| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device in which audible noise due to mechanical vibration of a ferrite core is reduced. <P>SOLUTION: A DC-AC inverter circuit 2 converts a DC voltage into an AC voltage of an arbitrary switching frequency. The AC voltage thus converted is applied to an LC series circuit of an inductor L1 where a coil is wound around a ferrite core and a capacitor C1. In steady operation, a digital control circuit 3 controls on/off of switching elements Q1-Q4 at a switching frequency of a steady frequency. A discharge lamp is connected across the capacitor C1. The digital control circuit 3 controls the switching frequency to be lower than the steady frequency when the temperature of the ferrite is lower than a predetermined temperature. <P>COPYRIGHT: (C)2012,JPO&INPIT |
