24.1: A Programmable Analog Reference Memory for Adaptive Gamma Correction

Abstract

A CMOS Integrated Circuit stores multiple sets of gamma reference voltages in re-programmable non-volatile analog memory. Stored gamma curves are selected by simple address inputs, allowing adaptive correction of video content, color, ambient light, backlight or temperature. The device offers significant performance and cost advantages compared to competing solutions.

P‐50: Elimination of Gamma Variation in Large LCD Panels for Television, Notebook and Monitor Applications

“…A programmable voltage reference technology has been developed that allows gamma reference voltages to be set to accurate voltages across multiple displays independent of the panel power supply. The technology has been deployed on several products for the LCD Television, Monitor and Notebook applications and described previously [5,6].…”

P-49: A Programmable Gamma Reference Buffer with Integrated Backlight Control

“…Eighteen gamma voltages, VGMA0 through VGMA17, a single backlight control voltage DIM ADJ , and a trimmed VCOM voltage, VCOM OUT , are output from summing circuits on the right of the figure. The analog memory array and summing circuits were described previously at SID 05 in the paper titled "A Programmable Reference Memory for Adaptive Gamma Correction" [1] and will not be repeated here. Programming accuracy is valid over the complete range of gamma voltages and thus provides an overall accuracy of 0.03% over 18V.…”