| 摘要 |
PROBLEM TO BE SOLVED: To enhance power factor and remarkably reduce power source current harmonics by dynamically constituting switching, so that an inverter power source forms a series circuit of a capacitor in a charging circuit and a smoothing capacitor in a smoothing circuit. SOLUTION: When an FET (switching element) 11 of an inverter circuit 9 is turned on, an FET 3 of a charging circuit 2 and an FET 5 of a smoothing circuit 4 are turned on, the output voltage of a rectifying circuit 1 is applied to the charging circuit 2, and a pumping capacitor C1 is charged via a choke coil L1. After charging to the pumping capacitor C1 is completed, when an FET 6 of the smoothing circuit 4 and an FET 10 of the inverter 9 have been turned on, the pumping capacitor C1 and a lamp circuit 7 are joined, and current flows from the pumping capacitor C1 to the lamp circuit 7. Supply voltage is heightened, compared with the conventional device, and Q-value of a resonance circuit necessary to obtain lamp voltage required for lamp starting is made small. |
