在這個能源短缺與現代人對環保意識的提高，人們越加注意到節能的迫切與重要性，根據國際能源總署(Internal Energy Agency,IEA)指出，近年來全球照明設備的電耗幾乎占了全球電量產值得20%，如何有效的節能，是目前科技研究要實現的目標，也是眾所關心的議題。在過去的一百多年裡，作為人類文明象徵的照明技術有了飛快的發展。作為照明技術的主體光源歷經了三個重要的發展階段：白熾燈、螢光燈、HID(High Intensity Discharge)燈。而現在，發光二極管LED(Light Emitting Diode)已儼然成為照明光源的主流。LED具有壽命長、體積小、發光效率高的優點，但由於LED的亮度取決於順向導通電流，因此供應一個恆定電流為LED驅動電路首要之課題。
本研究以DC-DC升壓轉換器為架構，設計一驅動IC來控制負載的輸出電壓。本驅動IC具切換PWM(Pulse Width Modulation)/PFM(Pulse Frequency Modulation)的自動控制功能，因重載時PWM效率較高、PFM低；輕載時PFM效率高、PWM低，所以本設計在切換輕重載時，PWM/PFM模式也隨之切換，已達到良好的轉換效率。電路中包含了抗溫度飄移電路，輸出參考電壓在-25~125℃時之溫度係數為15.79ppm/℃，藉此參考電壓可以在驅動LED時較不受IC環境溫度的變化而影響LED工作電流改變。此IC電路的功率電晶體下放了一顆限流電阻，防止PFM一開始的Duty太大而導致輸入電流過大燒毀IC。
本研究之LED驅動IC，電源電壓為1.8V，輸入電壓為1.7V，輸出電壓10V，能量轉換效率87.1%。而驅動LED最大電流為20mA，供應多串LED負載，電路使用TSMC 0.18 UM CMOS Mixed Signal RF General Purpose MiM 1P6M 1.8V&3.3V製程實現，晶片面積為1.4071×0.8276mm^2。

In this energy shortage and the rising awareness of environmental protection, people pay more attention to the urgency and important of energy conservation. According to the International Energy Agnecy (IEA) noted,the electricity consumption of global lighting equipment accounts for almost 20% of global electricity output in recent years. Hence, how to save energy from lighting equipment has become a big issue to the public. In the past 100 years, as a symbol of human civilization, lighting technology has developed rapidly. The main lighting technology has gone through three important stages: Incandescent, fluorescent, HID. Now, LED (Light Emitting Diode) has become the mainstream of the lighting source. The advantage of LED contains long life, small size, and high luminous effocency. Cause of the luminance of LED depends on the forward current, it’s the primary subject which supply a constant current to LED.
In this research, based on the DC-DC boost converter, design an IC driver to control the output voltage and supply a constant current to LED. The IC consists of PWM (Pulse Width Modulation) / PFM (Pulse Frequency Modulation) mode. In the heavy load, system switch on PWM mode；in the light load, system switch on PFM mode cause PWM has better efficiency in heavy load, PFM has better efficiency in light load. The circuit contains low temperature drift ciruit which temperature coefficient is 15.79ppm/℃ between -25~125 ℃. The power transistor of this circuit has a current limiting resistor the prevent IC from burning down due to the beginning duty of PFM too much to cause the big current.
In this work, the power supply voltage is 1.8V, the input voltage is 1.7V, the output voltage is 10V, the energy conversion efficiency is 87.1%. And drive the maximum current of 20mA to LED, and can supply the multi-string LED load. The IC is realized by using TSMC 0.18 UM CMOS Mixed Signal RF General Purpose MiM 1P6M 1.8V & 3.3V. The chip area is 1.4071 × 0.8276mm^2.

