Patent ID: 7276887

Claim:
A power supply circuit that is supplied with at least one of a first power supply voltage and a second power supply voltage from an external power source and outputs a desired power supply voltage, the power supply circuit comprising: an output terminal; a first power supply circuit that is powered by the first power supply voltage and includes a first voltage generation circuit for outputting a first output voltage that changes with an output current from the first voltage generation circuit and a first output circuit for outputting a second output voltage to the output terminal based on the first output voltage; a second power supply circuit that is powered by the second power supply voltage and includes a second voltage generation circuit for outputting a third output voltage, a differential amplifier circuit for outputting a fourth output voltage based on a difference between the third output voltage and a feedback voltage from the output terminal, and a second output circuit for outputting a fifth output voltage to the output terminal based on the fourth output voltage; and a current sink circuit into which the output current flows based on the fourth output voltage.