| 摘要 |
PROBLEM TO BE SOLVED: To prevent a flash immediately before an LED blackout in an LED power supply device comprising a DC/DC converter having a smoothing capacitor on the primary side.SOLUTION: An LED power supply device (1) comprises: an AC/DC conversion unit (10) for performing DC conversion on AC input voltage to charge a smoothing capacitor (114); a DC/DC converter (20) for changing voltage of the smoothing capacitor by switching operation of a switching element (201) on the primary side, to supply changed first secondary output to an LED (2); an input power supply detection unit (60) for detecting AC input voltage; and control units (30, 40, 50) that are configured so as to supply power to second secondary output of the DC/DC converter to drive the switching element after, and controls drive of the switching element so that a ratio of the first secondary output to the second secondary output decreases when stop of the AC input voltage has been detected. |
