Application of Full-Bridge Step-up Structure to Multiple CCFLs Driving

• Main Authors: Chih-Hao Chung, 鍾志豪
• Other Authors: Chin-Man Ho
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/28676603027445570082

碩士 === 中原大學 === 電機工程研究所 === 96 === 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.