Patent ID: 6747628
Filing Date: 2004-06-08
Classification: G09G

Abstract:
A liquid crystal display controller on a semiconductor chip and for use with a liquid crystal display panel having a plurality of common electrodes, segment electrodes and pixels arranged in the form of a dot-matrix and a microprocessor unit, the liquid crystal display controller comprising:a segment driver outputting segment signals to be provided to the segment electrodes depending upon display data; a common driver outputting common signals to be provided to the common electrodes to selectively driving the common electrodes in a time-division manner; a timing generation circuit controlling a drive duty of time-division drive for the common driver; a drive bias circuit controlling a bias ratio for driving the liquid crystal display panel; a boosting circuit generating a liquid crystal drive voltage for the liquid crystal display panel; a drive duty-setting circuit capable of setting a value for determining the drive duty of the timing generation circuit; and a drive bias-setting circuit capable of setting a value for determining the bias ratio of the drive bias circuit, wherein the value of the drive duty-setting circuit and the value of the drive bias-setting circuit are changed by the microprocessor unit at a time when a pattern is to be partially displayed on the liquid crystal display panel.