SOURCE DRIVER AND DISPLAY DEVICE HAVING THE SAME

Abstract

A source driver and a display device having the same, in which the source driver performs charge sharing on source line driving signals in synchronization with an odd-numbered rising edge of the first output control signal, and outputs analog data signals to source lines of a display panel in synchronization with an even-numbered rising edge of the first output control signal, thereby removing scan line noise.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present invention will be understood in more detail from the following descriptions taken in conjunction with the accompanying drawings in which:

FIG. 1 is a block diagram of a conventional display device;

FIG. 2A is a waveform diagram of signals in a conventional display device driven by a 2H-inversion sub dot pattern, when the common voltage noise is low;

FIG. 2B is a waveform diagram of signals in a conventional display device driven by the 2H-inversion sub dot pattern, when the common voltage noise is high;

FIG. 3 is a functional block diagram of a display device according to an exemplary embodiment of the present invention;

FIG. 4 is a block diagram of a source driver illustrated in FIG. 3 according to an exemplary embodiment of the present invention;

FIG. 5 is a circuit diagram of a control signal generation circuit illustrated in FIG. 4 according to an exemplary embodiment of the present invention;

FIG. 6 is a circuit diagram of an output illustrated in FIG. 4 according to an exemplary embodiment of the present invention;

FIG. 7A is a timing diagram of output control signals in a conventional display device driven according to a 2H-inversion method;

FIG. 7B is a timing diagram of signals supplied to and output from the control signal generation circuit illustrated in FIG. 4, according to an exemplary embodiment of the present invention;

FIG. 8 is a timing diagram of signals in a display device driven by a 2H-inversion sub dot pattern, according to an exemplary embodiment of the present invention; and

FIG. 9 is a flowchart illustrating a method of driving a display device according to an exemplary embodiment of the present invention.

Claims

1. A source driver of a display device comprising: a data latch unit receiving and storing digital image data in response to a horizontal start signal, and outputting the stored digital image data in response to a rising edge of a first output control signal, wherein the horizontal start signal is sequentially shifted in response to a clock signal;an output unit receiving the digital image data from the data latch unit, and supplying analog data signals corresponding to the received digital image data to a display panel in response to a polarity control signal and an activated second output control signal; anda control signal generation circuit generating the second output control signal that is activated in response to an Nth falling edge of the first output control signal and deactivated in response to an (N+2)th rising edge of the first output control signal, in response to the first output control signal and the polarity control signal which controls polarities of the analog data signal supplied to the display panel, where N is an odd number.

2. The source driver of claim 1, wherein the output unit comprises: a digital-to-analog converter generating the analog data signal corresponding to the received digital image data;a plurality of output buffers, each buffering a corresponding analog data signal of the analog data signals;a plurality of output pads, each being connected to a corresponding source line of the display device;a plurality of first switches, each being connected between a corresponding one of the output buffers and a corresponding one of the output pads, and being switched on in response to the second output control signal; anda plurality of second switches, each being connected between output terminals of two corresponding ones of the output buffers and switched on in response to a third output control signal,wherein the control signal generation circuit further generates the third output control signal being deactivated in response to the Nth falling edge of the first output control signal and then activated in response to the (N+2)th rising edge of the first output control signal.

3. The source driver of claim 2, wherein the control signal generation unit comprises: a first latch latching the polarity control signal in response to the first output control signal;a second latch connected to an output terminal of the first latch, and latching a signal from the first latch in response to the first output control signal;an inverter connected to an output terminal of the second latch;a NAND gate receiving the first output control signal and a signal from the inverter, and performing a NAND operation on the received signals; andan overlapping prevention circuit receiving a signal from the NAND gate, and generating the second output control signal and the third output control signal which have a predetermined non-overlapped interval and opposite phases except in the non-overlapped interval.

4. The source driver of claim 2, wherein the second output control signal is maintained in an deactivate state and the third output control signal is maintained in an activate state in an active period of the first output control signal.

