US Patent 9007736 Power module

A power module includes a current sensing circuit in which a transistor includes an emitter connected to a sense emitter of a current sense element of an IGBT and a base connected to ground, a current sensing resistor including one end thereof connected to a collector of the transistor and the other end thereof connected to a common connection portion. The power module detects, as a current sensing voltage, a potential difference generated by the current sensing resistor based on the common connection portion as a reference, compares the current sensing voltage with a predetermined threshold voltage, and determines whether or not an overcurrent flows through the IGBT according to a magnitude relation therebetween.