| 摘要 |
PROBLEM TO BE SOLVED: To maintain the relay-on state of a power supply circuit device till a prescribed relay-off condition is established, in a failure of a control circuit which controls on/off of the relay. SOLUTION: A relay holding circuit 100 starts feeding the operation current Ion of the relay 50 in response to the control signal CNT from the control circuit 60 which controls on/off of the relay 50, generates holding current Ih passing through a node Nc and continues the feeding of the operation current Ion. Relay releasing circuits 120, 140, 160 are connected in parallel with respect to the node Nc, and each relay releasing circuit stops feeding the operation current Ion to turn off the relay 50 by pulling out the holding current Ih to the ground node to extinguish it during operation. While the relay releasing circuit 120 operates in response to the control signal HC from the control circuit 60, the relay releasing circuits 140, 160 respectively operate when a vehicle stops and the ignition switch 15 is turned off, not through the processing of the control circuit 60. COPYRIGHT: (C)2007,JPO&INPIT
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