| 摘要 |
PROBLEM TO BE SOLVED: To prevent a current from flowing through a switching element of a lighting circuit in the opposite direction even when a lighting device is used at a low temperature of about -40°C.SOLUTION: In a lighting device 11, a power factor improvement circuit 12 steps up a DC voltage output from a capacitor 19 and smooths an output through an electrolytic capacitor 27. A buck converter circuit 13 steps down the DC voltage output from the electrolytic capacitor 27 by a switching action of a MOSFET 28 to generate a predetermined DC current, and outputs the DC current to light LEDs 36 of an LED module 37. A diode 35 is connected between the electrolytic capacitor 27 of the power factor improvement circuit 12 and the MOSFET 28 of the buck converter circuit 13 to control the direction of a current flowing through the MOSFET 28 to one direction from the electrolytic capacitor 27 to the LEDs 36. |