目錄
論文審定書 i
論文公開授權書 ii
誌謝 iii
目錄 vii
圖次 x
表次 xiii
第一章 緒論 1
1.1研究背景 1
1.2 研究動機 2
1.3 LED驅動IC發展 3
第二章 LED元件特性與研究理論 12
2.1 LED元件特性 12
2.1.1 LED基本結構 12
2.1.2 LED發光原理 13
2.1.3 LED常用半導體材料與種類 14
2.1.4 LED參數特性 16
2.2 LED DC-DC升壓轉換器 17
2.3 LED 控制器系統 21
2.3.1 PWM系統 21
2.3.2 PFM系統 22
第三章 電路設計架構 25
3.1 整體架構簡介 25
3.1.1 PWM ( Pulse Width Modulation ) 25
3.1.2 PFM ( Pulse Frequency Modulation ) 25
3.1.3 限流電阻( Limit ) 25
3.1.4 閘極驅動器( DRV ) 25
3.1.5 參考電壓( TPC ) 26
3.2 基礎電路介紹 27
3.2.1 抗溫度飄移電路 ( Temperature Compensation Circuit ) 27
3.2.2 比較器( Comparator ) 28
3.2.3 壓控環形振盪器( VCO )與三角波產生器( Tri ) 30
3.2.4 誤差放大器( EA ) 32
3.2.5 多工器( MUX ) 33
3.2.6 除頻器( DFF ) 34
3.2.7 SR正反器( SR Latch ) 35
3.2.8 Gate Driver( DRV ) 36
3.3 迴路穩定性 37
3.4 PWM系統 39
3.5 PFM系統 40
3.6 切換PWM/PFM機制 41
3.7 設計流程 42
第四章 模擬結果與討論 43
4.1 基礎電路 43
4.1.1 抗溫度飄移電路( TPC ) 43
4.1.2 三角波產生器電路( Tri ) 46
4.1.3 除頻器( DFF ) 49
4.2 PWM系統 50
4.3 PFM系統 51
4.4 整體架構輸出波形 53
4.5 佈局平面圖 61
4.6 預計規格和效能比較表 62
第五章 結果討論與未來展望 64
5.1 結果討論 64
5.2 未來展望 65
參考文獻 66

圖次
圖2-1 LED芯片的基本結構 12
圖2-2 LED等效電路圖 13
圖2-3 LED發光原理示意圖 14
圖2-4 LED I-V曲線 16
圖2-5 DC-DC升壓轉換器 17
圖2-6(a) 17
圖2-6(b) 18
圖2-7 Boost 升壓過程 18
圖2-8(a) 連續導通模式 19
圖2-8(b) 不連續導通模式 19
圖2-9 典型DC-DC 電感升壓轉換器架構 20
圖2-10 PWM典型架構 21
圖2-11 PWM輸入輸出波形 22
圖2-12 PFM典型架構 23
圖2-13 PFM時序圖 24
圖3-1 整體架構圖 26
圖3-2 溫度補償之參考電壓電路 28
圖3-3 比較器電路圖 30
圖3-4 壓控環形振盪器 30
圖3-5振盪器單級電路圖 31
圖3-6 三角波產生器電路圖 32
圖3-7 誤差放大器電路圖 33
圖3-8 多工器電路圖 34
圖3-9 D filp flop電路圖 35
圖3-10 除頻器電路圖 35
圖3-11 SR Latch電路圖 36
圖3-12 Gate Driver電路圖 37
圖3-13 誤差放大器補償電路圖 38
圖3-14 不穩定系統(a)和穩定系統(b)之簡易波德圖 39
圖3-15 PWM架構圖 39
圖3-16 PFM架構圖 40
圖3-17 切換PWM/PFM機制圖 41
圖3-18 設計流程圖 42
圖4-1 Pre-simulation of ref 43
圖4-2 Post-simulation of ref 44
圖4-3 Pre-simulation in -25℃~125℃ of ref 45
圖4-4 Post-simulation in -25℃~125℃ of ref 45
圖4-5 Pre-simulation of triangular 703KHz 46
圖4-6 Post-simulation of triangular in 703KHz 47
圖4-7 Pre-simulation of triangular 252KHz 47
圖4-8 Post-simulation of triangular 252KHz 48
圖4-9 Pre-simulation of DFF 49
圖4-10 Post-simulation of DFF 50
圖4-11 Pre-simulation of PWM 51
圖4-12 Post-simulation of PWM 51
圖4-13 Pre-simulation of PFM 52
圖4-13 Post-simulation of PFM 53
圖4-14 Pre-simulation of Vout、Iout、in PWM system 54
圖4-15 Post-simulation of Vout、Iout、in PWM system 55
圖4-16 Micro wave of Vg ( PWM ) 55
圖4-17 Pre-simulation of Vout、Iout、in PFM system 56
圖4-18 Post-simulation of Vout、Iout、in PFM system 57
圖4-19 Micro wave of Vg ( PFM ) 57
圖4-20 (a)無限流電阻下輸入電流 (b)有限流電阻下輸入電流 58
