Power supply device for vehicle

摘要

A power supply unit is provided between a car-carried battery and load units, such as a light control unit. The power supply unit is connected to the load units through a multi-signal line. The power supply unit calculates a consumption current consumed by the load unit using an operating state of the load unit which is received through the multi-signal line from the load control unit associated with the load unit. The power supply unit compares the calculated consumption current with a supplying current supplied form the battery. If the supplying current is excessively large, the power supply unit interrupts the supply of current from the battery to the load unit. Therefore, the power supply device can detect a phenomenon, for example, a rare short of an extremely short shorting time.