Abstract: In a power circuit which makes phase compensation by utilizing ESR of an output capacitor, a feedback signal based on an output voltage is supplied by a coupling capacitor to an N-channel MOS transistor on a saturated coupling side of a current mirror circuit inside an error amplification circuit.

Abstract: A stabilized power supply circuit includes a charge pump power supply circuit including four switching elements and a capacitor, and an error amplifier comparing the output voltage of the charge pump power supply circuit and a reference voltage and outputting an error signal on the basis of the difference therebetween. A current source is connected in series to the gate of a switching element formed of a MOSFET. The period during which electric charge is discharged from the gate is controlled in accordance with the error signal in order to maintain the output voltage constant.

Abstract: A control circuit for a DC/DC converter which includes a main switching element, a sub switching element, and a reactor in order to convert a DC input voltage to a DC output voltage. The control circuit comprises a clock signal generator for generating a clock signal during a blank period in which both the main and sub switching elements are off; a comparator for comparing a reference voltage and a voltage at a connection point between the main and sub switching elements and for outputting a comparison signal indicating a relation of magnitude between the reference voltage and the voltage at the connection point; and an operation mode switching section for monitoring the comparison signal at a timing corresponding to the clock signal in order to detect a voltage state at the connection point, and controlling the sub switching element in accordance with the voltage state.