| 摘要 |
PROBLEM TO BE SOLVED: To reduce electric power consumption by preventing the loss of booster voltage generated from a booster circuit. SOLUTION: In a case where driving of a solenoid valve SV1 is stopped for a predetermined time or more to lower control voltage VCP of a capacitor, the solenoid valve SV1 is pre-driven for a predetermined time width W1 by a pre-drive pulse set to be short for preventing the solenoid valve SV1 from operating before a first driving. The capacitor is charged upto a predetermined level by back electromotive force generated from a solenoid coil 21 of the solenoid valve 1. Then, the solenoid valve SV1 is driven by a normal drive pulse at predetermined timing. Accordingly, a field effect transistor on high side can be turned on by the control voltage VCP at a predetermined level.
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