| 摘要 |
PROBLEM TO BE SOLVED: To provide a surge protective circuit for an insulating gate type transistor with improved surge-resistance for static electricity, etc., by shortening the gate charge time for operating (on) the insulating gate type transistor within a discharge period for a surge current to flow, causing no parasitic bipolar operation. SOLUTION: Zener diode group 55 are connected between the drain terminal and the gate terminal of a power MOSFET 52, which is broken down by the applied surge voltage from the drain terminal. Between the gate terminal of the power MOSFET 52 and a gate drive circuit 53, a resistor 54 for blocking current passage is provided. Between the source terminal and the gate terminal of the power MOSFET 52, Zener diode group 56 are connected, which is with a breakdown voltage lower than the gate breakdown-strength of an insulating gate type transistor, clamps a gate voltage at the breakdown of the Zener diode group 55. |
