| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power supply which can protect a switching device from overcurrent, even if a DC input voltage is lowered. SOLUTION: In a switching power supply having a switching transistor Q1 whose ONs/OFFs are controlled, to have a DC output voltage supplied to a load 5 be a prescribed value, there is provided an ON/OFF operation stopping circuit 3 which stops the ON/OFF operation of the switching transistor Q1, regardless of the value of the DC output voltage when a voltage between both terminals of a smoothing capacitor, i.e., a DC input voltage, is lowered to a value smaller than the prescribed value. COPYRIGHT: (C)2003,JPO
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