5. The source driver of claim 1, wherein a phase of the polarity control signal is inverted every two cycles of the first output control signal.

6. A display device comprising: a controller generating a vertical start signal, output control signals, and digital image data;a display panel having a plurality of source lines and a plurality of gate lines;a source driver supplying analog data signals corresponding to the digital image data to the source lines in response to the output control signals and the digital image data; anda gate driver generating gate line driving signals for sequentially driving the gate lines in response to the vertical start signal,wherein the source driver performs a charge sharing operation for the source lines during an odd-numbered active period of a first output control signal among the output control signals, and supplies the analog data signals to the source lines in response to an even-numbered rising edge of the first output control signal.

7. The display device of claim 6, wherein the source driver comprises: a data latch unit receiving and storing the digital image data in response to a horizontal start signal, and outputting the stored digital image data based on a rising edge of the first output control signal, where the horizontal start signal is sequentially shifted in response to a clock signal among the output control signals;an output unit receiving the digital image data from the data latch unit, and supplying the analog data signals corresponding to the received digital image data to the display panel in response to a polarity control signal and an activated second output control signal among the output control signals; anda control signal generation circuit generating the second output control signal being activated in response to an Nth falling edge of the first output control signal and deactivated in response to an (N+2)th rising edge of the first output control signal, in response to the first output control signal and the polarity control signal that controls polarities of the analog data signals supplied to the display panel, where N is an odd number.

8. The display device of claim 7, wherein the output unit comprises: a digital-to-analog converter generating the analog data signals corresponding to the received digital image data;a plurality of output buffers buffering the corresponding analog data signals, respectively;a plurality of output pads connected to the corresponding source lines of the display panel, respectively;a plurality of first switches, each being connected between a corresponding one of the output buffers and a corresponding one of the output pads, and switched on in response to the second output control signal; anda plurality of second switches, each being connected between output terminals of two corresponding ones of the output buffers, and switched on in response to a third output control signal,wherein the control signal generation circuit further generates the third output control signal being deactivated in response to the Nth falling edge of the first output control signal and activated in response to the (N+2)th rising edge of the first output control signal.

9. The display device of claim 8, wherein the control signal generation unit comprises: a first latch latching the polarity control signal in response to the first output control signal;a second latch latching a signal from an output terminal of the first latch in response to the first output control signal;an inverter connected to an output terminal of the second latch;a NAND gate receiving the first output control signal and a signal from the inverter, and performing a NAND operation on the received signals; andan overlapping prevention circuit receiving a signal from the NAND gate, and generating the second output control signal and the third output control signal that have a predetermined non-overlapped interval and the opposite phases except in the non-overlapped interval.

10. A method of driving source lines of a display device, comprising: receiving and storing digital image data in response to a horizontal start signal that is sequentially shifted in response to a clock signal, and outputting the stored digital image data at a rising edge of a first output control signal;receiving the output digital image data, and supplying analog data signals corresponding to the received digital image data to a display panel in response to a polarity control signal and an activated second output control signal; andconnecting output terminals of output buffers buffering the corresponding analog data signals in response to the second output control signal and a third output signal, where the second output control signal is activated at an Nth falling edge of the first output control signal and deactivated at an (N+2)th rising edge of the first output control signal in response to the first output control signal and the polarity signal that controls polarities of the analog data signals supplied to the display panel, the third output control signal is activated at an Nth rising edge of the first output control signal, and N is an odd number,wherein the second and third output control signals have a predetermined non-overlapped interval and opposite phases except in the non-overlapped interval.

11. A method of driving a display device, comprising: generating output control signals and digital image data;supplying analog data signals corresponding to the digital image data to a plurality of source lines of a display panel in response to the output control signals and the digital image data; andperforming a charge sharing operation for the source lines during an odd-numbered active period of a first output control signal among the output control signals, and supplying the analog data signals to the source lines at an even-numbered rising edge of the first output control signal.