摘要 |
When an abnormality occurs in a supply circuit and its output is decreased, a protect circuit detects the abnormality and outputs a protect signal to an audio circuit. The audio circuit upon detection of the protect signal stops outputting audio so that outputting of an audio noise due to a deficiency in the supplied voltage is prevented. Meanwhile, when no abnormality occurs in the supply circuit, a microcomputer controls the audio circuit by supplying it with such a signal as to allow it to output an audio, or to increase the audio volume, or with a mute signal.
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