Patent ID: 7355596

Claim:
A display driver circuit for driving an active matrix type display panel which includes column electrodes and row electrodes in a matrix form, a common electrode disposed opposite to the column electrodes and the row electrodes, and pixel units disposed at intersection points between the column electrodes and the row electrodes, a pixel unit being connected to a column electrode, a row electrode and the common electrode, the display driver circuit comprising: a system interface for inputting display data and a control signal externally; a memory for storing the display data input via the system interface; a register for setting a parameter according to the control signal input via the system interface; a driver circuit for selecting, from a plurality of column voltages corresponding to a plurality of tones, a column voltage corresponding to the display data input from the memory, and outputting the column voltage thus selected to the column electrodes, with the plurality of column voltages being generated by a power source circuit; a control circuit for creating a timing signal based on the parameter in the register; and a short-circuiting circuit for short-circuiting the column electrodes and the common electrode for a period of time shorter than the one scanning period according to the timing signal; wherein the short-circuiting circuit includes a switch circuit disposed on the column electrodes between the pixel units and the driver circuit; wherein the switch circuit switches into either connection between a column electrode on a side of the pixel units and the common electrode or connection between the column electrode on the side of the pixel units and the driver circuit for driving the column electrodes; wherein when connection between the pixel units and a common electrode driver circuit is OFF, the switch circuit makes the connection between the column electrode on the side of the pixel units and the common electrode, without making the connection between the column electrode on the side of the pixel units and the driver circuit for driving the column electrodes; and wherein when the connection between the pixel units and the common electrode driver circuit is ON, the switch circuit makes the connection between the column electrode on the side of the pixel units and the driver circuit for driving the column electrodes, without making the connection between the column electrode on the side of the pixel units and the common electrode.