Driving device of flat panel display and driving method thereof

1. A driving device of a flat panel display configured to receive an image signal and a clock signal, the device comprising:

a driving circuit configured to convert the image signal into pixel data and output the pixel data;

a timing controller configured to generate and output a vertical synchronization signal, a horizontal synchronization signal, a source change enable signal, and a display enable signal using the image signal and the clock signal;

an output buffer comprising an input terminal configured to receive the pixel data and an output terminal connected to the flat panel display; and

a buffer controller connected to the timing controller and the output buffer and configured to control a bias current, applied to the output buffer, to be decreased by a preset value during a predetermined period,

wherein the predetermined period comprises a period from a point at which a charging of a pixel capacitor of the flat panel display is completed based on a current horizontal synchronization signal, up to a next horizontal synchronization signal,

wherein during the period of up to the next horizontal synchronization signal, the buffer controller is configured to control a decreased bias current to return to an original value, by a margin earlier in time than the next horizontal synchronization signal, and

wherein the buffer controller is configured to reduce the bias current by the preset value such that the decreased bias current is larger than zero.

2. The device of claim 1 , wherein the predetermined period further comprises a porch period of the vertical synchronization signal.

3. The device of claim 2 , wherein the buffer controller is configured to perform controlling during a period set considering a time taken for the bias current to change,

a start point of the set period is selected within a front porch period of the vertical synchronization signal, and

an end point of the set period is selected within a back porch period of the vertical synchronization signal.

4. The device of claim 2 ,

wherein during the porch period of the vertical synchronization signal,

a start point of the porch period is selected within a front porch period of the vertical synchronization signal, and

an end point of the porch period is selected within a back porch period of the vertical synchronization signal.

5. The device of claim 4 , wherein the buffer controller is configured to control the bias current to be decreased by using different values for the period of up to the next horizontal synchronization signal and for the porch period of the vertical synchronization signal.

6. The device of claim 1 , wherein the output buffer comprises source amplifiers for driving the flat panel display, and a number of source amplifiers in the output buffer is determined based on a number of pixels included in one line of the flat panel display.

7. The device of claim 1 , wherein the source change enable signal is a signal for changing a signal received by the output buffer.

8. The device of claim 1 , wherein the display enable signal is a signal for determining whether the panel is to be displayed based on the vertical synchronization signal.

9. A driving device of a panel having a 2 to 1 multiplexer structure configured to receive an image signal and a clock signal, the device comprising:

a driving circuit configured to convert the image signal into pixel data and output the pixel data;

a timing controller configured to generate and output a vertical synchronization signal, a horizontal synchronization signal, a source change enable signal, and a display enable signal using the image signal and the clock signal;

an output buffer comprising an input terminal configured to receive the pixel data and an output terminal connected to the panel; and

a buffer controller connected to the timing controller and the output buffer and configured to control a bias current, applied to the output buffer, to be decreased by a preset value during a predetermined period,

wherein the predetermined period comprises a period from a point at which a second switch control signal of the panel rises based on a current horizontal synchronization signal, up to a next horizontal synchronization signal,

wherein during the period of up to the next horizontal synchronization signal, the buffer controller is configured to control a decreased bias current to return to an original value, by a margin earlier in time than the next horizontal synchronization signal, and

wherein the buffer controller is configured to reduce the bias current by the preset value such that the decreased bias current is larger than zero.

10. The device of claim 9 , wherein the predetermined period further comprises a porch period of the vertical synchronization signal.

11. The device of claim 10 , wherein the buffer controller is configured to perform controlling during a period set considering a time taken for the bias current to change,

a start point of the set period is selected within a front porch period of the vertical synchronization signal, and

an end point of the set period is selected within a back porch period of the vertical synchronization signal.

12. The device of claim 10 ,

wherein during the porch period of the vertical synchronization signal,

a start point of the porch period is selected within a front porch period of the vertical synchronization signal, and

an end point of the porch period is selected within a back porch period of the vertical synchronization signal.

13. The device of claim 12 , wherein the buffer controller is configured to control the bias current to be decreased by using different values for the period of up to the next horizontal synchronization signal and for the porch period of the vertical synchronization signal.

14. A driving method of a flat panel display, performed by a driving device that comprises a driving circuit, a timing controller, an output buffer, and a buffer controller, the method comprising:

receiving, by the driving device, an image signal and a clock signal;

outputting, by the timing controller, a vertical synchronization signal, a horizontal synchronization signal, a display enable signal, and a source change enable signal using the image signal and the clock signal;

outputting, by the driving circuit, pixel data of the image signal into the output buffer; and

controlling, by the buffer controller, a bias current applied to the output buffer to be decreased by a preset value, during a predetermined period and a porch period of the vertical synchronization signal,

wherein the predetermined period comprises a period from a point at which a charging of a pixel capacitor of the panel is completed based on a current horizontal synchronization signal up to a next horizontal synchronization signal,

wherein during the period of up to the next horizontal synchronization signal, the buffer controller is configured to control a decreased bias current to return to an original value, by a margin earlier in time than the next horizontal synchronization signal, and

wherein the buffer controller is configured to reduce the bias current by the preset value such that the decreased bias current is larger than zero.

15. The method of claim 14 , wherein during the porch period of the vertical synchronization signal, a start point of the porch period is selected within a front porch period of the vertical synchronization signal, and an end point of the porch period is selected within a back porch period of the vertical synchronization signal.

16. The method of claim 15 , wherein the buffer controller is configured to control the bias current to be decreased using different values for the porch period of the vertical synchronization signal and for the period for the horizontal synchronization signal.