| 摘要 |
PURPOSE:To reduce loss and noise of a switching element so as to prevent breakage of the switching element, etc. CONSTITUTION:The second resonance capacity an the second 20 is provided in parallel to the second switching means 18 and the second bypass means 22 is provided so that in the case of turning off the first and the noise in turnoff can be 18, voltage change can be decreased, loss and noise in turnoff can be drastically reduced, and when the first switching means 16 in the case where not generated so as to reduce loss drastically. Providing a drive stop means 27 can stop drive of the second switching means 18 in the case where both-end voltage Vce2 of the second switching means 18 exceeds a prescribed voltage B0, so that flowing of overcurrent to the second switching means can be prevented. |
