Switching power supply apparatus including controller that switches a switching unit based on the amount of charge in a charge unit

摘要

A switching power supply apparatus includes an isolated converter that has efficiency characteristics in which power conversion efficiency at a rated load is higher than power conversion efficiency at a light load and that converts power-supply voltage into direct-current voltage to output the direct-current voltage; an FET that switches supply and shutoff of the power-supply voltage to the isolated converter; a secondary battery that stores the direct-current voltage output from the isolated converter; a voltage detector that detects an amount of charge in the secondary battery; and a controller that switches the FET on the basis of the amount of charge in the secondary battery.