| 摘要 |
PURPOSE:To prevent a switching element or the like from its destruction at the time of abnormality in a power supply while reducing the loss and noise of the switching element. CONSTITUTION:The second resonating capacitor 20 is provided in parallel to the second switching means 18, and further the second bypass means 22 is provided. In this way, a voltage change can be decreased at turn off time of the first/second switching means '161 18, and loss and noise at the turn off time can be markedly reduced, also not to generate a turn on at on time of the first switching means 16 but to attain the substantial reduction of the loss. Further by providing an abnormality detecting means 26 and an abnormality time drive control means 27, the fear of destructing the second switching means 18 or the like by excessively increasing voltage VCE2 across both ends of the second switching means 18 can be eliminated. |
