| 摘要 |
PROBLEM TO BE SOLVED: To improve detecting performance by introducing a different detecting means from conventional current detection. SOLUTION: The switching element failure detecting circuit 50 comprises: a transformer 32 in which an alternating current transmitting signal I1 flows to a primary side; a pair of switching elements 33a, 33b separately provided on a secondary side thereof and sharing an on/off control signal S1; and a failure distinguishing portion 57 distinguishing the presence/absence of failure related to the switching element 33. When both witching elements 33a, 33b have a parallel diode D1, in a collating path making a circuit through the switching elements 33a, 33b while avoiding the transformer 32 and a load 35, collating circuits 51 to 53, 54 to 56 intending to make direct current collating currents Ia, Ib flow in an opposite direction to the diode D1, are respectively provided on the switching elements 33a, 33b. The failure distinguishing portion 57 carries out failure determination on the basis of detection values J3, J4 of the collating circuits Ia, Ib and the control signal S1. COPYRIGHT: (C)2007,JPO&INPIT
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