| 摘要 |
PURPOSE:To prevent the output transistor from being destroyed, by providing a diode to prevent a reverse current in a circuit for seting idling current. CONSTITUTION:An idling current set circuit 109 of an output stage transistor determines the bias voltage by taking the output point of an amplifier in BTL connection, to flow almost a given current to output transistors Q3-Q6. The idling current set circuit 109 includes a reverse current preventing diode D8. If a speaker of another channel is connected to the output terminal, the inversion of current which may cause destruction, through the idling current set circuit 105 is prevented for one of transistors forming the output of a half wave, which can not be compensated by an ASO detection circuit only. |
