| 摘要 |
PROBLEM TO BE SOLVED: To provide a power factor improving circuit that improves a power factor and can constitute a power supply that need to comply with harmonic guidelines, and also to provide an LED luminaire using the same. SOLUTION: The power factor improving circuit includes: an AC power supply AC; a rectifier circuit RC1 for rectifying the AC voltage of the AC power supply; a transformer T1 having a primary winding P1, a secondary winding S1, and a tertiary winding P2; a series circuit consisting of the primary winding of the transformer and a switching element Q1 and connecting to both output terminals of the rectifier circuit; rectifying and smoothing circuits D1, C1 that rectify and smooth the voltage appearing on the secondary winding of the transformer and supply the obtained DC voltage to a load; and a control circuit 10 that generates an on-pulse width signal having a predetermined width based on the DC voltage of the rectifying and smoothing circuit and turns on/off the switching element based on the on-pulse width signal. COPYRIGHT: (C)2011,JPO&INPIT |
