Patent ID: 8213146

Claim:
A semiconductor power conversion apparatus including an Insulated Gate Bipolar Transistor (IGBT) type semiconductor, comprising: an overvoltage protection circuit connected between a collector of the IGBT type semiconductor and a gate thereof, wherein the overvoltage protection circuit includes a plurality of clamping elements connected in series with breakdown directions thereof aligned in the same direction, a cathode side terminal of the series connected plurality of clamping elements being connected to the collector of the IGBT type semiconductor, while an anode side terminal of the series connected plurality of clamping elements being connected to the gate of the IGBT type semiconductor, a first resistor disposed to form a direct connection therethrough between the gate of the IGBT type semiconductor and a junction conductor that interconnects the plurality of series connected clamping elements, the first resistor being connected such that when a collector-gate voltage of the IGBT type semiconductor exceeds a first breakdown voltage relating to a part of the plurality of the clamping elements that is disposed on the collector side of the IGBT type semiconductor, a current flows from the junction conductor through the first resistor, and a second resistor directly connected at one end thereof to the gate of the IGBT type semiconductor and at a second end thereof to the junction conductor via another part of the plurality of the clamping elements that is disposed on the gate side of the IGBT type semiconductor between the gate of the IGBT type semiconductor and the junction conductor, the second resistor being connected such that when a collector-gate voltage of the IGBT type semiconductor exceeds a sum of the breakdown voltages relating to the plurality of the clamping elements, a current flows from the second resistor via the another part of the plurality of clamping elements that is disposed on the gate side of the IGBT type semiconductor, in addition to the current flowing from the first resistor, wherein the second resistor is set to a resistive value larger than that of the first resistor.