| 摘要 |
PROBLEM TO BE SOLVED: To eliminate waste of power by turning a semiconductor switching element on/off, depending on the difference between a terminal voltage and a reference voltage detected by a detecting means. SOLUTION: This power supply control circuit comprises a series connection of a path for supplying an output voltage VB of the power supply 101 to a load 102 and the drain D - source S of a semiconductor switch, i.e., a thermal FETQA. A drive control section for the thermal FETQA comprises a FETQB, resistors R1 to R10, a Zener diode ZD1, a diode D1, a comparator CMP1, a drive circuit 111 and a switch SW1. When a temperature sensor 121 detects the temperature rise of the thermal FETQA to a specified level or above, detection information is held in a latch circuit 122 and a gate interrupting circuit, i.e., an overhead interrupting FETQS, is forcibly turned off. As a result, power is prevented from being wasted, when overcurrent is limited.
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