| 摘要 |
PURPOSE:To prevent reduction in luminous efficiency by not connecting a smoothing capacitor to a rectifier at the time of power source input, but by connecting it to both ends of a first switching device through a discharge lamp as well as a current limiting inductance so as to be used as a smoothed power source. CONSTITUTION:A condenser C0 and a diode bridge DB are not connected with each other. In-rush current is thus never to run at the time of power source input. Since the choke current of L1 runs in the entire region of full-wave rectification wave shape, an input power factor can be heightened. Regarding the asymmetry of lamp current, at the bottom of the full-wave rectification wave shape, the condenser C0 becomes a power source, whereby the choke L1 is not actuated and exists, however, this condition continues only for a period at the bottom, and the longevity of the lamp is not so deteriorated. Reduction in luminous efficienty of the discharge lamp can thus be eliminated. |
