| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a protective circuit which prevents an excessive current from flowing to a switching element for drive of a solenoid when short-circuiting the solenoid, without using a coil which is disadvantageous in the aspect of physical constitution and cost. <P>SOLUTION: The switching element 13 is connected with a solenoid 14 in series, and also is driven by a drive circuit 16, and controls the power supply from a battery 12 to the solenoid 14. A detecting circuit 18 detects an overcurrent flowing to the solenoid 14, using a shunt resistor Rs. When an overcurrent detection signal is outputted from the detecting circuit 18, the drive of the drive circuit 16 is stopped. A MOSFET as a voltage drive element 17 is connected in series between the solenoid 14 and the detecting circuit 18, and a given bias voltage Vc is applied to the gate. <P>COPYRIGHT: (C)2004,JPO |
