DC-DC converter circuit, power supply selection circuit, and apparatus useful for increasing conversion efficiency

摘要

In a DC-DC converter circuit having a plurality of input terminals connected to a plurality of DC power supplies, and an output terminal, the DC-DC converter circuit includes a power supply selection section for selecting a DC power supply of lowest voltage on the condition that the voltage is not less than a predetermined voltage, and a step-down type of regulator section for converting the voltage of the DC power supply selected by the power supply selection section into a predetermined voltage lower than the voltage of the DC power supply selected by the power supply selection section, and outputting the converted voltage through the output terminal.