Patent ID: 6201522
Filing Date: 2001-03-13
Classification: G09G

Abstract:
A power-saving column driver circuit for applying driving voltages to a plurality of columns in a liquid crystal display, the liquid crystal display including an array of pixels arranged in rows and columns, and the liquid crystal display including row driver circuitry for selecting at least one row in the pixel array during a row drive period, the row driver circuitry selecting all rows in the pixel array at least once during a display cycle, said column driver circuit comprising in combination:a. a plurality of voltage drivers, each of said plurality of voltage drivers providing a driving voltage to be applied to a given column of the liquid crystal display during a given row drive period for controlling the pixel located at the given column within the selected row;b. clocking means for providing a control signal switching between a first state and a second state during at least one row drive period of each display cycle;c. a plurality of multiplexers, each of such multiplexers having a control terminal coupled to said clocking means for receiving the control signal, each of such multiplexers having a column terminal coupled to one of the columns of the liquid crystal display, each of such multiplexers having an input terminal coupled to one of said plurality of voltage drivers for receiving the voltage to be applied to a given column of the liquid crystal display during a given row drive period, and each of such multiplexers having a common terminal, each of such multiplexers electrically coupling the column terminal thereof to the common terminal thereof when the control signal is in the first state, and each of such multiplexers electrically coupling the column terminal thereof to the input terminal thereof when the control signal is in the second state;d. a common node coupled to the common terminal of each of said plurality of multiplexers;e. said plurality of multiplexers electrically coupling each of the columns of the liquid crystal display to said common node when the control signal is in its first state, and said plurality of multiplexers coupling each driving voltage produced by said plurality of voltage drivers to a respective one of the columns when the control signal is in its second state.