| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device which can adjust the power of a discharge lamp from an AC secondary side continuously and which is convenient to adjust. SOLUTION: This is a discharge lamp lighting device which comprises a high pressure discharge lamp 4, a chopper circuit 2 for carrying out switching operation of the voltage inputted to the power supply input terminal 1 by a pulse-width modulation control signal, an ignitor 3 for starting the high pressure discharge lamp 4 by generating a high voltage pulse, a lamp power operational circuit 9 for outputting a voltage corresponding to the lamp power, and a pulse-width modulation control circuit 8 for controlling the chopper circuit so that it may be equal to the output voltage of the lamp power operational circuit 9. A DC conversion circuit 5 for outputting a pulse for controlling the power and a low pass filter 7 for changing the pulse from the DC conversion circuit 5 inputted through an insulated circuit 6 into DC voltage are provided, and the reference voltage of the pulse-width modulation control circuit is made as the output voltage of the low pass filter. COPYRIGHT: (C)2005,JPO&NCIPI |
