以DSP為基礎之具低均流誤差之LED電流平衡驅動器

DSP-Based LED Current Balancing Driver with Low Error in Current Sharing

洪明傑(Ming-Jie Hong)

指導教授 ： 胡國英

國立臺北科技大學/電資學院/電力電子產業研發碩士專班/碩士(2011年)

摘要

本論文係提出一結合Zeta型轉換器及電流平衡電路之LED驅動器，此架構前端為一Zeta轉換器，於不同輸入電壓下可提供升壓/降壓輸出，本論文將採用降壓輸出，後端則採用LED電流平衡驅動電路，並同時提供一去磁路徑，其方法係藉由Zeta轉換器之能量傳遞電容來完成差動變壓器之去磁，以提升均流效果同時兼具能量回收，有別於傳統電流平衡電路採用稽納二極體或電阻消耗能量以完成去磁。就設計LED模組而言，本論文將設計出一個最佳LED串並聯數目，以降低電源設計的複雜度和成本。就數位控制而言，本論文將採用意法半導體公司所生產之數位信號處理器STM32F103VBT6 (ARM 32-bit Cortex™-M3 CPU)來作為數位控制器之核心，此微處理器同時兼具低耗電、低成本、高效能等優點。最後，藉由模擬來驗證所提架構之可行性，並以實驗波形來驗證所提架構之有效性。

關鍵字

Zeta型轉換器 ； 電流平衡電路 ； LED模組 ； 微處理器

並列摘要

In this thesis, a LED current balancing driver is presented, which combines one Zeta converter and one current balancing circuit. Hence, the frond-end stage is the Zeta converter, which provides a step-down voltage conversion in this application, whereas the following stage is the current balancing circuit mainly constructed by several differential transformers. Above all, the Zeta converter provides not only energy for the LED string but also the path for the differential transformer during the demagnetization period, so as to improve the performance of current balancing. By doing so, unlike the traditional current balancing circuit dissipating the demagnetizing energy in the zener diode or the resistor, the demagnetizing energy is sent back to the energy-transferring capacitor of the Zeta converter. In the design of the LED module, the optimal number of LEDs per LED string and the optimal number of LED strings will be carried out, so as to reduce the complexity and cost of the proposed LED driver. For the digital control to be considered, the digital signal processor (DSP) named STM32F103VBT6 (ARM 32-bit Cortex™-M3 CPU) is used as a controller kernel, which possesses low power dissipation, low cost, high performance, etc. Finally, some simulation results are given to verify the feasibility of the proposed topology, and some experimental results are offered to demonstrate its effectiveness.

並列關鍵字

Zeta Converter ； Current Balancing Circuit ； LED Module ； Microprocessor

參考文獻

[48] 賈證主，VHDL數位系統設計與應用，台北：台科大圖書股份有限公司，2004。

[2] Xiaohui Qu, Siu Chung Wong and C. K. Tse, “Color control system for RGB LED light sources using junction temperature measurement,” IEEE IECON’07, pp. 1363-1368, 2007.

[3] J.-P. M. G. Linnartz, L. Feri, Hongming Yang, S. B. Colak and T. C. W. Schenk “Communications and Sensing of Illumination contributions in a power LED lighting system,” IEEE ICC’08, pp. 5396-5400, 2008.

[4] Yuequan Hu and M. M. Jovanovic, “A novel LED driver with adaptive drive voltage,” IEEE APEC’08, pp. 565-571, 2008.

[5] Heinz van der Broeck, Georg Sauerlander and Matthias Wendt, “Power driver topologies and control schemes for LEDs,” IEEE APEC’07, pp. 1319-1327, 2007.