| 摘要 |
PURPOSE:To hold stably a current flowing to a transistor (TR) of an output stage at no signal by providing each TR between a base and a signal input terminal of two TRs of the drive stage. CONSTITUTION:TRs Q5, Q6 are provided between the base of the two TRs Q3, Q4 of the drive stage and the signal input terminal 11. A constant current source 21, resistors R3-R6 and a constant current source 22 are connected between power supplies +B and -B. An input terminal 11 is connected to a connecting point of the resistors R4, R5 and also the collecter of TRs Q5, Q6 is connected thereto. A voltage VB1 across the resistor R5 is a voltage generated based on the potential difference generated between the base and emitter of the TRQ6 in active state and has a relation of function with a potential difference generated between the base and emitter. The current flowing to the TRs Q1, Q2 of the output stage is held stably at no signal by supplying said potential to the base of the drive stage TRs Q3, Q4. |
