| 摘要 |
PROBLEM TO BE SOLVED: To provide an overload detecting method, an overload detection circuit, a protection method, and a protection circuit capable of surely protecting a power supply MOSFET on supplying power to a load or the like with high reliability. SOLUTION: The overload detection circuit 20 is provided with: a dummy load 31 with a resistance in response to an overload decision criterion and a FET 33 for detecting an overload, which are placed in parallel with a load 21 and a FET 23 for controlling the power supply, a comparator 35 compares source voltages of both the FETs 23, 33, when the source voltage of the FET 23 is lower than the source voltage of the FET 33, and the comparator 35 decides occurrence of the overload and activates a chopper circuit 37 and a voltage regulation circuit 39 to suppress a current passing through the FET 23. COPYRIGHT: (C)2004,JPO&NCIPI
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