Power transistor drive circuit.

摘要

A power transistor drive circuit includes a driver transistor (Q1) and a power switching transistor (Q2) connected in a Darlington configuration which receives turn-on and turn-off signals from a drive transformer (T1). A capacitor (C1) is provided for connection between the driver transistor base and the switching transistor emitter during a turn-off period such that the voltage on the capacitor hastens turn-off of the driver transistor and the switching transistor. A diode (CR3) connected between the emitter and the base of the driver transistor provides for continuing current flow from the capacitor following turn-off of the driver transistor but prior to turn-off of the switching transistor. After the switching transistor has turned off, the capacitor is recharged prior to the presence of a turn-on signal from the drive transformer.