The D when class amplifier

摘要

PPROBLEM TO BE SOLVED: To inexpensively provide a class-D amplifier failure detection apparatus for detecting a failure of a class-D amplifier without generating "pop" noise in inspection. PSOLUTION: In the class-D amplifier failure detection apparatus, a class-D amplifier Amp2 is an amplifier which when a sound signal is input, outputs a pulse signal modulated by the sound signal to a speaker Sp, and when the sound signal is not input, supplies an unmodulated pulse signal to the speaker Sp. A resistor R1 is connected to the speaker Sp in series in order to detect a signal output from the class-D amplifier Amp2 to the speaker Sp. A low pass filter F2 is connected in parallel with the resistor R1. A microcomputer 2, when the sound signal is not input, determines whether an unmodulated pulse signal is output from the class-D amplifier Amp2 to the speaker Sp or not based on an output from the low pass filter F2, and when the pulse signal is not output, detects the failure of the class-D amplifier Amp2. PCOPYRIGHT: (C)2011,JPO&INPIT