DISCHARGE LAMP LIGHTING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device which has good efficiency of the lamp load even when the lamp is on in the low light flux dimmer condition and can preclude darkening of the end of the lamp or its being put off in the dimmer condition. SOLUTION: This discharge lamp lighting device is structured so that a high frequency power supply 1 is connected with the primary side of a piezo transformer 6 while one end of a discharge lamp load 2 is connected with the secondary side of the piezo transformer 6. When the lamp load 2 is full lighted, the drive frequency of the power supply 1 is controlled to allow the transformer 6 to make resonance near the first resonance frequency f1 and vibrate in theλ-mode, and when lighted in dimmer condition, the drive frequency is lowered to near the second resonance frequency f2 of the transformer 6 to allow it to make resonance and vibrate in theλ/2 mode. Even when the lamp load 2 is lighted in dimmer condition, a high efficiency at the same level as the lamp load 2 is fully lighted can thereby be maintained.