圖4-21 Pre-simulation of Vout at 3 corner ( PWM ) 59
圖4-22 Pre-simulation of Vout at 3 corner ( PFM ) 60
圖4-23 整體Layout圖 61

表次
表1-1 聚積LED驅動IC發展 3
表1-2 普誠LED驅動IC發展 4
表1-3 聚積LED驅動IC發展 5
表1.4 聚積LED驅動IC發展 6
表1-5 聚積LED驅動IC發展 7
表1-6 聚積LED驅動IC發展 8
表1-7 立錡LED驅動IC發展 9
表1-8 LED驅動IC參考文獻 10
表1-9 LED驅動IC參考文獻 11
表2-1 常用半導體材料 15
表3-1 多工器真值表 33
表3-2 D filp flop真值表 34
表3-3 SR Latch真值表 36
表4-1 各個負載在PWM/PFM模式下的效率表 54
表4-2 3個corner在重載下Vout的對照表 59
表4-3 3個corner在輕載下Vout的對照表 60
表4-4 預計與Pre-simulation、Post-simulation規格表 62
表4-5 規格比較表 63

參考文獻
[1] J. M. Jorge, C. R. B. S. Rodrigues, G. M. Soares, D. P Pinto, H. A. C. Braga, “A novel method of current equalization in LED strings based on simple linear circuit, ” 2011 IEEE International Symposium on Industrial Electronic, pp.95-100, Jun. 2011.
[2] C. Wang, J. Xi, L. He, “A linear constant current LED driver with no off-chip inductor or capacitor, ” 2014 IEEE 23rd International Symposium on Industrial Electronics (ISIE), pp.2524-2528, Jun. 2014.
[3] Y. Hsieh, K. H. Chen, “Boost DC-DC converter with fast reference tracking (FRT) and charge-recycling (CR) techniques for high-efficiency and low-cost LED driver, ” IEEE Journal of Solid-State Circuits, vol. 44, no. 9, pp.2568-2580, Sep. 2009.
[4] B. M. Lim, Y. H. Ko, Y. S. Jang, O. H. Kwon, S. K. Han, S. G. Lee, “A 200-V 98.16%-efficiency buck LED driver using integrated current control to improve current accuracy for large-scale single-string LED backlighting applications, ” IEEE Transactions on Power Electronics, vol. 31, no. 9, pp. 6416-6427, Nov. 2015.
[5] 聚積科技取自網頁資料: http://www.mblock.com.tw/tw/index.php
[6] 普誠科技取自網頁資料: http://www.princeton.com.tw/en-us/home.aspx
[7] 立錡科技取自網頁資料: http://www.richtek.com/zh-TW/About Richtek
[8] 李濤峰(茂力科技股份有限公司)，“電流控制電路和電流控制方法”，中華民國專利編號I494732，2015年8月1日。
[9] 王世宇、蔡輝騰、籃茂峰、李天寶(恆耀電子股份有限公司)，“可調節功耗之LED驅動器及利用該驅動器之LED照明裝置”中華民國專利編號I514922，2015年12月21日。
[10] 戴志平、譚宏、賴向東編著，2011，LED照明驅動電路設計方法與實例，中國電力出版社。
[11] Steve Winder著，2010，高功率LED驅動電路設計與應用，五南圖書出版公司。
[12] Steve Winder著，2009，LED驅動電路設計，人民郵電出版社。
[13] 劉博文編著，2007，光電元件導論(第二版)，全威圖書。
[14] T. Kishi, H. Tanaka, Y. Umeda, O. Takyu, “A high-speed LED driver that sweeps out the remaining carriers for visible light communications,” IEEE Journal of Lightwave Technology, vol. 32, no. 2, pp. 239-249, Nov. 2013.。
[15] N. M. Mapula, W. R. Liou, “Integrated multi-channel constant current LED driver with PWM boost converter design in 0.35µm process, ” TENCON 2012 - IEEE Region 10 Conference, pp.1-6, Nov. 2012.
