| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to prevent breakage of a switching element due to an overcurrent, by using a simplified circuit configuration even though an inverter is constituted with switching elements having a low breakdown voltage capacity. SOLUTION: If trouble detectors 5a, 5d detect a failure of an inverter by detecting an excessive current through current detectors 3a, 3d, a low level detected signal SD is inputted to both the input terminals of the AND gate 16. Because of this, a gate control signal SC which was at a high level previously is inverted to a low level and outputted to the AND gate 16. Thus, a low level control signal is inputted to one of the input terminals of the AND gates 6a, 6d, gate ON/OFF signal inputted from the control circuit 11 becomes ineffective, the operation of corresponding transistors 7a, 7d, and photocouplers 8a, 8d become off, and each switching elements 1a, 1d become off. |
