| 摘要 |
PROBLEM TO BE SOLVED: To prevent jump in costs by preventing the abnormal heat generation of a semiconductor switching device for throwing power and simplifying a heat radiation design for the semiconductor switching device. SOLUTION: While a power MOSFET 7 is turned on by the turn-on of a transistor 23, the output of a vehicle-mounted battery 2 is supplied to a DC-DC converter 8, and the power of a computer circuit 9 is turned on. The amount of voltage drop by the power MOSFET 7 is obtained by the difference between a divided voltage Vs from a first voltage-dividing circuit 16 and a divided voltage Vd from a second voltage-dividing circuit 17. A power-throw control microcomputer 19 forcibly turns off the power MOSFET 7, by turning off a transistor 23, when the difference between the divided voltages Vs and Vd exceeds a stipulated value.
|
