| 摘要 |
When a heatsink temperature is equal to or lower than a low temperature threshold, a control unit (14) sets a second semiconductor switching device (4) to an ON state and heats first semiconductor switching devices (8a, 8b) by heat generation due to conduction loss of a heating resistor (3, 28). Thereafter, when the heatsink temperature becomes equal to or higher than a high temperature threshold, the control unit (14) sets the second semiconductor switching device (4) to an OFF state and stops heating of the first semiconductor switching devices (8a, 8b). |
