Class D amplifier and method
AssigneeHarris Corporation
InventorHarold Allen Wittlinger
Life of this patent
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Abstract
A Class D (audio) amplifier and method in which an input signal for the amplifier is pulse width modulated outside of the amplifier's feedback loop, and in which the pulse width modulated input signal and a pulsed signal from the feedback loop are summed in the feedback loop and fed back to the amplifier. The removal of the pulse width modulation stage and signal integration stage from the feedback loop improves distortion.
Claims13
A pulse width modulated digital audio amplifier having a continuous analog feedback loop which does not include an integrator.
A pulse width modulated digital audio amplifier having a continuous analog feedback loop which does not include a modulator.
A pulse width modulated audio amplifier having an input terminal and an output terminal;
- a source of an analog audio input signal;
- means for pulse width modulating the output signal from said source to thereby provide a pulse width modulated digital signal in which the width of the pulses is related to the analog audio input signal;
- a feedback circuit including an inverter;
- and
- a summing amplifier operatively connected to receive the output signals from said modulating means and from said inverter.
A pulse width modulated digital audio amplifier having an output terminal;
- a source of a pulse width modulated digital audio input signal;
- a resistive summing junction operatively connected to receive the signal from said source;
- and
- amplifying means including at least one invertor for connecting said summing junction to said output terminal.
A dual channel, pulse width modulated, audio digital amplifier having two output terminals;
- a source of first and second audio input signals;
- means for pulse width modulating the signals from said source;
- and
- feedback means including at least one invertor for each channel for summing the output signal from one of said output terminals with the output signal from one of said modulating means.
A method of reducing the distortion of a pulse width modulated, continuous analog feedback, audio digital amplifier comprising the step of eliminating all integration from the feedback path.
A method of reducing the distortion of a pulse width modulated, continuous analog feedback, audio digital amplifier comprising the step of eliminating all modulation from the feedback path.
A method comprising the steps of:
- (a) providing an analog audio input signal;
- (b) pulse width modulating the analog audio input signal to provide a digital input signal in which the width of the pulses is related to the audio in the analog audio input signal;
- (c) driving a speaker with a pulse width modulated digital output signal derived from the pulse width modulated digital input signal;
- and
- (d) summing the pulse width modulated digital output signal with the pulse width modulated input signal to correct non-linearities.
Dependencies are inferred from the claim text.