Power module in which protection for switching element varies in dependence on active operation of the switching element

摘要

A power module includes: a drive circuit for driving an IGBT of a semiconductor element; a protection circuit for performing operation for protection of the IGBT if the collector current of the IGBT has reached a trip level; and a control power source voltage detection circuit for detecting a control power source voltage to be supplied to the drive circuit. The protection circuit changes a sense resistor from a resistor to a series circuit with resistors and if the control power source voltage drops to a level lower than a predetermined value, thereby lowering the trip level.