多通道LED驅動電路

Multi-Channel LED Driver Circuit

邵桂裕(Kuei-Yu Shao)

指導教授 ： 蔡國瑞

崑山科技大學/工程學院/電子工程研究所/碩士(2008年)

摘要

顯示器已成為電子產品的重要零組件，這些顯示器通常需要背光模組來提供光源。高亮度的白光發光二極體(LED)已被視為重要的背光光源。白光LED的優點有價錢便宜、使用壽命長及耗電量低等特性，而且未來白光LED將逐漸取代傳統日光燈泡，因此驅動IC將突顯其重要。
本論文以H-Spice設計三個具有定電流調節模式的LED驅動電路。第一顆晶片，是利用高增益的OP Amp電路、NMOS電晶體與一電阻建立可由外部電壓控制的電流源。透過16個電流鏡產生可驅動16個高亮度白光LED的驅動電路。第二顆晶片，嘗試加入帶差參考電壓電路及利用疊接電流鏡架構。因為晶片本身會發熱，因此需要一個能夠不受溫度的變化而產生太大驅動電流變動的穩定參考電壓，以提升整體電路的精確度及良率。而疊接電流鏡的架構是為了避免每顆LED受製程的影響，導致壓降各有所不同，而影響到電流鏡MOS電晶體的輸出電流。第三顆晶片，則是改良第二顆的Bandgap的架構，而讓LED驅動電路為可調式。
本論文中的LED驅動電路皆採用TSMC 0.35 2P4M之全客戶式設計流程實現與模擬設計。

關鍵字

高亮度LED ； 白光LED ； 驅動電路背光源模組 ； 帶差參考電壓

並列摘要

Displayer has become the inportant part of Electronical prudoct, and it also requires light source by Back light module. High brightness White Emitting Diode(LED) has become the important back light source. The profites of White light Led are cheep price、long life、and low power etc. The White light led is going to replace the traditional Sunlight bulb in the future. Therefore,driver IC will reveal its is important.
In this paper, three LED drivers with uniform current adjustment mechanism were designed by the H-Spice tool. The first chip uses a high-gain OPA, an NMOS transistor and a resistor to implement a current source that can be controlled by an external voltage. It would drive sixteen high-brightness white-light LEDs through sixteen current mirrors. The second chip is trying to add a bandgap reference voltage circuit and to use a cascode mirror circuit construction. Because the chip will produce heat by itself, in order to promote the precision and yield of the whole circuit, we need a steady reference voltage. which will not change a lot when the input voltage and temperature change. The cascode mirror circuit construction is designed to reduce the effects of drain-source voltage drop on the mirrored current because the turn-on voltage of LED is process-dependent. The third chip is designed to improve the bandgap reference construction of the second chip in order to make LED driving current adjustable.
These LED drivers use the full-custom-design methodology of the 0.35μm 2P4M CMOS technology provided by Taiwan Semiconductor Manufacturing Company (TSMC) as the design and simulation platform in this paper.

並列關鍵字

High Brilliant/Brightness LED ； White light LED ； LED Power-Drivers Backlight Source ； bandgap reference voltage

參考文獻

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