Digital amplifier
AssigneePanasonic Corporation
InventorShinichi Watanabe
Life of this patent
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Abstract
The disclosed digital amplifier (200) is provided with a voltage value conversion block (220) for converting a digital value of a digital pulse width of a digital modulation block (210) to a voltage value; and an integration circuit block (230) for generating a triangular wave by way of a master clock and modulating the generated triangular wave on the basis of a signal corresponding to the value of the modulation width of digital pulse width modulation. The disclosed digital amplifier (200) is provided with a low-pass filter (260) for demodulating pulse power that has been power-amplified by way of a drive circuit (250) to analog power of an audio band, and an error amplifier (290) for computing the voltage difference between the voltage of a low-pass filter (280) and the low-pass filter (260) and amplifying thereof.
Claims5
A digital amplifier that receives a digital signal and drives a speaker directly with the digital signal, the digital amplifier comprising:
- a digital modulation circuit that performs digital pulse width modulation on digital audio data;
- a first analog audio output section that performs low-pass filtering of a pulse voltage that is output from the digital modulation circuit and outputs an analog audio voltage;
- a triangular wave generation circuit that generates an amplitude-modulated triangular wave based on a value of a modulation width of the digital pulse width modulation;
- a drive circuit that amplifies an output voltage from the triangular wave generation circuit;
- a second analog audio output section that performs low-pass filtering of a signal power-amplified by the drive circuit and outputs audio band analog power;
- and
- an error amplifier that computes and amplifies a voltage difference between a voltage of the first analog audio output section and a voltage of the second analog audio output section,
- wherein the triangular wave generation circuit adds an error from the error amplifier to a signal corresponding to the value of the modulation width of the digital pulse width modulation and regenerates a digital pulse width modulation waveform.
Dependencies are inferred from the claim text.