Power supply system for control unit of internal combustion engine

摘要

A power supply system for a control unit of an internal combustion engine is provided which is capable of holding an engine controllable state after starting of the engine until the engine is stopped. A relay with a self holding function is inserted in a power supply line exclusively used for supplying electric power from a battery to the internal combustion engine control unit and its related devices. A relay drive and hold circuit 11 receives a relay drive signal and a main switch signal, drives and holds the relay 8 into a power supplying state as long as at least one of the main switch and the relay drive signal from an arithmetic processing section is input to the relay drive and hold circuit.