Patent ID: 6903538

Claim:
A power supply apparatus comprising: a charge pump DC/DC converter having a capacitor for charging and discharging; and a series regulator, wherein the charge pump DC/DC converter and the series regulator are operated depending on an operation command, wherein the series regulator comprises: an input terminal into which an input voltage is inputted; an output terminal from which an output voltage is outputted; a transistor connected between the input and output terminals; an error amplifier in which an output signal from the error amplifier is inputted to a gate of the transistor; a first resistor, a second resistor and a switching element connected in series between the output terminal and a predetermined potential terminal, wherein the error amplifier has input terminals to which a reference potential and a potential at a node between the first and second resistors are inputted, and wherein the switching element is turned on or turned off based on the operation command.