| 摘要 |
PURPOSE:To keep a stable discharge state by inputting a plurality of booster voltages and oscillating frequencies suitable for lighting and light controlling according to each of different lamps to one control circuit, and selecting and switchingly using them. CONSTITUTION:An oscillating frequency driving circuit 5 and a booster voltage driving circuit 6 are interlocked by a control circuit 10, and when the light control degree is increased, they are controlled in such a manner that the booster voltage of a booster circuit 3 is reduced, and the oscillating frequency of an inverter circuit 4 is enhanced. Several kinds of discharge lamps 9 are available, and characteristics such as lighting voltage and discharge keeping voltage at light control are differed depending on the kind of the lamps. Therefore, to a target lamp to be used, a proper control characteristic data is set from the outside of various related data of booster voltage and oscillating frequency. Thus, various kinds of lamps can be properly controlled with one control circuit or an IC for control. The under light control is never caused, and the life of the lamp can be extended. |
