Dead-Time-Modulated Synchronous PWM Controller for Dimmable CCFL Royer Inverter

G.-C. Hsieh, C.-C. Chu, and P.-S. Hsu (Taiwan)


DTM-PWM controller, Current-fed Royer inverter, CCFL, Buck converter


Synchronous PWM controller achieved by dead-time modulation is explored for self-oscillation Royer inverter. The dead-time-modulated PWM (DTM-PWM) controller is composed of a monostable circuit and a constant-current charger (CCC). The presented switching period for buck regulation consists of a referred sawtooth with constant-period and a dead-time. The synchronizing strategy is conducted by modulating the dead-time according to the resonant frequency of the Royer inverter. Two kinds of the control strategies in DTM-PWM controller are explored including down-going and up-going error voltage controls. A DTM-PWM controlled dimmable Royer inverter with two-CCFL by primary-side control is designed and realized. Two kinds of the used controllers for Royer inverter are also experimented and compared with the proposed DTM-PWM controller. The results of analysis and theoretical prediction are verified with experiments.

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