| 摘要 |
PURPOSE:To prevent the production of unnecessary protective operation, by approaching the operating point to protect the output transistor to ASO line. CONSTITUTION:With a transistor 19 on, when a voltage between collector and emitter fed to the transistor exceeds the power supply voltage, a diode 13 is off, a transistor 15 is on and the input voltage of a transistor 3 is interrupted. Accordingly, the collector current of the transistor 3 to turn on the transistor 15 can be obtained from resistors 5, 9, 17, and the operating point for protective operation can be made to the protection line C closer to the ASO line A. The protection line has a cross point S with the ASO line, if nothing is done. The protection line C is made in coincidence with the conventional protection line B, by adjusting resistors 21, 23 so that transistors 19, 20 can be off on the cross point S, for this purpose. |
