A Comparator-Based Ultra Low-Power Area-Efficient Column Driver Buffer
Date Issued
2007
Date
2007
Author(s)
Lai, Yuan-Chun
DOI
en-US
Abstract
LCD (liquid crystal display) is becoming the most popular technology used for displays in these days. LCD makes displays to be much thinner than traditional cathode ray tube (CRT) technology. Since LCD works on the principle of blocking light rather than emitting it, the power consumption is much less than LED and gas-display displays.
With the evolution of low-power, light-weight, and high-quality displays, the critical demand is to evolve a low-power consumption, high-speed, and high-resolution LCD driver. A LCD driver generally consists of a gate driver, a column driver, reference voltages, and control logic circuits. The column driver is the crucial part for low-power, high-speed, and high-resolution due to its large output loading. Among circuits consisting in a column driver, output buffers consume the most power and determine the speed and resolution. Some LCD column driver buffers were proposed. However, they were almost op amps, which is the reason for high power consumption.
In this thesis, a comparator-based ultra low-power area-efficient column driver buffer is proposed. The proposed approach adds a comparator and a charge pump in the traditional column driver buffer structure. The comparator senses the transients of the input to turn on the charge pump, which is off in the steady state. The slew rate of the circuit is determined by the charge pump but not the op amp. Fabricated in a standard 0.35-μm CMOS technology, the analog buffer can successfully charge or discharge channels in less than 1.1 μs while dissipating 1.1 μA static current form a 5-V power supply. The die size is 0.98 × 0.60 mm2.
Subjects
液晶顯示器
省功率消耗
行驅動器
緩衝器
比較器
LCD
low-power
column driver
buffer
comparator
Type
thesis