| 摘要 |
PROBLEM TO BE SOLVED: To maintain constant surge voltage even if interruption current varies, by parallel-connecting a MOS gate semiconductor switching element which is operated in a non-saturated region by gate control, with a switch. SOLUTION: A MOS gate switch 9 using a MOS gate semiconductor switching element which is operated in a non-saturated region by gate control is parallel-connected with a switch 1 using a power switch element. The switch 1 is turned off to produce surge voltage through wiring inductance. When the surge voltage reaches the Zener voltage of a voltage judgment circuit 10 using a Zener diode, a voltage is applied to the gate of the MOS gate switch 9 to shift the MOS gate switch 9 to a non-saturated operation region. As a result, the MOS gate switch 9 keeps the surge voltage of the switch 1 constant by Zener voltage. |
