| 摘要 |
PURPOSE:To reduce crossover distortion in a push-pull Darlington-connected amplifier by making a bias voltage different between a class ''A'' and a class ''B'' operation region. CONSTITUTION:The push-pull power amplifier consisting of driving transistors (TR) Q3 and Q4 and output TRs Q1 and Q2 is provided with current mirror circuit 1 and 2 and the bias compensating circuit composed of TRs Q5 and Q6, diodes D1 and D2, and resistances R1, R2 and r2. The bias compensating circuit applies the difference voltage between base-emitter voltages of the TRs Q1 and Q2 in the class ''A'' operation region or the voltage obtained by subtracting the sum voltage of base-emitter voltages of the TRs Q1 and Q2 or Q2 and Q4 from the sum voltage of a bias voltage and a voltage proportional to an input voltage as a voltage drop (bias compensating voltage) across a resistance R31 or R32 in the class ''B'' operation region. |
