| 摘要 |
PROBLEM TO BE SOLVED: To provide a rush current suppressing circuit which can effectively suppress rush currents, which flow when power failures are restored as well as when power supply is turned on. SOLUTION: A rush current suppressing circuit is provided with power thermistors TH1 and TH2, which are connected in series with the AC power input line of a power unit and suppress rush currents; switch circuits 13 and 14 which are connected in parallel with the thermistors TH1 and TH2, short- circuit the thermistors TH1 and TH2, and cancel the short-circuiting of the thermistors TH1 and TH2; a diode bridge circuit 11 which is connected to the AC power input line, detects the presence of AC power, and when the AC power presents, controls the successive short-circuiting of the switch circuits 13 and 14. The rush current suppressing circuit is also provided with a current suppressing element control circuit composed of a voltage-detecting circuit 12.
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