| 摘要 |
PROBLEM TO BE SOLVED: To prevent erroneous function by an arrangement wherein the function for interrupting the semiconductor switch of a logic circuit is disabled for a second short time even if a current exceeding a predetermined level is detected by a current detection circuit when the semiconductor switch is conducting over a sufficiently long time. SOLUTION: When a refrigerator is turned on by an automatic switch, for example, it is detected by a control circuit 5 through a current detection circuit 2 and a logic circuit 4. Since the current level exceeds an overcurrent set level, the logic circuit 4 turns off a semiconductor switch 1. Overcurrent detection is finished here in case of a conventional system, but that function 15 regarded normal in the inventive system. The control circuit 5 actuates a second means to set the number of times (n) at 1 and then turns the semiconductor switch 1 on/off (n) times while incrementing (n) by 1 at a time. If the overcurrent set level is not exceeded during that interval, a decision is made that the function is normal and execution of the second means is ended before entering into a stabilized power supply state again.
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