| 摘要 |
PROBLEM TO BE SOLVED: To simply and surely eliminate DC components included in an analog signal output from a 1-bit digital amplifier without having to perform digital processing. SOLUTION: A digital power amplifier for audio comprises a PWM (pulse width modulation) part 112 for a digital audio input signal; a gate part 115 having a pair of gate elements 115a, 115b; a dual polarity power supply part 130 for supplying a prescribed voltage to the gate part 130; a gate driver section 114 for on/off controlling of the gate part 115, based on the output signal from the PWM part 112; and a low pass filter 116 for extracting an analog signal B form a digital output signal A output from the gate part 115 to supply to a loud speaker SP, extracts DC components from the analog signal B to supply to the power supply 130 and controls a power supply voltage -V<SB>out</SB>on a negative side of the power supply 130 so as to make the DC components small. COPYRIGHT: (C)2004,JPO
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