Electronic Control Device, In-Vehicle System, and Power Supply Device

A transient increase or decrease of power supplied to a reconfiguration circuit to be a logic circuit whose circuit configuration can be changed is reduced. An autonomous traveling control ECU has a reconfiguration circuit a main power supply circuit an auxiliary current source circuit and a function control unit The reconfiguration circuit is a reconfigurable logic circuit. The main power supply circuit supplies a power supply voltage to the reconfiguration circuit The auxiliary current source circuit increases or decreases a current supplied from the main power supply circuit to the reconfiguration circuit The function control unit determines an operation mode of the reconfiguration circuit on the basis of a mode determination signal input from the outside and indicating a traveling mode of a vehicle, and controls a reconfiguration of the reconfiguration circuit on the basis of a determination result. The auxiliary current source circuit increases or decreases the current supplied to the reconfiguration circuit in accordance with a load variation of the reconfiguration circuit on the basis of an auxiliary current control signal for giving an instruction on an increase or decrease of the current supplied to the reconfiguration circuit