High-Speed Column Driver IC Having Buffer Amplifier with Embedded Isolation Switch and Compact Adaptive Biasing for Flat-Panel Displays

Abstract

A high-speed column driver IC with an area-efficient high-slew-rate buffer amplifier is proposed for use in a large-sized, high-resolution TFT-LCD panel application. In the proposed architecture, explicit isolation switches have been embedded into the buffer amplifier resulting in a fast settling response. The amplifier also has a structure that adjusts the tail current of the input stage using a very compact adaptive biasing. The proposed column driver IC, having the proposed buffer amplifier for driving a 55-inch 4K ultra-high-definition (UHD) TV panel, was fabricated in a 0.18-μm 1.8-V low-voltage, 1.2-μm 9-V medium-voltage, and 1.6-μm 18-V high-voltage CMOS process. The performance evaluation results indicated that 90% and 99.9% falling settling times were improved from 1.947 µs to 0.710 µs (63.5% improvement) and 4.131 µs to 2.406 µs (41.7% improvement), respectively. They also indicated that the layout size of the proposed buffer amplifier was reduced from 5580 μm2 to 4402 μm2 (21.1% reduction).