Patent ID: 7781982
Filing Date: 2010-08-24
Classification: H05B

Abstract:
1. A low-voltage power supply circuit for supplying a low-voltage power supply for illumination, comprising: a rectifier circuit for rectifying an ac power supply; a power-factor control circuit for controlling rectified output from said rectifier circuit, said power-factor control circuit being composed of a step-down circuit, and moreover, being provided with a current-limiting capability, a switch element that is both driven by the output of said rectifier circuit and the detected output of a power supply current and switched by the control output from said power-factor control circuit; a step-down transformer that is controlled by the output of said switch element; a output circuit for both rectifying the output of said transformer and filtering the high-frequency component by means of a passive element; and a current detection circuit for obtaining the detected output of said power supply current from the output current of said simplified output circuit.