Area-Efficient Time-Shared Digital-to-Analog Converter With Dual Sampling for AMOLED Column Driver IC’s

Abstract

This paper presents a 24-channel time-shared 8-bit digital-to-analog converter (DAC) with dual sampling to minimize the effective channel area of the column driver integrated circuit (IC) for high-resolution active-matrix organic light emitting diodes (AMOLED). The proposed time-shared DAC significantly reduces the effective channel area of the column driver IC, since a single high-speed DAC is shared among multi channels. The dual-sampling architecture for the output amplifiers also reduces the power consumption of the column driver IC, where the operating time of the time-shared DAC and the output amplifier is efficiently handled during the limited 1-horizontal time. The sampling accuracy of the dual-sampling architecture is improved by a simple dummy switch and a source follower. The proposed time-shared DAC with the dual sampling is implemented by a 0.13- $\mu \text{m}$ high-voltage complementary metal-oxide-semiconductor process and integrated in a 960-channel column driver IC, while the effective channel area of the column driver IC is 5520 $\mu \text{m}^{2}$ . As a result of driving an 11-inch-wide quad extended graphics array AMOLED panel by using the prototype column driver IC, the panel uniformly generates a clear image.