| 摘要 |
PROBLEM TO BE SOLVED: To prevent voltages from being concentrated upon particular switching devices. SOLUTION: If a stop command is outputted, all signals from a control signal output circuit 17 are cut off. If only a switching device 3 is in a minimum ON-period, although an interlocking circuit 14 is turned off, an interlocking circuit 13 keeps on outputting ON-pulse signals until a minimum ON-time passes. The ON-pulse signals are supplied to the gate of the switching device 3 and, further, also supplied to the gate of a switching device 4 through an OR circuit 18. Therefore, when the switching device 3 is in an ON-state, the switching device 4 is also in an ON-state without fail. That is, if a stop command is outputted, as the minimum ON-period is predetermined, when the switching device 4 is turned off, the switching device 3 is turned on and hence the switching device 4 is protected from the application of an overvoltage. |
