Patent ID: 6864869

Claim:
A data driver outputting a plurality of analog grayscale voltages to a plurality of data bus lines, comprising: a grayscale voltage generating portion generating the plurality of analog grayscale voltages for a predetermined number of grayscales; a selector portion provided for each of the data bus lines and selecting any one of the plurality of analog grayscale voltages based on grayscale data; a plurality of grayscale voltage lines connected to the grayscale voltage generating portion and provided for each of the plurality of analog grayscale voltages and supplying the analog grayscale voltages to the selector portion; and a switching portion electrically disconnecting the plurality of grayscale voltage lines from the grayscale voltage generating portion during an operation test and electrically connecting the plurality of grayscale voltage lines to the grayscale voltage generating portion during a normal mode of operations; a state setting circuit setting each of the plurality of grayscale voltage lines at a “High” level or a “Low” level independently during the operation test; and a testing control portion for controlling the state selling circuit during the operation test to set a predetermined one of the plurality of grayscale voltage lines at the “High” level, and to set the rest of the plurality of grayscale voltage lines at the “Low” level.