Data line drivers with column initialization transistor
AssigneeThomson Consumer Electronics, Inc.
InventorSherman Weisbrod
Life of this patent
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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.
Claims6
A data line driver for applying a video signal to a column electrode of a display device, comprising:
- a source of said video signal;
- a source of a data ramp signal;
- a first transistor having a first main current conducting terminal coupled to said source of said data ramp signal and a second main current conducting terminal coupled to said column electrode and 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 via a signal path that bypasses said first transistor.
Dependencies are inferred from the claim text.