隨著手機、筆記型電腦及顯示面板的蓬勃發展，LED驅動電路近年來被廣泛應用於各類民生及商用產品中。不過LED由於因製程因素，導致在相同順向電流下，RGB三色LED所需要的順向電壓皆不相同，藍色最高，依序為綠色、紅色。若將固定電壓加諸在LED串列上，會造成冗餘電壓位於電流調節電路中，也將間接導致整體系統效率下降。
本文提出「具改善動態電壓響應之高效率節能控制RGB-LED驅動器」，主體轉換器選用升壓轉換器。透過切換式電流調節電路，分時輪流導通RGB-LED串列並抓取電壓進行回授，自適應地產生參考電壓，進而調節升壓轉換器之輸出電壓，以確保當單一LED串列導通時，其轉換器輸出能鎖定在最低導通需求，降低晶片所需功率消耗。此外，回授控制採用漣波控制中的自適應導通時間控制，不僅能加快LED串列在切換時之電壓回復速度，並確保當所有LED串列在進行切換時，升壓轉換器的切換頻率能維持固定，以降低EMI雜訊干擾。
本文採用TSMC 0.18µm 1P6M T18HVG2製程實現，晶片面積為3.022 ×1.65 mm2。功率級輸入電壓為5至8V，輸出電壓為11.75V至14.75V，LED串列驅動電流為100mA，切換頻率為1MHz，電感與輸出電容分別為18µH及5µF。相較於現今相關文獻之LED驅動電路，本文所提出之「具改善動態電壓響應之高效率節能控制RGB-LED驅動器研製」，功率消耗約可再額外減少11%。

In recent years, with the vigorous development of mobile phones, notebook computers and display panels, LED driver circuits have been widely used in various consumer and commercial products. However, due to LED process factors, the forward voltages under the same forward current required to make RGB, three-color LEDs, are different: blue requires the most, green the second, while red the least. When a fixed voltage is applied to the LED strings, redundant voltages in the current regulator come into existence, which indirectly leads to a decrease in overall efficiency.
This paper proposes a high efficiency RGB-LED driver with energy-saving and optimized dynamic voltage scaling control technique. A boost converter is used to be the main converter. It uses a switching current regulator, which takes turns to conduct different RGB-LED strings, and capture the feedback voltages from the RGB-LED strings, then generates an adaptive reference voltage that regulates the output voltage of the boost converter. So when either one of the LED strings is conducted, the output voltage of converter is assured to be locked to the minimum conducted requirement so as to reduce power consumption.
Besides, this design uses ripple-based adaptive on-time control, which not only accelerates the voltage recovery response when LED strings are being switched but also makes sure of a fixed switching frequency of the boost converter in order to reduce EMI noise.
This paper is realized by TSMC 0.18µm 1P6M T18HVG2 process, and the size of chip is 3.022 ×1.65 mm2.The power stage input voltage is from 5V to 8V and output voltage is from 11.75V to 14.75V. LED strings drive current is 100mA, and switching frequency is 1MHz. The external inductor and output capacitor are 18µH and 5µF respectively.

Compared with current related literature on LED driver circuit, the high efficiency RGB-LED driver with energy-saving and optimized dynamic voltage scaling control technique proposed on this paper can reduce power consumption by an additional 11%.

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