Patent ID: 7158108

Claim:
A column electrode driving circuit for a display device having a matrix of rows and columns of display segments, a display segment comprising at least one pixel capable of gray-scale displaying, the driving circuit comprising: gray-scale voltage producing means including amplifiers, each amplifier having a first input for receiving one value of a range of a plurality of gradually increasing gray-scale voltage values, and having an amplifier output for delivering an output signal in proportion to the voltage level at the input; and selecting means having inputs coupled to the outputs of the amplifiers for selecting and outputting any of the output signals of the amplifiers for each display segment in a row that is being addressed in accordance with an image signal indicative of a gray-scale level to be generated by the display segment, the gray-scale voltage producing means having a predetermined mode wherein a predetermined number of amplifiers, which correspond to a predetermined number of predetermined gray-scale values within the range, are always powered on and other amplifiers are selectively powered on or off, and the selecting means select output signals of the amplifiers which are powered on, the amplifiers which are always powered on being arranged to receive non-sequential gray-scale voltage values ranging from a minimum gray-scale voltage value to a maximum gray-scale voltage value and the other amplifiers being arranged to receive gray-scale voltage values between the minimum and maximum gray-scale voltage values received by the always-on amplifiers such that the full range of gray-scale voltage values is used both when the other amplifiers are powered off and when the other amplifiers are powered on.