| US 7,474,064 B2 | ||
| Lamp driving circuit for a discharge lamp and a control method thereof | ||
| Ting-Cheng Lai, Taichung (Taiwan); and Masakazu Ushijima, Tokyo (Japan) | ||
| Assigned to Greatchip Technology Co., Ltd., Taichung (Taiwan) | ||
| Filed on Aug. 01, 2007, as Appl. No. 11/832,644. | ||
| Claims priority of application No. 95128662 A (TW), filed on Aug. 04, 2006. | ||
| Prior Publication US 2008/0030150 A1, Feb. 07, 2008 | ||
| Int. Cl. G05F 1/00 (2006.01) | ||
| U.S. Cl. 315—307 [315/291; 315/224; 315/209 R; 315/244; 315/DIG. 7] | 17 Claims |
| 1. A lamp driving circuit configured for driving at least one discharge lamp, said lamp driving circuit comprising:
a step-up transformer including a primary winding, and a secondary winding coupled electrically to the at least one discharge
lamp and adapted to cooperate with the at least one discharge lamp to form a tank circuit that generates a tank current;
a detector configured for detecting current magnitude of current flowing through the at least one discharge lamp, and outputting
a first detecting signal that corresponds to the current magnitude detected thereby; and
a controller coupled electrically to said primary winding of said step-up transformer, and to said detector for receiving
the first detecting signal therefrom, said controller generating a drive signal for driving said step-up transformer;
wherein said controller includes a capacitor, and further receives a current-setting signal, said controller configuring a
waveform of the drive signal by controlling charging of said capacitor based on a first calculation value that corresponds
to a frequency of the drive signal, a start-setting value, and a difference between the first detecting signal and the current-setting
signal.
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