DETECTION CIRCUIT FOR POWER FAILURE IN IN-VEHICLE ELECTRONIC CONTROL UNIT

摘要

PROBLEM TO BE SOLVED: To actuate an in-vehicle electronic control unit even when a main power supply terminal is brought into poor contact state and carry out notification of the anomaly or store information on the history of anomaly occurrences to facilitate maintenance and inspection.

SOLUTION: The in-vehicle electronic control unit 100A includes a main power supply circuit 131a that is supplied with power from an in-vehicle battery 101 through the output contact 103a of a power supply relay 103 and the main power supply terminal Vb of a connector and supplies stabilized control voltage Vcc to a microprocessor 110A. When contact failure occurs at the main power supply terminal Vb, power is supplied from the output contact 103a to the main power supply circuit 131a through a first electrical load 105 and a commutating diode 154 in a wrap-around supplying manner and notification of the anomaly is carried out or information on the history of anomaly occurrences is stored. The occurrence of the power supply in a wrap-around supplying manner is detected when the input voltage of the main power supply circuit 131a becomes lower than the supply voltage of the in-vehicle battery 101.

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