Abstract
Due to the rapid progress of liquid crystal display (LCD), the thin film transistor (TFT) LCD market has a remarkable increase. Naturally, the corresponding necessity of the electronic ballast for the cold cathode fluorescent lamp (CCFL) as the backlight module of the LCD will increase greatly as well. As a result, many related researches are undergoing to enhance the performance and reduce the cost of the ballast. In view of the above objectives, a novel single stage ballast topology is first proposed in this thesis such that much wider input DC voltage range can be tolerated to allow the application of different energy sources. In addition, instead of using four active power semiconductor switches, only two are required in the new topology. Hence, better efficiency and lower cost can be achieved. In addition, a design methodology is also proposed in this thesis to provide a systematic approach for designing the ballast. By this way, the conventional try and error approach can be obviated. Thirdly, an integrated closed loop controller is proposed for stabilizing the new ballast. A small signal model is also delved for derived the proper parameters of the controller without losing the stability. Finally, a burst mode dimming controller is also integrated for adjusting the light intensity with full range without incurring any temperature phenomenon. A hardware prototype is also constructed for demonstrating the feasibility of the proposed single stage ballast for the CCFL.