| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a switching control circuit with an overcurrent protective function of a switching device, and a switching power source apparatus. Ž<P>SOLUTION: At the starting time and an overload time in which the output voltage of the switching power source apparatus is low, if an overcurrent state occurs, in which the ON period of the switching device becomes short and a device current not less than the current limit value of the switching device flows through the switching device, this overcurrent state is detected. A blanking period is made shorter than the blanking period that is obtained during steady operation, and the ON period of the switching device is made shorter. Hence, the device current flowing through the switching device can be made small in each pulse for the switching operation, and, at the same time, the device current is suppressed from increasing each time a pulse for the switching operation is generated. Therefore, the switching device is prevented from being deteriorated or damaged due to the device current of an allowable current value or above flowing into the switching device. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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