| 摘要 |
Disclosed is an overvoltage suppressing circuit for a semiconductor device connected between the poles of a DC power source and adapted to effect a switching operation. The circuit comprises: a serial circuit connected in parallel with a semiconductor device and including an overvoltage suppressing capacitor, an oscillation suppressing diode, and an impedance regulator connected in series each other, the impedance regulator being operable to change into a state of high impedance for suppressing a reverse current flowing into the oscillation suppressing diode when the oscillation suppressing diode is turned off; and a discharging device connected between a DC power source and the overvoltage suppressing capacitor for discharging to the DC power source a charge accumulated in the overvoltage suppressing capacitor when the oscillation suppressing diode is off. |
