| 摘要 |
PROBLEM TO BE SOLVED: To provide an electrical supply circuit commonizing a power source relay for electrical supply of a first and a second in-vehicle electronic control device and supervising the same by the first in-vehicle electronic control device. SOLUTION: The first and the second in-vehicle electronic control devices mutually communicating via a serial communication interface circuit is supplied with electrical power from an in-vehicle battery via an output contact of a power source relay. An electromagnetic coil of the power source relay is energized via a transistor when a power source switch is closed. A first and a second micro processor are started by closing the output contact. A first watch dog timer generates self retention command signal to maintain an operation condition of the power source relay when intervals of watch dog signal generated by the first microprocessor are normal. When the power switch is turn off and the first and the second in-vehicle electronic control device complete evacuation process respectively, self retention command signal is stopped and the power source relay is de-energized. COPYRIGHT: (C)2009,JPO&INPIT
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