| 摘要 |
PROBLEM TO BE SOLVED: To reduce a malfunction, save electric power, and lengthen the service life. SOLUTION: A voltage doubler rectifier circuit 3 performs voltage doubler rectification on a commercial AC power source 1 inputted through a filter circuit 2. A smoothing capacitor C1 outputs DC voltage by smoothing pulsating voltage of the voltage doubler rectifier circuit 3. A control circuit 6 controls on/off of first and second switching elements Q1 and Q2 , and switches output voltage of the smoothing capacitor C1 in a high frequency, and supplies high frequency voltage to a discharge lamp 7. Here, an operating frequency of an inverter lighting circuit 5 is set not less than 50kHz, and a preheating current of the discharge lamp 7 is set within 1.1 times a rated current in commerically lighting the discharge lamp 7. |
