本文主要針對LED TV背光設備研發設計一個照明用的電源轉換器，此電源轉換器的特色是具備主動功因、高效率AC/DC轉換及定電流LED驅動器。電路架構為升壓轉換器和半橋式LLC諧振轉換器之組合並操作於不連續導通模式下，二次側再加上定電流電路使得LED模組達到恆流，並加上調光的控制使其輸出亮度可以調整。本論文所使用的主動式PFC轉換器操作在邊界模式，它將90V~264V的交流電轉換成390V的直流電，再搭配高效率的半橋轉換器將電壓轉換成70V電壓供給LED燈管，在二次側使用定流電路將LED電流恆流，使其達到高效率低耗能定電流的LED驅動電路。確定整個電路架構後，對轉換器做數學式動作推導並計算出元件參數，然後與實際結果做其驗證，並確定其可行性。最後，依據本論文之操作原理及分析設計，製作一組六燈管之LED驅動電路，其規格為Vi=90~264Vac，VLED=70V，ILED=240mA，測量該電路之相關波形及數據來驗證本文之理論。 This thesis is mainly developed and focused on a power converter for LED TV backlight lightening. Its feature is possessing active power factor and high efficiency AC-DC converter and constant current LED driver. The circuit architecture combines boost converter with LLC half bridge resonant converter and it works under the model of discontinuous conduction mode as well. Moreover, its secondary stage has constant current circuit which provides constant current for LED modules. Furthermore, the illumination can be adjusted by dimmer. An active PFC and operation in boundary mode is used in this study. It converts AC 90V~264V to DC 390V and follows convert voltage to 70V for LED light bar by high efficiency half bridge converter. In secondary side, it is used by a constant current circuit to provide LED current with high efficiency and low power dissipation and constant current. In addition, mathematical calculation is used to derive and extract the parameters of this converter. Finally, a six-light-bar-LED demo board is realized for this study. The main spec are Vi=90~264Vac，VLED=70V，ILED=240mA. Waveforms and related data are measured to verify and support this study.
