南台科技大学-mipaper.pdf

南台科技大學 電機工程研究所 碩士學位論文 以FPGA 為基礎之 RGB LED調光控制 Design and Implementation of FPGA-Based RGB LED Dimming Control 研 究 生：孫仲元 指導教授：朱慶隆 中華民國九十七年七月 II 摘 要 本文提出一種用於液晶顯示器之 RGB LED 背光板調光電路，使用 FPGA-EPM1270T144 來實現三色 RGB LED背光板之數位調光回授控制。使用數 位電路設計出 RGB LED 多段調光回授系統以及RS-232遠端控制，使用數位導通 週期調光方式來達到 RGB 光源混色的效果，並提出三種架構來做RGB LED調光 電路。由於 LED在長時間使用下，其元件隨溫度的變化會影響亮度和色溫穩定性。 本文提出利用色彩感測器作光學回授，利用色彩感測器產生的回授電壓，經由模 糊控制器作回授控制，控制 RGB LED 背光板在長時間使用下所產生的色飄移現 象。最後經由實驗證明開迴路控制 RGB LED的顏色，以閉迴路控制穩定度的效果。 關鍵字： RGB LED 、FPGA 、數位調光 IV ABSTRACT This thesis presents the implement and design of FPGA based RGB LED backlight digital control, including dimming control, feedback control and RS-232 baseband control. By using the digital PWM duty cycle to dim the illumination, we can achieve the RGB mixing light source with unique features such as instant color variability, and proposing three kind of RGB LED dimming control circuit. Under the long time use of LED, its part can affect brightness and stability of the color temperature along with the temperature change. The proposed article makes optics feedback on using the photo sensor element, fuzzy controller stabilizing the color of RGB LED backlight color drift phenomenon which under a long usage, produces the feedback voltage of photo sensor element. Finally, through the experiment, it can be demonstrated that the open loop controls RGB LED the color, and closed loop control stabilizes the RGB LED color temperature. Key Words ：RGB LED 、FPGA 、Digital dimming control