Abstract: Provided is a load drive device capable of diagnosing a failure of an output terminal of the load drive device before a charging voltage stabilizes in a configuration in which a capacitor is connected to an output terminal of the load drive device that drives an inductive load. In the load drive device according to the present invention, a capacitor is connected between a load terminal and a ground terminal, and the presence or absence of a failure of the load terminal is diagnosed on the basis of a current flowing between an internal power supply included in a diagnosis circuit and the load terminal.

Abstract: Even when a power supply relay cannot be turned off and when power supply to a microcomputer is normally cut off, fixing of the power supply relay is detected. An electronic control device 100 according to an aspect of the present invention includes a relay drive circuit 13 that controls on and off of a power supply relay 12 according to information about the on and off of power supply, an electronic circuit (first power supply system block 110, microcomputer 102) that operates at a first power supply voltage (V1) supplied from a battery 10 through the power supply relay 12, and a monitoring unit (second power supply system block 120) that monitors the first power supply voltage when the power supply is turned off, and holds a monitoring result, the first power supply voltage reflecting presence or absence of fixing of the power supply relay.

Abstract: Provided is a load drive device capable of diagnosing a failure of an output terminal of the load drive device before a charging voltage stabilizes in a configuration in which a capacitor is connected to an output terminal of the load drive device that drives an inductive load. In the load drive device according to the present invention, a capacitor is connected between a load terminal and a ground terminal, and the presence or absence of a failure of the load terminal is diagnosed on the basis of a current flowing between an internal power supply included in a diagnosis circuit and the load terminal.