| 摘要 |
PROBLEM TO BE SOLVED: To prevent DC output in a chopper circuit, immediately after lighting, from causing ringing, and to achieve a stable lit state. SOLUTION: A discharge lamp lighting device comprises a preheating and starting time measuring unit 7 for measuring the elapsed time of a preheating period T1 and a starting period T2 and a command value change indicating unit 8 for giving indication to a chopper control unit 4, so as to gradually increase a command value Vdcs in the starting period T2 having a comparatively gentle inclination. In the starting period T2, the chopper control unit 4 controls DC output voltage Vdc, so as to gradually increase from a value Vdcp upon preheating at a constant gradient dVdc/dt, in accordance with a command value Sdcs(t). Thus, the command value will not change rapidly unlike in the prior art, so that ringing will not occur on the DC output voltage Vdc in a chopper circuit 1, when the starting period T2 is completed into a lighted state, whereby a discharge lamp La can be lit stably without flickering. |
