PREFERENCE CIRCUIT AND ELECTRIC POWER SUPPLY SYSTEM

摘要

Provided is a preference circuit (60), in which one of a system power supply (100) and a secondary battery unit (30) is selected as a selected supply source and the other is selected as an unselected supply source, and in which an electric power is supplied preferentially from the selected power supply source to the power source unit (52). The preference circuit (60) is characterized in that the unselected supply source is connected to the power supply unit (52) through a diode element (74) that can cause voltage drop and the selected supply source supplies an electric power to the power supply unit (52) without involving the diode element (84).