本論文提出兩種應用於一般照明之可調光LED驅動器架構，第一種為耦合電感SEPIC功率因數修正器，搭配簡單的商用邊界模式控制器，在全範圍輸入電壓操作條件下達成高效率與高功率因數特性；該LED驅動器並具備適應性回授控制功能，利用改良式PWM調光技術調節LED電流及亮度。
第二種LED驅動器架構係採用連續導通模式之SEPIC功率因數修正器，以達到高功率因數、高效率和LED電流的調整。本論文詳細分析探討SEPIC功率因數修正器之操作原理和設計考量，並討論與比較數種均流方法，以調節並聯LED串的電流與亮度，滿足均流與亮度平衡的要求，且可有效降低電流漣波。除此之外，本架構加入旁路二極體設計，當LED損壞時，得以提供替代電流路徑以避免LED熄滅，藉以提升LED照明系統的可靠度。
本論文詳細分析討論電路之動作原理與設計考量，並實現一雛型電路驗證此架構的與控制策略之可行性。

The dissertation proposes two dimmable LED driver circuits for general lighting applications. The first driver circuit is a coupled inductor SEPIC power factor correction (PFC) converter with a simple commercial transition mode (TM) PFC controller. Under universal input voltage operation, high efficiency and high power factor can be achieved by using an adaptive feedback control. An improved pulse-width modulation dimming technique is studied for regulating the LED current and brightness.
The second LED driver uses a continuous current conduction mode (CCM) SEPIC PFC converter to achieve high power factor, high efficiency and LED current regulation. The operation principles and design consideration of the studied CCM SEPIC PFC are analyzed and discussed in detail. To regulate the LED current and brightness, some current sharing methods are studied and compared. The requirements for the current sharing and luminance balance among paralleled LED arrays can be satisfied while current ripple is eliminated significantly. Because of the addition of bypass diodes, an alternative current path can be offered when a single LED fails. The LED array will not distinguish. Reliability of the LED lighting system can thus be improved effectively.
The operation principles and design considerations of the studied LED driver are analyzed and discussed. A laboratory prototype is also designed and tested to verify the feasibility.

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