| 摘要 |
A multi-lamps LCD back-light control circuit comprises a control unit, an full bridge switch, a resonance network circuit, a voltage transformer, a lamp, and a feedback network. A constant operating frequency and a pulse width modulation (PWM) feedback are used to control the CCFL current. The back-light control circuit is such that a power switch of the full bridge switch outputs a duty cycle that is controlled and changed via a PWM controller of the control unit, while a ground switch of the full bridge switch outputs a constant duty cycle controllable above 50%.
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