在傳統交換式電源轉換器中，返馳式轉換器由於具有電路架構簡單、使用元件較少和成本低之特性，所以廣泛地使用在中低功率電子產品上。本論文透過計算及耗損分析發現，功率損耗大部分集中在二次側二極體整流器以及初級側功率開關上，因此，本論文利用同步整流技術，將二次側的輸出二極體置換成導通電阻極低之同步整流開關，可有效的降低功率損耗，提升整體效率。
最後本論文結合理論分析並提供步驟性的電路設計流程，藉由模擬軟體SIMetrix/SIMPLIS建置高擬真電源IC模組，進行電路模擬且提供各項效率改善方案與分析，利於使用者了解並設計本文電路架構，縮短系統設計時間；最後實作一65W具同步整流之返馳式電源轉換器，其交流輸入電壓範圍90V至230V，分別測量二次側是否有使用同步整流之技術，進行效率比對，由實驗結果可得知有使用同步整流效率可多提升2%，其效率可達88%。

In the conventional switching power converters, the flyback converter widely used in medium and low power electronics because of simple circuit structure, less use of components and low cost. This thesis discussed that power losses are concentrated on the diode rectifier in the secondary side. The power switch in the primary side through the calculation and consumption analysis. The thesis proposed the output diode in the secondary side was replaced by the synchronous rectifier switch with low conduction resistance by using synchronous rectification technology. This method can effectively reduce power consumption and improve overall efficiency.
Finally, this thesis combines the implementation and the theoretical analysis and provides step by step designing procedures of electrical circuit by the simulation software, SIMetrix/SIMPLIS that establishes a highly realistic power IC module. It offers the circuit simulation, the plan of improving efficiency and the system analysis. In other words, it helps users to comprehend this thesis about electrical circuit structures and designs. It will shorten the time of system designing. This thesis implemented with Flyback Converter with 65W and synchronous rectification, which has wide AC input voltage range between 110V to 230V. The secondary side with synchronous rectification technology and without synchronous rectification technology was measured repectively for efficiency comparison. The experimental results show that the use of synchronous rectification can improve 2% of the efficiency and the efficiency, reach the high efficiency around 88%.

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