| 摘要 |
PURPOSE:To prevent the saturation of an output transistor on control side without remarkably increasing the number of elements, which constitute a circuit, or setting the voltage for preventing the saturation, having a margin. CONSTITUTION:Transistors Q19, Q20, and Q21 are provided on the base side of output transistors Q1, Q3, and Q5 on saturation side. Saturation control voltage Valpha is applied through a diode Q22 to the bases of the transistors Q19, Q20, and Q21. The collectors of the transistors Q19, Q20, and Q20 are connected to the base of the transistor Q23. The transistor Q23 leads a current hfe times the current supplied to the base into the earth from the output of a current feedback amplifier 64. When the drive of the output transistors 1, Q3, and Q4 on control side increases and the output of the current feedback amplifier 64 increases accompanying it, the current being led in the earth by transistor Q23 increases, and the driving current being distributed to the output transistors Q1, Q3, and Q5 on control side from an above and below distributing circuit 60 decreases. |