[16] C. L. Chen, W. L. Hsieh, W. J. Lai, “A New PWM/PFM Control Technique for Improving Efficiency Over Wide Load Range,” Electronics, Circuits and Systems, 17. Nov. 2008.
[17] B. Bose, “Pulse width modulation for electronic power conversion,” Wiley-IEEE Press, pp.138-208.
[18] M. T. Chung, C. L. Lee, C. Yin, C. C. Hsieh, “A 0.5 V PWM CMOS Imager With 82 dB Dynamic Range and 0.055% Fixed-Pattern-Noise,” IEEE Journal of Solid-State Circuits, vol. 48, no. 10, pp. 2522-2530, Aug. 2013.
[19] E. Gutierrez, L. Hernandez and F. Cardes, "A Pulse Frequency Modulation Interpretation of VCOs Enabling VCO-ADC Architectures With Extended Noise Shaping," IEEE Circuits and Systems Society, vol. PP, no. 99, pp. 1-14, 24. August. 2017.
[20] M. Abdulqader, A. Mohammand, M. Baker, “ A Multi-Input, Multi-Output Power Management Unit Using Dickson Charge Pump for Energy Harvesting Application,” Circuits and Systems (MWSCAS), 2016 IEEE 59th International Midwest Symposium on, pp. 16-19, 06. March, 2017.
[21] R. C. H. Chang, H. M. Chen, C. H. Chia, “ An Exact Current-Mode PFM Boost
Converter With Dynamic Stored Energy Technique,” IEEE Transactions on Power Electronics, vol. 24, no. 4, pp. 1129-1134, 13. Feb. 2009.
[22] W. R. Liou, P. H. Chen, J. C. Tzeng, “ A Synchronous Boost Regulator with PWM/PFM Mode Operation,” ASIC, 2009. ASICON '09. IEEE 8th International Conference, 11. Dec. 2009.
[23] S.S. Prasad, and P. Mandal, “A CMOS beta multiplier voltage reference with improved temperature performance and silicon tenability,” 17th International Conference onIEEE, VLSI Design, pp. 551-556, 2004.
[24] M.K. Adimulam, and K.K. Movva, “A low power CMOS current mode bandgap reference circuit with low temperature coefficient of output voltage,” Asia Pacific Conference on Postgraduate Research in Microelectronics and Electronic, pp. 144-149, Dec.2012.
[25] R. Dehghani, and S.M. Atarodi, “A new low voltage precision CMOS current reference with no external components,” IEEE Transactions on Circuitsand Systems II: Analog and Digital Signal Processing, vol. 50, no. 12, pp. 928-932, Dec. 2003.
[26] G. Kapur, C.M. Markan, and V.P. Pyara, “On-chip tunable wide ranged multiple output voltage reference,”IEEE, Southeaston, pp. 1-4, Mar. 2012.
[27] T -C. Lu, H.-W. Zan, and M.-D. Ker, “Temperature coefficient of poly-Silicon TFT and its application on voltage reference circuit with temperature compensation in 80 LTPS process,” IEEE Transaction on Electron Devices, vol. 55, no. 10, pp. 2583-2589, Oct. 2008.
