Electronic control unit

An electronic control unit comprising:

• a microcomputer operating in a normal operation mode of the microcomputer, or in a low power operation mode of the microcomputer that consumes less power than the normal operation mode of the microcomputer;
• a power circuit operating in a normal operation mode of the power circuit, or in a low power operation mode of the power circuit that consumes less power than the normal operation mode of the power circuit, and supplying an electric power for an operation of the microcomputer;
• and
• a mode switcher switching the operation modes of the microcomputer and the operation modes of the power circuit based on an input signal from an external device, wherein
• when the mode switcher receives from the external device a switch signal for switching the operation modes of both of the microcomputer and the power circuit to the normal operation mode when both of the microcomputer and the power circuit operate in the low power operation mode, the mode switcher first switches the power circuit to the normal operation mode of the power circuit, and subsequently switches the microcomputer to the normal operation mode of the microcomputer.