| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply device for a discharge lamp in which the light volume of discharge lamp can be controlled so as to be reduced for a prescribed period against the other period, with a simple structure, and its control method. SOLUTION: The DC voltage from a DC power supply part 21 is impressed on the discharge lamp 1 after a switching element 22 is switched with a prescribed duty and oscillation frequency by a pulse generating circuit 25 and its output is smoothed by a smoothing circuit 23. In the pulse generating circuit 25, the duty is controlled according to the output of a current control circuit 27 which operates based on a feedback signal from the current detection resistance 24, and the oscillation frequency is operated temporarily to be high by the output of the pulse frequency changing circuit 29 which is operated based on a frequency command Cf output in a part of period t in the period T of green display color. COPYRIGHT: (C)2008,JPO&INPIT |