[28] S. Liu, and R.J. Baker, ”Process and temperature performance of a CMOS beta-multiplier voltage reference,” Midwest Symposium on IEEE, Circuits and Systems, pp. 33-36, Aug. 1998.
[29] B. Razavi, “Design of analog CMOS integrated circuits,” Boston: McGraw-Hill,2000.
[30] N. LaflammeMayer, O. Valorge, Y. Blaquiere, and M. Sawan, “A low-power, small-area voltage reference array for a wafer-scale prototyping platform,” 8th IEEE International, NEWCAS Conference, pp. 189-192, Jun. 2010.
[31] Y.-Y. Chen, S.-A. Zhong, and H. Dang, “Design of Bandgap Current Reference with Wide Range of Output Voltage in a 0.18μmBi-CMOS Process,” WRI World Congress on IEEE, Computer Science and Information Engineeringg, pp. 384-386, Apr. 2009.
[32] E. Abiri, M. R. Salehi, S. Mohammadalinejadi, “A low dropout regulator with enhanced transconductance error amplifier and small output voltage variations,” Electrical Engineering (ICEE), 2013 21st Iranian Conference, pp14-16, 16. Sep. 2013
[33] J. Roh, “ High-performance error amplifier for fast transient DC-DC converter,” IEEE Transactions on Circuits and Systems, vol. 52, no. 9, pp.591-595, 19. Sep. 2005.
[34] P. J. Liu, T. H. Chen, S. R. Hsu, “ Area-efficient error with current-boosting module for fast-transient buck converter,” IET Power Electronics, vol. 9, no. 10, pp. 2147-2153, 18. Aug. 2016.
[35] TEXAS INSTRUMENTS, 編號AN-1286, “Compensation for the LM3478 Boost Controller,” SNVA067C-December 2003-Revised April. 2013.
[36] H. M. Chen, D. D. Jiang, R. C. Chang, “A Monolithic Boost Converter with an Adaptable Current-Limited PFM Scheme, ” Circuits and Systems, 2006. APCCAS 2006. IEEE Asia Pacific Conference, pp. 4-7, 10. Apr. 2007.
[37] R. Jacob Baker, “CMOS: Circuit Design, Layout, and Simulation, ” WILEY, 2010.
[38] F. Wu, H. Deng, Y. Yin, “A high PSRR bandgap reference for LED driver, ” Information Technology, Networking, Electronic and Automation Control Conference, IEEE, pp. 20-22, 05. Sep. 2016.
[39] L. Wang, C. Zhan, S. Zhao, “Design of high-PSRR current-mode bandgap reference with improved frequency compensation, ” Electron Devices and Solid-State Circuits (EDSSC), 2016 IEEE International Conference, pp. 3-5, 19. Dec. 2016.
[40] S. W. Lee, H. L. Do, “ Boost-Integrated Two-Switch Forward AC–DC LED Driver With High Power Factor and Ripple-Free Output Inductor Current, ” IEEE Transactions on Industrial Electronics, vol. 64, no. 7, pp. 5789-5796, 16. Jan. 2017.
[41] Y. Gao, L. Li, P. K. T. Mok, “ An AC-input inductorless LED driver for visible-light-communication applications with 8Mb/s data-rate and 6.4% low-frequency flicker, ” Solid-State Circuits Conference (ISSCC), 2017 IEEE International, pp. 5-9, 06. Mar. 2017.
[42] Y. T. Hsieh, B. Da. Liu, J. F. Wu, C. L. Fang, H. H. Tsai, Y. Z. Juang, “A high current accuracy boost white LED driver based on offset calibration technique, ” IEEE Transactions on Circuits and Systems II: Express Briefs, vol. 58, no. 4, pp.244-248, Apr. 2011.
[43] M.Uno, K. Sugiyama, “PWM- and PFM-controlled switched capacitor converter-based multiport converter integrating voltage equalizer for photovoltaic systems,” Future Energy Electronics Conference and ECCE Asia (IFEEC 2017 - ECCE Asia), 2017 IEEE 3rd International, pp.3-7, 27. July. 2017.