應用於一次側控制準諧振返馳式轉換器之定電流輸出技術

Abstract

由於返馳式電源轉換器具有架構簡單、價格低廉等優點，因此廣泛地使用在低功率電子產品上。具谷底切換功能之準諧振返馳式轉換器相較於操作在連續導通模式或不連續導通模式具有更低的導通損失，故能提升效率及降低元件溫度。在本論文中，將詳細說明返馳式轉換器及準諧振返馳式轉換器的工作原理並提出一應用於一次側控制準諧振返馳式轉換器之定電流輸出技術。接著提出該技術中關鍵之輸出電流估計電路，透過模擬結果得知其電路之可行性。

Flyback converters have been widely used in low power applications due to simple structure and low cost. Quasi-resonant flyback converters with valley switching technique provide less turn-on losses compared with continuous-conduction mode and discontinuous-conduction mode, resulting in better efficiency and lower device temperature. In this thesis, we will illustrate the theory of the flyback converter and propose a constant current output technique applied to primary-side controlled quasi-resonant flyback converters. An output current estimator is presented, and simulation results have verified the feasibility of the proposed circuit.