Digital Analog Converter for Low-Temperature Polycrystalline Silicon Flat Panel Displays

• Main Authors: Chih-Ying Lin, 林致穎
• Other Authors: 汪芳興
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/52737150653008081441

碩士 === 國立中興大學 === 電機工程學系所 === 95 === “System on panel (SOP)” products, which integrated peripheral circuits on glass, have been developed by using low-temperature polycrystalline silicon (LTPS) technology. It may eliminate control ICs and driver ICs, reduce the cost of LCD modules, and enhance reliability of products. Among the peripheral circuits, digital-to-analog converters (DACs) and output buffers are important to performance of LCDs because they transform digital signals into analog voltages for controlling gray levels of pixels. First, we represent a novel 8-bit switched-resistor DAC (SR-DAC) based on LTPS technology for high-resolution TFT-LCDs. Reduced chip area and power consumption have been achieved by the voltage division principle and fast switching parallel connection resistors. The measurement results of the rising time and the falling time with 6-V power are 1.16 and 1.22 μsec. The maximum DNL and INL are about 0.3 and 0.6 LSB. Second, a novel complementary current mirror (CCM) type analog buffer is presented for the integrated data drivers. The proposed analog buffer makes use of a p-type and an n-type current-mirrors to amplify the voltage and to achieve large voltage swing. The proposed buffer does not need capacitors and external control signals and features compact size. It has a good linearity from 1-9 V of input voltages with a 10-V power. The offset voltages are within 65.1 mV in middle gray levels. The developed SR-DAC and analog buffer have potential to be applied for SOP products fabricated by LTPS technology.