Data line driving circuit for liquid crystal display device and method for controlling the same

1. A data line driving circuit for a liquid crystal display device comprising: a plurality of first data lines applied with a positive potential, a plurality of second data lines applied with a negative potential, comparison units that compare with a reference voltage at least one of a potential at a first common line connected to the plurality of first data lines and a potential at a second common line connected to the plurality of second data lines, and switches that are controlled so that the first data lines and the second data lines are set to a connection state or an interruption state according to a comparison result by the comparison units, wherein the potential at the first common line is different than a potential at the second common line, and wherein the plurality of first data lines are commonly switched according to the comparison results from the comparison units and the plurality of second data lines are commonly switched and separate from the switching of the first data lines according to the comparison results from the comparison units.

2. The data line driving circuit according to claim 1 , wherein when the potential at the first common line is compared with a reference voltage, the comparison units use a positive reference voltage greater than a potential obtained by averaging the potentials at the first and second data lines as the reference voltage.

3. The data line driving circuit according to claim 1 , wherein when the potential at the second common line is compared with a reference voltage, the comparison units use a negative reference voltage less than the potential obtained by averaging the potentials at the first and second data lines as the reference voltage.

4. The data line driving circuit according to claim 2 , wherein the positive reference voltage is a potential close to a middle value of a driving range of the first data lines.

5. The data line driving circuit according to claim 3 , wherein the negative reference voltage is a potential close to a middle value of a driving range of the second data lines.

6. The data line driving circuit according to claim 2 , wherein the positive reference voltage is substantially ¾ potential of a power supply voltage.

7. The data line driving circuit according to claim 3 , wherein the negative reference voltage is substantially ¼ potential of the power supply voltage.

8. A data line driving circuit for a liquid crystal display device comprising: a plurality of first data lines applied with a positive potential, a plurality of second data lines applied with a negative potential, a first comparison unit that compares with a first reference voltage a potential at a first common line connected to the plurality of first data lines, a second comparison unit that compares with a second reference voltage a potential at a second common line connected to the plurality of second data lines, a first switch that is controlled so that the first data lines and a common node are set to a connection state or an interruption state according to a comparison result by the first comparison unit, and a second switch that is controlled so that the second data lines and the common node are set to a connection state or an interruption state according to a comparison result by the second comparison unit, wherein the potential at the first common line is different than a potential at the second common line, and wherein the plurality of first data lines are commonly switched by the first switch according to the comparison results from the first comparison unit and the plurality of second data lines are commonly switched by the second switch and separate from the switching of the first data lines according to the comparison results from the second comparison unit.

9. The data line driving circuit according to claim 8 , wherein the first reference voltage is greater than a potential obtained by averaging the potentials at the first and second data lines, while the second reference voltage is less than the potential obtained by averaging the potentials at the first and second data lines.

10. The data line driving circuit according to claim 8 , wherein the first reference voltage is a potential close to a middle value of a driving range of the first data lines, while the second reference voltage is a potential close to a middle value of a driving range of the second data lines.

11. The data line driving circuit according to claim 8 , wherein the first reference voltage is substantially ¾ potential of a power supply voltage, while the second reference voltage is substantially ¼ potential thereof.

12. A method for controlling a data line driving circuit for a liquid crystal display, the circuit comprising a plurality of first data lines applied with a positive potential and a plurality of second data lines applied with a negative potential, the method comprising: comparing at least one of a first potential at the first data lines and a second potential at the second data lines with a reference voltage; and controlling the first data lines and the second data lines to be a connection state or an interruption state according to a comparison result from the comparing, wherein the first potential is different than the second potential and, wherein the plurality of first data lines are commonly switched according to the comparison and the plurality of second data lines are commonly switched and separate from the switching of the first data lines according to the comparison during a column inversion driving.