overvoltage protection circuit for MOS power semiconductor switch

摘要

The protection circuit has a voltage clamping stage (10) in parallel with the collector-gate path of the power semiconductor switch (T3), provided with a measuring resistance (Ro3), supplying a measuring signal to a regulator (16). This is connected on the output side to a control input (20) of the control stage (2) for the power semiconductor switch. Pref. the voltage clamping stage uses a diode (V22) biased in the direction of the switch gate and at least one oppositely-based Zener diode (V11,...V14), with the measuring resistance inserted between them.