| 摘要 |
PROBLEM TO BE SOLVED: To provide a protection device of a semiconductor device for protecting, from an overcurrent, a semiconductor device for controlling a load, that is electrified in a predetermined duty ratio to operate when a voltage is applied. SOLUTION: A power MOSFET (Q1), in which ON resistance at 150°C satisfies an expression (7), is used as a semiconductor device for controlling load drive and stop. Furthermore, a monitor voltage VMO in proportion to a load current IL is generated by a monitor voltage generating circuit 13, and the monitor voltage VMO is compared with first to fourth reference voltages Vref1 to Vref4, to set the number of points for changing a cumulative count value of a counter. Therefore, as a degree of the overcurrent is increased, the cumulative count value speedily reaches an upper limit count value 255, so that the semiconductor device is shut off to protect the load circuit. COPYRIGHT: (C)2011,JPO&INPIT
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