本論文主要研製一具功率因數修正之半橋LLC諧振轉換器,傳統LLC諧振轉換器具有輕載效率較低的問題,此問題通常會採用Burst-mode來解決,但使用Burst-mode解決輕載效率較低的問題會有輸出漣波大、噪音、動態響應差等問題,所以本論文使用諧振電容控制來達到輕載效率改善的效果;此外,此控制方法也可用於延長維持時間。最後,本論文實作出一台300W之AC/DC電源供應器,其輸入電壓為90 ~ 264 Vac,輸出電壓50 Vdc,滿載輸出電流6 A,整體平均功因達0.94以上,平均效率可達90%,最高效率達93%,相關實驗結果驗證所設計之具功率因數修正之諧振電容控制之半橋LLC諧振轉換器具有改善輕載效率及延長維持時間之效果。;This thesis focuses on the design and implementation of a half-bridge LLC resonant converter with power factor correction. The traditional LLC resonant converter suffer from the problem of poor light-load efficiency. Burst-mode is usually used to solve this problem, but Burst-mode has problems like large output voltage ripple, acoustic noise, poor dynamic response. This thesis proposes a resonant capacitor controlled LLC resonant converter to improve light-load efficiency. In addition, this control method can be used to extend hold-up time. Finally, this thesis implements a 300W AC/DC power supply. The input voltage range is 90 ~ 264V_ac, the output voltage is 50V_dc, and the output current is 6 A at full-load. The overall average power factor is more than 0.94. The average efficiency is 90%, and the highest efficiency is 93%. Finally, the relevant experimental results verify that the designed resonant capacitor controlled half-bridge LLC resonant converter with power factor correction has the effect of improving light load efficiency and extending the hold-up time.