本文主要針對可調光LED照明系統設計一個電源轉換器，採用兩級式設計，以邊界導通模式升壓型功因修正電路做為前級穩壓器，後級為準諧振返馳式轉換器來減少開關切換損失，提高轉換效率。 目前因為泛用電壓的要求導致在電源設計時，DC BUS電壓較高，這樣會使低電壓輸入時，前級PFC會產生較大的切換損失，所以本論文前級主動功因修正電路具有輸出電壓調節功能，在低電壓輸入時，會有較低的PFC輸出電壓，來減少前級的切換損失。當輸出功率需求下降時，主動式PFC的切換損失將導致輕載效率較差，所以本論文PFC在輕載時關閉PFC功能，使整體效率提升。後級採用具有電壓波谷切換特性的準諧振返馳式轉換器，可以有效降低切換損失及雜訊，同時保有返馳式轉換器拓樸架構簡單、低成本的優點。 本文並發展了一RGB LED混光電路作為LED驅動器負載，利用MCU透過SPI通訊協定，將調光資料傳送至RGB混光IC調整RGB LED亮度，以產生輕重載變化，來驗證本文LED驅動電路之設計。並藉由模擬軟體SIMetrix/SIMPLIS建構LED驅動IC模型，並進行電路行為模擬，以利電路分析。最後實做一台輸入功率100W具主動功因調節LED電源轉換器，其交流輸入範圍90Vac至264Vac，最高功因可達0.99，輕載效率可達88% 。 ;This thesis mainly designs a power supply converter for the dimmable LED lighting system. Based on the two-stage design, it takes boost power factor correction (PFC) circuit in boundary conduction mode as the front stage voltage stabilizer and quasi resonant flyback converter as the rear stage to reduce switching loss and improve conversion efficiency. At present, the requirement of universal voltage results in high DC bus voltage in the design of power supply, which makes the PFC generating more switching loss in low voltage input. Therefore, the active power factor correction circuit in the front stage developed in this thesis has the function of adjusting output voltage. That is to say, lower PFC output voltage in low voltage input can reduce the switching loss in the front stage. On the other hand, when the demand for output power decreases, the switching loss of the PFC will result in poor light load efficiency. Therefore, in this thesis, the PFC function is shut down when it is in light load to improve the overall efficiency. In addition, the rear stage adopts quasi resonant flyback converter featured in switching of voltage valley, which can reduce the switching loss and the noise effectively with the advantages of simple topology framework and low cost. This thesis also develops an RGB LED color-mixing circuit as the load of the LED drive. In order to verify the design of LED drive circuit with changing load, it utilizes a microcontroller to transmit dimming data to an RGB color-mixing IC through SPI communication to adjust the RGB LED luminance. Moreover, the simulation software SIMetrix / SIMPLIS is utilized to establish the IC model of LED drive and to simulate the circuit behavior for circuit analysis. Finally, an LED power supply converter with input power of 100W and active power factor adjustment is manufactured with AC input range 90Vac-264Vac, highest power factor 0.99, and light load efficiency 88%.
