| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to carry out operation of power breaking always normally for an electronic unit on a vehicle at low cost with low power consumption. SOLUTION: When a potential level of an accessory terminal ACC is increased according to operation of an ignition switch, a second transistor 14 and an FET 9 are turned on, thereby feeding an electronic unit 1 on a vehicle with power from an output terminal +B of a vehicle battery through a power supply IC 8. After the power is made, the power supply itself is held while a microcomputer 2 in the electronic unit 1 on the vehicle turns on a first transistor 12 on the basis of a signal from an output port P1. When the ignition switch is turned to an off position, the operation of the electronic unit 1 is finished normally by the microcomputer 2, and at the same time the first transistor 12 and the FET 9 are sequentially turned off after a given time necessary for warning operation of an IC card 4, if not slid out, goes by. Then, the power for the electronic unit 1 is turned off. |
