利用線性調光方法進行LED驅動器特性分析與架構比較
No Thumbnail Available
Date
2014
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
本文提供在線性調光下直流電壓輸入輸出的變動對於高亮度LED電流精準度、頻率與亮度影響之分析，作為架構設計之依據。在調光的方法中脈波寬度調變調光(PWM Dimming)最廣泛的被使用，但是在調光至低亮度時會看見LED的閃爍現象。另外，線性調光方法可以有更大的調光範圍而不會在低亮度時閃爍，但是在調光至低亮度線性調光會產生色溫現象。
從實驗及理論的結果進行分析顯示峰值電流控制(Peak Current Control，PCC)的LED驅動器雖然電路較為簡單，但是驅動電路的線性調光範圍較小，且對應輸入電壓與輸出電壓變化的電流控制能力較差，輸入或輸出電壓改變下LED亮度和電流也會一起改變。遲滯電流控制(Hysteretic Current Control，HCC)架構的LED驅動器和峰值電流控制比較線性調光範圍更大，在LED調節至較低亮度時調光較穩定，同時它對於輸入電壓與輸出電壓變化時LED的電流控制能力較峰值電流控制好，所以LED的亮度幾乎不會隨輸入電壓與輸出電壓變化而變動，但是在輸入輸出的電壓變化下電路的動作頻率也會跟著改變。本文將LED驅動電路的實驗結果分析給設計者參考數據比較各類型驅動器。
This thesis studies the characteristics of LED linear dimming using Peak Current Control (PCC) and Hysteretic Current Control (HCC) methods. It provides the results of the luminosity control capabilities of LEDs and the effects of LED luminosity by changing the input/output DC voltage. According to the results of the experiments and theories, the circuit for LED driver for Peak Current Control (PCC) is simpler, but the range of its linear dimming is smaller. Additionally, the capability of LED current control with PCC is worse compared to HCC. The range of linear dimming is wider for the LED driver using Hysteretic Current Control (HCC). Moreover, its capability of LED current control for the change of input and output voltage is better than PCC.
This thesis studies the characteristics of LED linear dimming using Peak Current Control (PCC) and Hysteretic Current Control (HCC) methods. It provides the results of the luminosity control capabilities of LEDs and the effects of LED luminosity by changing the input/output DC voltage. According to the results of the experiments and theories, the circuit for LED driver for Peak Current Control (PCC) is simpler, but the range of its linear dimming is smaller. Additionally, the capability of LED current control with PCC is worse compared to HCC. The range of linear dimming is wider for the LED driver using Hysteretic Current Control (HCC). Moreover, its capability of LED current control for the change of input and output voltage is better than PCC.
Description
Keywords
LED驅動, 遲滯控制, 峰值檢測, 線性調光, PWM調光, LED driver, Hysteretic control, Peak detection, Linear Dimming, PWM Dimming