| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an LED lighting device which prevents unstable lighting of an LED under low lighting control (low degree of lighting control), and prevents unstable operation of a power-factor improvement circuit. <P>SOLUTION: An LED lighting device 100 comprises a rectifier circuit 2, a power-factor improvement circuit 3 having two PFCs each consisting of a coil 33, a switching element 34 and a diode 35 connected in parallel with the output end of the rectifier circuit and operating independently under control to output a power having a power factor improved by the operating PFC, a constant current source 4 connected with the output end of the power-factor improvement circuit 3 and an LED module 5 and supplying a substantially constant current to the LED module 5 by constant current control, and a power-factor improvement controller 39 which receives a degree of lighting control instruction for instructing the degree of lighting control, selects a PFC to be operated out of two PFCs of the power-factor improvement circuit 3 depending on the degree of lighting control, and operates the PFC thus selected. <P>COPYRIGHT: (C)2013,JPO&INPIT |
