Abstract: The present invention relates to an electrophotographic photoreceptor used for electrophotographic apparatuses such as copying machines, LED, LD printers, etc. and particularly to an electrophotographic photoreceptor which has an undercoat layer and uses an organic photoconductive material, and an electrophotographic apparatus provided with the photoreceptor.

Abstract: The present invention relates to a DC-DC converter, and aims at preventing a flywheel switch from being destroyed. A PWM control circuit outputs an oscillation signal in order to alternately switch between a main switch and a rectification switch, and a flywheel switch. A state detecting unit generates a control instruction signal for a controlling unit, if the DC-DC converter is powered down or if it is overloaded. The controlling unit turns off the flywheel switch by controlling a driving circuit which controls the on/off status of the flywheel switch. An electric current I.sub.Q2 flows via a parasitic diode D.sub.Q2, when the flywheel switch is turned off. With the above described configuration, the flywheel switch can be prevented from being destroyed, when the DC-DC converter is overloaded, or when an overcurrent occurs due to power-down.