- 學位論文
應用全橋升壓型架構於多支冷陰極管的驅動
Application of Full-Bridge Step-up Structure to Multiple CCFLs Driving
摘要
摘 要 本論文提出一個全橋升壓式換流器架構來驅動冷陰極管，其架構是由一組全橋相移換流器再加上壓電變壓器所組成，並藉由壓電變壓器內部高升壓比的特性來提供冷陰極管啟動前的高輸出電壓與啟動後穩定的正常工作電壓與電流。 本文使用壓電變壓器來驅動冷陰極管，壓電變壓器比傳統電磁式變壓器在使用上具有許多優點，如它無電磁干擾、有高效率與低發熱量等優點，也因為壓電變壓器能完全的供應冷陰極管的高啟動電壓，所以很適合用來驅動冷陰極管，但是，由於壓電變壓器的功率很低，使得在驅動中或大尺寸面板的多根冷陰極管時會有燈管亮度不一致，甚至會有無法完全點亮冷陰極管的缺點。所以本實驗以長15cm的冷陰極管來實驗，經由適當的電路設計使得單一壓電變壓器可以成功的驅動多支冷陰極管，而節省了一般需用多顆壓電變壓器的成本。 本文也使用了電容均流的技術來達到燈管亮度一致的效果，並以實驗來證明。 關鍵詞：全橋換流器、壓電變壓器、冷陰極管
並列摘要
Abstract This thesis presents a concept of using a full-bridge step up structure to drive Cold Cathode Fluorescent Lamp (CCFL). This circuit is assembled as a set of inverter with a Piezoelectric Transformer (PT). By means of the high step-up property of PT, it supplies the high voltage output required for starting up CCFL and also provides the stable working voltage and current after that. In this study a PT has been used to drive CCFLs. PT has several advantages over the conventional transformers. For instance, PT does not induce EMI, it works with high efficiency, and it also results in low heat generation. PT is capable of supply sufficiently high voltage to driving CCFL, and therefore it is adequate for driving CCFL. However, owing to its low-power nature, PT could cause uneven brightness of the lamps and even fail to drive when multiple CCFLs are operated. In the experiments, some 15cm long CCFLs are used to prove that the new designed circuit can cooperate with PT to drive multiple CCFLs successfully. The balance capacitors are adapted as well to implement the driving of CCFL to obtain even brightness of the lamps. Keywords: Full-Bridge Inverter, Piezoelectric Transformer, CCFL.