal, extracts an interpolation signal of the digital audio signal at the...
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7135922 |
Power supply rejection for pulse width modulated amplifiers and automatic gain control
A circuit according to the present invention improves the power supply rejection ratio for a pulse width modulated digital amplifier and can be used as a compressor and/or limiter. The circuit...
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7126416 |
Pulse amplitude modulation (PAM) method and circuit for improving the performance of a D-class audio amplifier
The present invention provides a PAM (Pulse Amplitude Modulation) method and circuit for improving the performance of a D-class audio amplifier. The D-class audio amplifier is inputted with a PWM...
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7116162 |
Reduced output topology for multi-reference switching amplifiers
A method and attendant circuitry reduces the number of regulatory and switching devices in a multi-reference switching amplifier. In the preferred embodiment, multiple independently-modulated...
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7116166 |
High fidelity, high power switched amplifier
A gradient amplifier arrangement is described that comprises a gradient amplifier power stage. The device may be employed to provide a current to a gradient coil, as in a MRI system. The circuitry...
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7113038 |
Power amplifier
A switching power amplifier of class D has a switching stage for generating a block wave signal by alternately switching the block wave signal between supply voltages. A filter ( 24, 25 ) generates...
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7113030 |
Class-D power amplifier capable of eliminating excessive response phenomenon when returning to a steady state from an abnormal state and an amplification method thereof
A class-D power amplifier, which prevents excessive response phenomenon from occurring when returning to a steady state from an abnormal state and an amplification method of the class-D power...
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7110555 |
Sound signal reproducing apparatus
A sound signal reproducing apparatus for supplying sound signals of a plurality of channels to speakers via sound amplifier circuits includes: a power supply voltage controller for controlling a...
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7102431 |
Method for generating a high-power alternating voltage that follows an input data system
Method for generating an amplified high-power alternating voltage that follows a digital input data stream in terms of shape and amplitude, preferably in the known I2S format, whereby a...
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7102426 |
Audio reproducing device and method, audio amplifier, and integrated circuit for audio amplifier
A digital ΔΣ modulated signal produced by a quantizer ( 1 c ) in a ΔΣ modulation processing unit ( 1 ) is put in to a feedback loop before inputted to a power switch ( 2 ) and converted into an...
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7088177 |
Amplifier apparatus
An amplifier apparatus includes: (a) an integrator having an input for receiving an input signal, and integrating the input signal to present an integrated signal; (b) a first comparer coupled with...
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7068097 |
High frequency high power H-bridge power amplifier
Methods and apparatus are provided for driving a power amplifier load, such as a loudspeaker. The apparatus comprises a processor-controlled drive assembly configured as an H-bridge system....
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7068095 |
Amplifier circuit
The invention is directed to an amplifier circuit based on the principle of a class D amplifier. To avoid unwanted convolution effects and to improve the power supply rejection ratio, provision is...
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7064603 |
Driving circuit and semiconductor device
A pulse generation part outputs a first ON pulse signal for turning a switching device on to a control part on based on the leading edge of a signal from the outside of a semiconductor device. The...
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7062336 |
Time-division method for playing multi-channel voice signals
A time-division method for playing multi-channel voice signals is provided to improve voice qualities of the multi-channel voice signals. The first feature of the present invention is that after...
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7057456 |
Class D amplifier
A pulse modulated signal (ei) output from a pulse modulator ( 1 ) and a feedback signal (ef) containing distortion caused by a power switch ( 3 ) are integrated in a first integrator ( 21 ) and a...
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7046080 |
Signal processing circuit
A signal processing circuit comprises a difference stage for receiving an input signal to be processed and a feedback signal taken from an output signal of the circuit. The difference stage...
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7046088 |
Power amplifier
A power amplifier for generating a sinusoidal high-frequency signal to be supplied to a load includes a current source adapted to supply a constant electrical current during a portion of a period...
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7038534 |
Class D audio amplifier and method for compensation of power supply voltage influence on output audio signal in class D audio amplifier
In a class D electroacoustic amplifier ( 1 ) without feedback loop containing a supply voltage source ( 8 ), an amplifier low-pass filter ( 14 ), a power stage ( 2 ) controlled by a pulse width...
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7034609 |
Switching circuits
A technique to implement removal of dead time control circuitry from the back-end of a digital switching amplifier system 100 and add dead time control circuitry on the front-end digital...
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7015754 |
Isolated converter with synchronized switching leg
An amplification device is disclosed providing a way of integrating a switch mode power supply and a class D amplifier (switch mode amplifier). This results in the usage of basically one magnetic...
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7005917 |
Power supply rejection technique for switching amplifier
Apparatus and methods greatly improve AC and, optionally, DC power supply rejection in a switching amplifier. The method broadly includes the steps of modulating the amplifier output with a...
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7003358 |
Audio signal processors
An audio signal processor which modifies audio signal components outside the conventional audio frequency band. The processor includes a Delta Sigma Modulator (DSM) that receives a non-interpolated...
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6998911 |
Gate control circuit with soft start/stop function
A control terminal driver circuit for a switching amplifier including a driver for each of a pair of output power transistors responsive to a PWM information signal. The circuit operates in...
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6992527 |
Digital power amplifier
A digital power amplifier has first and second switches, between a high potential power line and a low potential power line, which operate complementarily. When switching an ON switch, dead time is...
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6987418 |
Sound signal generating apparatus and method for reducing pop noise
A circuit for handling pulse width modulation (PWM) first signal and PWM second signal for outputting to an amplifier, the PWM first signal having one of a same phase and an opposite phase...
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6985034 |
Boost bridge amplifier
The main difference between the boost bridge amplifier according to this invention and state of the art class D amplifiers is in the connection of a load between a power supply and a switching...
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6970042 |
Power control for high frequency amplifiers
A method of controlling an input voltage of a high frequency amplifier includes measuring power supplied to a load, determining a first control variable for a series element disposed upstream from...
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6949978 |
Efficient broadband switching-mode amplifier
An efficient broadband amplifier. The amplifier includes a mechanism for amplifying an input signal via a high-speed switch and providing an amplified signal in response thereto. Another mechanism...
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6949973 |
Signal amplifier
There is provided a signal amplifier capable of restraining the influence of an EMI caused by a distortion of a waveform of an output signal. The signal amplifier comprises an inverter circuit made...
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6940343 |
Amplifier
Disclosed is an Amplifier ( 7 ) comprising an output driver with a first output stage ( 4 ) and a second output stage ( 5 ), where an input signal is applied non-inverted to the first output stage...
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6940351 |
Amplifying circuit for transmitter capable of reducing noise
In an amplifying circuit for a transmitter including a first switching device having one end thereof connected to a power supply, a second switching device having one end thereof connected to...
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6937095 |
Efficient, switched linear signal driver
The invention provides a switched linear amplifier for amplifying an input signal for provision to a communication medium. The switched linear amplifier includes a linear amplifier, an output...
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6937096 |
Switched-mode power amplifier integrally performing power combining
A switched-mode power amplifier is configured for performing power amplification of a plurality of signals input thereto and integrally summing (combining) those signals. Conceptually, this is...
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6922100 |
Method and apparatus for switching amplification having variable sample point and variable order correction
Disclosed is a method and/or apparatus for adjusting the sample time and order associated with a digital correction system for maximizing output power and minimizing power stage delay sensitivity...
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6922101 |
Phase shift modulation class D amplifier
An amplifier comprises a transformer comprising a primary coil and a secondary coil having a center tap on the secondary coil connected to a reference point. A constant periodic signal generator is...
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