The power supply circuit

an operational amplifier generates a power supply potential from a reference potential. An impedance adjuster adjusts an output impedance of the operational amplifier in accordance with a control signal. A charge accumulator accumulates an output charge of the operational amplifier whose impedance is adjusted by the impedance adjuster. A comparator compares an output voltage of the operational amplifier before the impedance adjustment by the impedance adjuster and the output voltage of the operational amplifier after the impedance adjustment by the impedance adjuster to each other, and the comparator further generates the control signal in accordance with a result of the comparison so as to output the generated control signal to the impedance adjuster.