- 學位論文
液晶電視整合型電源供應器之研製
Study and Implementation of Integrated Power Supply for LCD TV
摘要
本論文為結合兩段式功率因數修正交流-直流轉換器和直流-交流換流器之研制，其中交流-直流轉換器部分，製作兩段式昇壓功率因數修正器，以150Vac輸入時為臨界點，於90~150Vac輸入時僅昇壓至230Vdc，150~264Vac輸入時才昇壓至400Vdc，以提昇傳統單段昇壓功率因數修正器在較低交流電壓輸入時之效率，並降低主要功率元件之溫度，本論文採用ST公司出產的邊界導通模式L6561 IC製作兩段式昇壓功率因數修正器以降低高頻電流諧波並提高額定功率及電力品質，搭配SG公司出產的SG6841 IC和PI公司出產的TOP263 IC以返馳式架構製作主電源直流-直流轉換器和待機電源直流-直流轉換器，設計待機電源於待機功率小於1瓦，以降低待機時之功率損耗。另外直流-交流換流器採用O2 Micro公司出產的OZ9939 IC，並將此IC適用的推挽式架構轉換為全橋式架構搭配串並聯諧振電路以降低切換開關之溫度，提昇整體效能，並嘗試採用1顆變壓器驅動3隻燈管搭配平衡電感做燈管電流平衡控制。 最後將交流-直流轉換器和直流-交流換流器整合於一PCB板以節省板材損耗和空間，並搭配奇美20吋6燈管的液晶電視面板作量測及探討，其中電源供應器輸入電壓為90~264Vac，燈管電流為6mA，交流-直流轉換器效率最高為83%，直流-交流轉換器效率最高為86%，整體最高效率為71.5%。
並列摘要
This thesis presents the results of study and implement action to integrate two subsystems of (1) two-stage power factor correction ac-dc converter and (2) dc-ac inverter. To enhance the efficiency of low utlity-line and reduce the temperature of main components such as MOSFETs, ICs and transformers, the two-stage power factor correction subsystem bootsts up to 230 V on low utlity-line and 400 V on high utlity-line separats by a line reference voltage 150 V. This power factor correction subsystem reduces the total harmonic distortions of input current and enhances the rated power and efficiency by using the boundary-conduction-mode (BCM) operated L6561 IC of ST, this main power dc-dc converter and standby power dc-dc converter subsystem is both using the flyback topology, are used with SG6841 IC of SG and TOP 263 IC of TI. This thesis also covers the standby mode design with the resulting standby power being under 1 watt to reduce the power distortion of standby mode. The dc-ac inverter subsystem using the OZ9939 IC of O2 Micro, is the “push pull” instead of the “full bridge” topology to reduce the temperature of switches, and enhance the total efficiency. This thesis tries to use one transformer to control the lamp current equivalently with a balance choke. Then, the proposed circuit integrats the ac-dc converter and dc-ac inverter subsystems on the same PCB board for saving the materials and space, and it is tested with a 20-inches 6 lamps TV panel. According the experiment reveals the optimum efficiency of the ac-dc converter being at 83% during the voltages from 90 to 264, and the optimum efficiency of inverter is at 86% with lamp current of 6mA. The optimum total system efficiency of the integrated power supply is at 71.5%, with an above average performance.