| 摘要 |
PROBLEM TO BE SOLVED: To realize means for deterioration diagnosis using a characteristic independent of a temperature, in order to detect the presence or absence of deterioration in IGBT and MOSFET.SOLUTION: A switching device, including a switching element in which a principal current is changed according to a control signal input to a gate terminal, includes gate voltage change means for changing the gate voltage of the switching element to a preset diagnosis voltage, when the principal current coincides with a preset reference current. The switching device further includes diagnosis means for inputting a control signal to stop the gate to the gate terminal of the switching element, or outputting an alarm, if a principal current when the gate voltage change means is operated is different from the reference current. |
