| 摘要 |
PROBLEM TO BE SOLVED: To supply a DC output to a load, also supply an AC output to a discharge lamp, enhance the efficiency, and reduce a cost and a size. SOLUTION: A switching power supply converts a DC voltage from a DC power supply Vdc1 into a high-frequency voltage by turning on/off a switching element Q1 connected to the primary winding 5a of a transformer T, converts a high-frequency voltage in a secondary winding 5b into a DC voltage by rectifying/smoothing circuits D1, Co, and supplies it to a load RL. The power supply is provided with a resonance circuit having a reactor Lv and a capacitor Cr connected across both ends of a tertiary winding 5c in series, a plurality of voltage boosting transformers T1-Tn respectively having a primary winding 7a connected across both ends of a capacitor Cr and a secondary winding 7b, a plurality of cold-cathode tubes 11<SB>1</SB>-11<SB>n</SB>corresponding to a plurality of the voltage boosting transformers T1-Tn and connected across both ends of the secondary winding 7b, and a control circuit 3a for controlling currents flowing in a plurality of the cold-cathode tubes 11<SB>1</SB>-11<SB>n</SB>by adjusting a switching frequency. COPYRIGHT: (C)2006,JPO&NCIPI |
