| 摘要 |
PURPOSE:To prevent abnormal heat generation of an audio output amplifier and to reduce the cost by cutting off the supply voltage of the audio output amplifier at the time of abnormal operation due to the damage or the like of the audio output amplifier. CONSTITUTION:If a negative DC voltage is applied to the output by abnormal operation due to the damage or the like of an audio output amplifier 1, a transistor TR 4 is turned on. When this TR 4 is turned on, a TR 27 is turned on also. The output of the TR 27 is connected to the abnormal detection port of a microcomputer 28 which controls a device, and an abnormality detecting circuit in the microcomputer 28 is operated to cut off the power of the whole of the device. The supply voltage of the audio output amplifier 1 is cut off simultaneously with cutting-off of the power of the whole of the device due to the microcomputer 28 to stop the operation, thereby preventing the negative DC voltage from being impressed to a speaker 3. |
