An Area-Efficient 10-Bit Buffer-Reused DAC for AMOLED Column Driver ICs

Ming Xia,Hui Wang,Li Tian,Ning Wang,Zunkai Huang,Songlin Feng,Yongxin Zhu

doi:10.3390/electronics9020208

Abstract

In this paper, we proposed an area-efficient 10-bit digital-to-analog converter (DAC) with buffer-reusing method to dramatically relief the severe area exploding issue in high-definition active-matrix organic light-emitting diode (AMOLED) driver integrated circuits (ICs). In our design, we implement the functionalities of a large number of switches and capacitors in conventional DAC by a compact internal buffer. Furthermore, we minimize the buffer capacity requirement by elaborately reusing the indispensable output buffer in the typical column driver. In this way, we can cut down nearly a half of the decoder-switches and simultaneously reduce the capacitor size from 8 C to 3 C without designing an intricate and power-consuming amplifier separately. A prototype 6-channel column driver employing the proposed buffer-reused DAC was fabricated by 0.35 μm 2P3M BCD (Bipolar, CMOS, DMOS) process and its effective layout area per channel is 0.0429 mm2, which is 42.8% smaller than that of the conventional 10-bit R-C DAC. Besides, the measured differential nonlinearity (DNL) and integral nonlinearity (INL) are 0.514 LSB/0.631 LSB, respectively and the maximum value of inter-channel deviation voltage output (DVO) is 3.25 mV. The settling time within 5.6 μs is readily achieved under 1.5 kΩ-resistance and 100 pF-capacitance load. Measurement results indicate that the proposed buffer-reused DAC can successfully minimize the die area while maintaining other required performances.

Highlights

Active-matrix organic light-emitting diode (AMOLED) display has recently emerged as the most promising candidate for the next-generation mainstream display technology
Measurement results indicate that the proposed buffer-reused digital-to-analog converter (DAC) can successfully minimize the die area while maintaining other required performances
An AMOLED driver integrated circuits (ICs) is composed of a column driver, a timing controller, a row driver and a reference generator

Summary

Introduction

Active-matrix organic light-emitting diode (AMOLED) display has recently emerged as the most promising candidate for the next-generation mainstream display technology. It natively presents superior characteristics over other display technologies, such as thinness, lightweight, wide viewing angle, bright color, fast response and low power consumption [1,2,3,4]. The ever-increasing demand of ultra-high-resolution panels leads to a growing community of researches on driver IC, including driving strategy design, circuit optimization, et al Among various driving schemes, the voltage-driving method, which features fast writing time and a reduction in power consumption, has been widely adopted in commercial applications [5].

Methods

Results

Conclusion