| 摘要 |
PROBLEM TO BE SOLVED: To obtain a device which is equipped with an overcurrent cutting-off function and can reduce a large current in the beginning of power supply at a low temperature and make an electric conductor thin by turning on and off a semiconductor switch according to the difference between a detected terminal voltage and a reference voltage or 2nd reference voltage. SOLUTION: A semiconductor switch FET QA is switched, according to the control signal supplied to a control signal input terminal to control the power supply from a power source 101 to a heat generating load. A reference voltage generating means composed of a 2nd semiconductor switch FET QB, and a resistance Rr generates the reference voltage having voltage characteristics equivalent to those of the voltage across the semiconductor switch FET QA in the state, wherein the heat generating load is connected and generates the 2nd reference voltage when the heat generating load is below specific temperature at the time of the power supply to the heat generating load. A drive circuit 111 turns on and off the semiconductor switch FET QA, according to the difference between the detected terminal voltage and reference voltage or 2nd reference voltage.
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