| 摘要 |
PURPOSE:To decrease the crossover distortion by increasing an idle current of an output stage in response to an output signal level only when a signal is present. CONSTITUTION:A current iD being a part of a drive current is detected by a time constant circuit 3 comprising a resistor R9 and a capacitor C2 via diodes D1, D2, impressed to a base of an idle current control transistor (TR) Q19 via an emitter follower 4 and becomes a collector current I0. When the current I0 is increased, the current of TRs Q13, Q14 and Q12 is increased, the base current of a power TRQ1 is increased, an idle current Iidle is increased so as to reduce the crossover distortion.
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