| 摘要 |
PROBLEM TO BE SOLVED: To lower switching loss of a discharge lamp lighting device. SOLUTION: In the discharge lamp lighting device for lighting a discharge lamp 3 by converting power into a direct current power source 1 with a chopper circuit 2, a switching element Q1 is structured to be put on at a timing when an off-time voltage of the switching element Q1 constituting the chopper circuit 2 gets down nearly to a minimum, a differential circuit 7 is provided for time differentiating a voltage Vr at a detection point fitted inside the chopper circuit 2, and a result of the differentiation is inputted into a comparator CP1, whereby, an output of the comparator CP1 is reversed at a timing when a time differential value of the off-time oscillating voltage Vr of the switching element Q1 reverses from positive to negative, and the switching element Q1 is turned on by a driving circuit 9 in response to the output reversal of the comparator CP1. COPYRIGHT: (C)2007,JPO&INPIT |
