| 摘要 |
PROBLEM TO BE SOLVED: To surely perform the lighting transfer control of a discharge lamp, without thereby causing an obstacle to the downsizing or the lowering of costs. SOLUTION: The discharge lamp lighting circuit 1 is provided with a DC-AC conversion circuit 3 for making AC conversion and boosting by receiving a DC input, and a start-up circuit 4, and controls a power output of the DC-AC conversion circuit 3 by a control means 6. The DC-AC conversion circuit 3 has an AC conversion transformer 7, switching elements 5H, 5L, and a resonance capacitor 8, and drives the switching elements by the control means 6 to resonate in series the resonance capacitor 8 and a leakage inductance component of the AC conversion transformer or an inductance element 9 connected to the resonance capacitor. When the resonance frequency at the time of light-off of the discharge lamp is made 'f1', the drive frequency of the switching element is regulated to the frequency away from the f1 and is then gradually made to approach the f1 concerning the output voltage at no load impressed before the lighting of the discharge lamp. COPYRIGHT: (C)2005,JPO&NCIPI |
