Power semiconductor device, power arm and inverter circuit

摘要

It is an object of the present invention to provide an inverter circuit including a power arm ensuring a high breakdown voltage and having low probability of malfunction. In a power arm element consisting of a switching element and a diode connected in inverse-parallel connection thereto, n free wheeling diodes (n>=2) connected in series are connected in inverse-parallel connection to a switching element (1b). A breakdown voltage between an anode and a cathode of each free wheeling diode is defined to be 1/n of a breakdown voltage of the switching element (1b). That is, the breakdown voltage of each free wheeling diode is reduced to 1/n to reduce a thickness of a n- drift region. A transient voltage characteristic during flow of a free wheeling current can be thereby kept low. The drop in the breakdown voltage is compensated with the n free wheeling diodes connected in series, to thereby ensure breakdown voltage of a degree approximately the same as that of the switching element.