| 摘要 |
PURPOSE:To stably feed the normal rectangular wave AC power invariably by dividing rectangular abnormal signals, and applying the pulse width control to each portion to form a normal wave-form. CONSTITUTION:When the abnormal wave-form of a discharge lamp lighting device is detected by a current/voltage detecting circuit 12a, the AC current S1 and the AC voltage S2 proportional to the wave-form are generated and converted into the DC current and voltage signals S3, S4 by feedback signal polarity switching circuits 12b, then they are fed to a power control circuit 12c. The signals S3, S4 are finely divided, and modulated pulse widths P corresponding to divided portions are generated and sent to a DC/AC converter 3. The DC voltage corresponding to each pulse width is generated and outputted in time series on the input side of a polarity switching circuit 11c. Normal rectangular wave AC power can be stably fed invariably. |
