本文基於電壓源串接電流源之概念，提出一個高效率可調光之發光二極體(Light Emitting Diode, LED)驅動電路。驅動電路中的電壓源提供LED所需的切入電壓，由電流源調節LED發光所需的電流，其中，大部分功率由電壓源直接供應，作為電流源的功率轉換電路僅處理小部分LED所需的能量，因此可達成整體電路的高效率。此電路可利用電流源線性調節、脈波寬度調變(Pulse-Width Modulation, PWM)，以及雙脈波寬度調變(Double Pulse-Width Modulation, DPWM)三種方式調節LED電流來達到調光的目的。
本研究內容包括電路操作原理分析與設計方程式推導，並設計一實驗電路，驅動四十顆串聯之1 W高亮度白光LED，比較三種調光方式對白光LED色彩偏移之情況、發光效率及電路效率。實驗結果顯示，白光LED以線性調光的之色度偏移最為嚴重，DPWM調光之偏移程度最少；發光效率則以線性調光最高， DPWM調光最差；當輸入電壓為交流110 V，三種調光方式於額定輸出時，效率均可以達到95.5 %；當調光至10 %額定功率時，效率仍高於90.5 %。

A high efficiency driver circuit is proposed for Light Emitting Diode (LED) lamps with dimming feature. The current regulation is accomplished by processing partial power of the power conversion circuit so that a high overall efficiency can be realized. The detailed description and analysis of circuit operation are provided. The dimming feature can be accomplished by means of linear current regulation, pulse-width modulation (PWM) or double pulse-width modulation (DPWM).
Based on the circuit analyses and derived equations, a laboratory circuit is designed for an LED lamp which is composed of 40 high-brightness white LEDs in series. The performances with three dimming schemes are compared from the measured results. LEDs dimmed by DPWM have less color shift than those dimmed by linear current regulation and PWM. On the other hand, the dimming scheme with linear current regulation has the highest light efficiency over the entire dimming range. The circuit efficiency can be as high as 95.5% at the rated output and deteriorates slightly to 90.5% as the lamp is dimmed to 10% of the rated power.

目錄
中文摘要.......................................................................................................................I
英文摘要.....................................................................................................................Ⅱ
目錄.............................................................................................................................Ⅲ
圖目錄.........................................................................................................................Ⅴ
表目錄......................................................................................................................VIII
第一章 緒論 1
1-1 研究背景與動機 1
1-2 論文大綱................................... 3
第二章 白光LED介紹與實驗量測系統 4
2-1 白光LED 4
2-2 基礎色彩工程 6
2-3 實驗量測系統 10
2-4 白光LED光學及電器特性量測 11
第三章 驅動電路架構分析 16
3-1 LED驅動電路架構 16
3-2 工作模式 17
3-3 LED調光機制 20
3-3-1 線性電流調光 20
3-3-2 脈波寬度調變調光 21
3-3-3 雙脈波寬度調變調光 23
3-4 電路分析與參數設計 25
3-5 設計步驟 30
第四章 LED驅動電路設計與量測分析 32
4-1 電路參數設計 32
4-2 電路波形量測 34
4-3 調光時之波形量測 35
4-4 調光控制對白光LED色度之影響 43
4-5 調光控制對白光LED發光效率之影響 48
4-6 效率比較 50
第五章 結論與未來研究方向 53
5-1 結論 53
5-2 未來研究方向 54
參考文獻 55

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