本論文旨在應用適應性控制於LED驅動電路。有別於傳統LED驅動電路，本論文採用適應性電壓回授控制技術，可動態調整直流-直流轉換器之輸出電壓。其核心概念為透過最低電壓偵測器配合適應性電壓回授控制電路，改變轉換器當中誤差放大器之參考電壓VREF，藉此調整其輸出電壓且降低線性電流調節電路之功率消耗。

本論文以TSMC 0.35 μm 2P4M CMOS製程來實現，晶片面積為1.173×1.146 mm2，轉換器採用升壓型，操作頻率為100 kHz，最大負載電流為200 mA。量測結果顯示，適應性電壓回授控制電路將會有效地降低功率消耗。

The purpose of this thesis is to apply the adaptive control technique into LED drivers. To compare the conventional LED driver, we adopt adaptive voltage feedback control technique, which can dynamically adjust the output voltage of the dc-dc converter. Its main concept is to tune the error amplifier's reference voltage of dc-dc converter with the minimum voltage detector and adaptive voltage feedback controller. As a result, the output voltage of the dc-dc converter is adjusted to reduce the power consumption of linear current regulators.

The chip is implemented with TSMC 0.35 μm 2P4M CMOS process, and its size is 1.240×0.849 mm2. A boost converter is used, and the operating frequency and the maximum load current are 100 kHz and 200 mA, respectively. Experimental results show that the adaptive voltage feedback controller can effectively reduce the power dissipation on linear current regulator.

[1] K. H. Loo, W. K. Lun, S.-C. Tan, Y. M. Lai, and C. K. Tse, "On Driving Techniques for LEDs: Toward a Generalized Methodology," IEEE Trans. Power Electron., vol. 24, no. 12, pp. 2967–2976, Dec. 2009.
[2] K. H. Loo, Y. M. Lai, S. C. Tan, and C. K. Tse, "Stationary and Adaptive Color-shift Reduction Methods Based on The Bilevel Driving Technique for Phosphor-converted White LEDs," IEEE Trans. Power Electron., vol. 26, no. 7, pp. 1943–1953, Jul. 2011.
[3] A. I. Pressman, Switching Power Supply, 2nd ed., New York: McGraw-Hill, 1999.
[4] W. K. Lun, K. H. Loo, S. C. Tan, Y. M. Lai, and C. K. Tse, "Bilevel Current Driving Technique for LEDs," IEEE Trans. Power Electron., vol. 24, no. 12, pp. 2920–2932, Dec. 2009.
[5] H. J. Chiu, Y. K. Lo, J. T. Chen, S. J. Cheng, C. Y. Lin, and S. C. Mou, "A High-Efficiency Dimmable LED Driver for Low-Power Lighting Applications," IEEE Trans. Ind. Electron., vol. 57, no. 2, pp. 735–743, Feb. 2010.
[6] C. H. Wu and C. L. Chen, "High-Efficiency Current -Regulated Charge Pump for a White LED Driver," IEEE Trans. Circuits Syst. II, vol. 56, no 10, pp. 763–767, Oct. 2009.
[7] M. S. Lin and C. L. Chen, "An LED Driver with Pulse Current Driving Technique," IEEE Trans. Power Electronics, Vol. 27, No. 11, pp.4594-4601, Nov. 2012.
[8] H. Chen, Y. Zhang and D. Ma, "A SIMO Parallel-String Driver IC for Dimmable LED Backlighting with Local Bus Voltage Optimization and Single Time-Shared Regulation Loop," IEEE Trans. Power Electron., Vol. 27, No. 1, pp.452-462, Jan. 2012.
[9] S. I. Hong, J. W. Han, D. H. Kim, O. K. Kwon, "A Double-Loop Control LED Backlight Driver IC for Medium-Sized LCDs," in IEEE ISSCC Dig. Tech. Papers, 2010, pp. 116-118.
[10] C. S. Moo, Y. J. Chen and W. C. Yang, "An Efficient Driver for Dimmable LED Lighting," IEEE Trans. Power Electron., vol. 27, no. 11, pp. 4613-4618 , Nov 2012.
[11] 梁適安，交換式電源供應器之理論與實務設計，二版，全華圖書，2008。
[12] M. K. Kazimierczuk Pulse-Width Modulated DC-DC Power Converter, New York: Wiley. 2008.
[13] B. Razavi, “Design of Analog CMOS Integrated Circuits,” New York: McGraw-Hill, 2001.
[14] P. E. Allen, and D. R. Hoolberg, "CMOS Analog Circuit Design," New York: Oxford. 2002.
[15] C. F. Lee and P. K. T. Mok, "A Monolithic Current-Mode CMOS DC-DC Converter with On-Chip Current-Sensing Technique," IEEE J. Solid-State Circuit, vol. 39, no. 1, pp. 3-14, Jan. 2004.
[16] C. H. Lin, K. H. Chen, and H. W. Huang, "Low-dropout Regulators with Adaptive Reference Control and Dynamic Push–pull Techniques for Enhancing Transient Performance," IEEE Trans. Power Electron. vol. 24, no. 4, pp. 1016–1022, Apr. 2009.
[17] C. Y. Hsieh and 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 J. Solid-State Circuits, vol. 44, no. 9, pp. 2568-2580, Sep 2009.