採用十二位元分段式線性數位類比轉換器之液晶顯示源極驅動電路

A LCD SOURCE DRIVER WITH 12-BIT PIECEWISE LINEAR DIGITAL-TO-ANALOG CONVERTOR

王玉忠(Yu-Chung Wang)

指導教授 ： 黃淑絹

大同大學/電機資訊學院/電機工程學系所/碩士(2011年)

摘要

本篇論文以提高液晶顯示器的色彩飽和度與Gamma校正為前提，設計一個分段式線性十二位元數位類比轉換器。此資料轉換是由八位元電阻串式數位類比轉換器(R-DAC)加上四位元電荷共享式數位類比轉換器(C-DAC)所組成，分別地使用在高位元與低位元的資料轉換。利用分段式線性補償可減少晶片的面積也可增加色彩的濃度，此外也可以加入Gamma校正來修正液晶穿透率對外加資料電壓特性呈線性關係。電路上使用了摺疊疊接式運算放大器搭配Class AB所構成的輸出級，可實現高頻率響應與低靜態功率消耗的緩衝放大器。
本篇源極驅動器是用台積電0.35μm 2P4M CMOS製程設計，工作電壓為5V，資料轉換安定時間也在3.5 μs內，單一通道的緩衝放大器靜態偏壓電流為6.64 μA，兩個通道的晶片佈局面積為865μm × 1250μm (不包含PAD)。

關鍵字

源極驅動器 ； 數位類比轉換器 ； 行驅動器

並列摘要

This thesis is to improve liquid crystal displays for color saturation and Gamma correction, and a piecewise linear 12-bit segmented digital-to-analog converter (DAC) for LCD source driver is proposed. The data conversion is carried out by an 8-bit resistor-string type DAC (R-DAC) and a 4-bit charge sharing DAC (C-DAC), which are used for the most significant bit and least significant bit data conversions, respectively. Piecewise linear compensation is utilized to reduce the die area and increase the effective color depth. In addition, Gamma correction can be applied to amend the characteristic of the liquid crystal transmittance-to-voltage to be a linear relationship. A folded-cascade operational amplifier with a class AB output stage has been designed for high frequency response and low static power of the output buffer amplifier.
The proposed LCD source driver was simulated using TSMC 0.35μm 2P4M CMOS process model. The operation voltage is 5V and the settling time of data converter is within 3.5μs. The static bias current of buffer amplifier is 6.64μA for each channel. The layout area for 2 channels is 865μm × 1250μm (without I/O pads).

並列關鍵字

Source driver ； Digital-to-Analog Converter ； Column driver

參考文獻

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(LCD Driver IC Design)-盧志文.

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