| 摘要 |
PURPOSE:To speed up turning-off by providing a forward/reverse voltage clamp means between the base and emitter and connecting a fast recovery Schottky barrier diode to the emitter in series. CONSTITUTION:A positive ON signal from a base drive circuit 1 is given to a base of a Darlington transistor (TR) via a diode 9 to turn on the TR2 and the forward voltage of the diode 9 is clamped by diodes 11,4 and a Zener diode 12, the forward base current is saturated, the TR2 is not over-driven and the storage charge is hardly caused. When a negative OFF signal is fed, the voltage clamped by a Zener diode 15 and a diode 16 is fed to a Schottky barrier diode 14, which is recovered in a fast speed reversely and turned off, then the emitter current of the TR2 is interrupted, resulting that the TR2 is turned finally off at a fast speed. |
