Patent ID: 8102686

Claim:
An electric power supply circuit, comprising: a rectifier circuit, coupled to an alternating current power supply, for rectifying an alternating current; a switching element for causing, when being turned ON, a short-circuit for output power of the rectifier circuit; and a PAM control section configured to output, with a predetermined timing based on a zero-cross point of an input voltage of the rectifier circuit, a single timing pattern of a fixed width, including a plurality of ON/OFF pulses during each half period to cause the switching element to perform switching so that a waveform of the input current approximates to a sine wave, wherein the PAM control section is configured to output only the single timing pattern in which an OFF pulse is output first based on the zero-cross point, and subsequently, the ON/OFF pulses are output alternately, and the PAM control section is configured to output an ON pulse extending over the zero-cross point of the input voltage of the rectifier circuit and two or more ON pulses generated both before and after said ON pulse extending over the zero-cross point during each half period of the input voltage.