臺灣博碩士論文加值系統

近年來，由於全球環保意識逐漸抬頭，白光LED具有體積小、發熱量低、壽命長、耗電量小、不含汞等眾多優點，已逐漸取代照相手機與數位相機的閃光燈、車用照明、非自發光液晶顯示器背光源。LED的亮度取決於順向導通電流，穩定的工作電流也有助於使用壽命，因此供給一個穩定的電源就是LED驅動電路的首要課題。
本論文實現一具自適應斜率補償高效率白光LED驅動器，使用TSMC 0.25μm CMOS High Voltage 60V高壓製程製作，可驅動2~12顆白光LED。電路採峰值電流回授(Peak Current mode)及脈波寬度調變(Pulse width modulation) 模式設計。切換頻率為1MHz，當WLED導通電壓3.9V，負載12顆時，輸出電壓為47V，輸出電流為20mA，並具過電流保護機制。本論文較特別處為使用自行設計的前緣遮罩(Leading Edge Blanking)電路，抑制前緣突波雜訊。改良式軟啟動電路，可將軟啟動電容設計於晶片內部，且所占的面積不大。以及自適應斜率補償器，可依輸入電壓與輸出電壓的不同，產生最佳的斜率補償。

In recent years, because the gradual rise of global environmental awareness, white light-emitting diodes (LEDs) with advantages of small sizes, less heat, long lives, low power consumption, and not containing mercury, have gradually replaced the flash of camera phone and digital camera, automotive lighting, and backlight of non-light-emitting liquid crystal display. The brightness of LED is dependent on the forward current. A stable forward current is helpful to the operation life. Therefore, how to supply stable power is becoming the most important topic of LED driving circuits.
This thesis presents a high efficiency boost white LED driver with adaptive slope compensation technique, which can drive 2~12 white light-emitting diodes and is implemented in TSMC 0.25μm CMOS High Voltage 60V process. The circuit is designed with peak current mode and pulse width modulation control. The switch frequency is 1MHz. When loading 12 WLEDs with turn on voltage of 3.9V, the output voltage is 47V and the output current is 20mA with over current protection. Using leading edge blanking which designed by myself to constrain spike noise is the special and unique part in this thesis. On-chip soft-start circuit occupies a small silicon area and eliminates the need of extra pin-out. Further more, according to different input voltages and output voltages, the adaptive slope compensation technique can result in the optimum slope compensation.

摘要 I
Abstract II
第一章 緒論 1
1.1 研究動機 1
1.2 論文架構 3
第二章 白光LED驅動架構 4
2.1 白光LED I-V特性曲線 4
2.2 白光LED驅動方法分析 5
2.2.1 定電壓驅動 5
2.2.2 定電流驅動 6
2.3 驅動多顆白光LED 8
2.3.1 並聯驅動 8
2.3.2 串聯驅動 9
2.4 直流驅動電路種類 9
2.5 升壓轉換驅動器架構 12
2.5.1 切換式電容升壓轉換器架構 12
2.5.2 切換式電感升壓轉換器架構 14
2.6 白光LED驅動器效率 16
第三章 切換式電感升壓轉換器操作原理分析 17
3.1 電感電流連續導通與非連續導通模式 17
3.1.1 連續導通模式 17
3.1.2 非連續導通模式 21
3.1.3 連續與非連續導通模式之邊界條件 25
3.2 控制模式 27
3.2.1 電壓模式 27
3.2.2 電流模式 29
3.3 調變模式 35
3.3.1 脈衝寬度調變模式 35
3.3.2 脈衝頻率調變模式 36
3.4 穩定度分析 38
第四章 LED驅動電路設計與實現 43
4.1 偏壓電路 44
4.2 誤差放大器 48
4.3 能隙參考電壓源 51
4.4 比較器 55
4.5 振盪和鋸齒波產生器 56
4.6 軟啟動電路 58
4.7 電流感測電路 60
4.8 前緣遮罩電路 61
4.9 自適應斜率補償器 62
4.10 電壓轉電流轉換器 64
4.11 SR正反器 67
4.12 脈衝寬度調變電路 68
4.13 控制電路 69
第五章 白光LED驅動器模擬結果與晶片佈局 71
5.1 晶片佈局 72
5.2 白光LED驅動器模擬結果 76
5.3 文獻比較 82
5.4 量測結果 83
第六章 總結與未來展望 85

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