| 摘要 |
PROBLEM TO BE SOLVED: To provide an amplifier by increasing the processing speed of a signal in a level shift circuit so as to suppress the occurrence of distortion in an audio output signal. SOLUTION: Capacitors 61, 66 eliminate the DC component of a PDM signal from a waveform shaping circuit, setting the DC voltage level of signal lines 73, 74 by diodes 62, 67 and resistors 65, 70 on the basis of the power supply voltage of a switching element drive circuit changes the DC voltage level of the PDM signal on the signal lines 73, 74 into a DC voltage level at which the switching element drive circuit is operable. Since the level of the PDM signal is shifted without using a switching element in this way, the processing speed of the signal in the level shift circuit can be increased. COPYRIGHT: (C)2004,JPO
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