Abstract A video display driver applies a video signal to column electrodes of a liquid crystal display. The display driver includes a reference ramp generator and column data line drivers. A reference ramp signal is combined with the video signal and applied to an input of a comparator. The comparator controls a first transistor that couples a data ramp signal to a given column of pixels. The first transistor at least partially initializes a voltage developed in the given column of pixels prior to an instant when the data ramp signal begins upramping. A second transistor that is coupled in parallel with the first transistor insures that the column voltage is fully initialized.
A data line driver for applying a video signal to a column electrode of a display device, comprising: a source of said video signal; and a source of a data ramp signal; characterized by: a first transistor responsive to said video signal for applying said data ramp signal to said column electrode during a controllable portion of a period of said data ramp signal that varies in accordance with said video signal to develop a column electrode signal at said column electrode; and a second transistor responsive to an initialization control signal and coupled to said column electrode for initializing said column electrode signal.
Claim 2
Dependent Claim
36 words
A data line driver according to Claim 1 further characterized in that a main current conducting current path in said first transistor is coupled in parallel with a main current conducting path of said second transistor.
Claim 3
Dependent Claim
28 words
A data line driver according to Claim 1 further characterized in that said first transistor at least partially initializes said column electrode signal prior to said controllable portion.
Claim 4
Dependent Claim
49 words
A data line driver according to Claim 1 further characterized in that wherein, prior to said controllable portion, each of said first and second transistors couples said column electrode to said data ramp signal source for applying an inactive level of said data ramp signal to said column electrode.
Claim 5
Dependent Claim
37 words
A data line driver according to Claim 4 further characterized in that said first and second transistors apply said inactive level to said column electrode during first and second intervals, respectively, that are at least partially non-overlapping.
Claim 6
Dependent Claim
66 words
A data line driver according to Claim 1 further characterized by: a comparator coupled to a control terminal of said first transistor for controlling said controllable portion, a source of a second control signal coupled to said comparator for calibrating said comparator, said second control signal rendering said first transistor conductive in a manner to provide for at least partial initialization of said column electrode signal.