Charge sharing method for reducing power consumption and apparatuses performing the same

1. A charge sharing method for a display driver that uses Z-inversion, the method comprising:

receiving a first row of data for a plurality of source lines;

receiving a second row of data for the plurality of source lines;

for each source line of the plurality of source lines, determining whether a change amount between data for that source line from the first row of data and data for that source line from the second row of data is above a threshold;

first controlling whether to perform charge sharing among a first group of source lines of the plurality of source lines based on the determinations for that first group of source lines;

second controlling whether to perform charge sharing among a second group of source lines of the plurality of source lines based on the determinations for that second group of source lines,

wherein the first controlling includes controlling connection between a first charge sharing line and each of the first group of source lines,

wherein the second controlling includes controlling connection between a second charge sharing line and each of the second group of source lines, and

wherein the connection between the first charge sharing line and at least one source line of the first group of source lines is independent from the connection between the second charge sharing line and at least one source line of the second group of source lines; and

based on the determinations for the first group of source lines;

counting a first number of determinations for which a charge associated with the data for a respective source line increases more than a first threshold amount;

counting a second number of determinations for which a charge associated with the data for a respective source line decreases more than a second threshold amount; and

controlling whether to perform the charge sharing for the first group of source lines based on the first number of determinations and the second number of determinations.

2. The charge sharing method of claim 1 , wherein:

the first group of source lines includes only odd-numbered source lines of the display driver; and

the second group of source lines includes only even-numbered source lines of the display driver.

3. The charge sharing method of claim 1 , wherein:

the first group of source lines includes source lines that share a first polarity during operation of the source driver; and

the second group of source lines includes source lines that share a second polarity opposite the first polarity during operation of the source driver.

4. The charge sharing method of claim 1 , further comprising:

dynamically selecting the first group of source lines based on the determinations for the plurality of source lines.

5. The charge sharing method of claim 1 , wherein:

the first reference value is a predetermined percentage of the total number of source lines of the first group of source lines; and

the second reference value is a predetermined percentage of the total number of source lines of the first group of source lines.

6. The charge sharing method of claim 1 , further comprising:

performing the charge sharing when the first number of determinations is above a first reference value and the second number of determinations is above a second reference value.

7. The charge sharing method of claim 6 , wherein the first reference value is the same as the second reference value.

8. A charge sharing method for a display driver, the method comprising:

receiving a first row of data for a first row of source lines;

receiving a second row of data for a second row of source lines;

for each source line of at least a first group of the source lines, first determining whether a change amount between data for that source line from the first row of data and data for that source line from the second row of data is above a threshold;

for each source line of at least a second group of the source lines, second determining whether a change amount between data for that source line from the first row of data and data for that source line from the second row of data is above a threshold;

performing selective charge sharing based on the determinations for the first group of source lines and second group of source lines,

wherein the performing includes at least one of first controlling connection between a first charge sharing line and each of the first group of source lines, and second controlling connection between a second charge sharing line and each of the second group of source lines, and

wherein the connection between the first charge sharing line and at least one source line of the first group of source lines is independent from the connection between the second charge sharing line and at least one source line of the second group of source lines; and

based on the determinations for the first group of source lines:

counting a first number of determinations for which a charge associated with the data for a respective source line increases more titan a first threshold amount;

counting a second number of determinations for which a charge associated with the data for a respective source line decreases more than a second threshold amount: and

controlling whether to perform the charge sharing for the first group of source lines based on the first number of determinations and the second number of determinations.

9. The charge sharing method of claim 8 , wherein:

performing selective charge sharing includes selecting a group of source lines to be connected to each other for a charge sharing operation.

10. The charge sharing method of claim 8 , wherein:

the first group of source lines includes only odd-numbered source lines of the display driver; and

the second group of source lines includes only even-numbered source lines of the display driver.

11. The charge sharing method of claim 8 , wherein:

the first group of source lines includes source lines that share a first polarity during operation of the source driver; and

the second group of source lines includes source lines that share a second polarity opposite the first polarity during operation of the source driver.

12. The charge sharing method of claim 8 , wherein:

performing selective charge sharing includes selecting whether or not to perform charge sharing based on the determinations for the first group of source lines and second group of source lines.

13. The charge sharing method of claim 12 , wherein:

performing selective charge sharing includes, during each of a plurality of blanking intervals, selecting whether or not to perform charge sharing.

14. The charge sharing method of claim 8 , further comprising:

performing the charge sharing when the first number of determinations is above a first reference value and the second number of determinations is above a second reference value.

15. The charge sharing method of claim 14 , wherein the first reference value is the same as the second reference value.

16. A charge sharing method for a display driver that includes a plurality of first source lines coupled to a respective plurality of first buffers through a respective plurality of first switches, a plurality of second source lines coupled to a respective plurality of second buffers through a respective plurality of second switches, a plurality of third switches respectively coupled to the plurality of first buffers and a plurality of fourth switches respectively coupled to the plurality of second buffers, a first charge sharing line, and a second charge sharing line, the method comprising:

receiving a first set of data at the plurality of first source lines and a second set of data at the plurality of second source lines at a first period of time when each of the plurality of third switches and each of the plurality of fourth switches are in a first state that causes the first charge sharing line and the second charge sharing line to be disconnected from the plurality of first source lines and plurality of second source lines;

for each source line of the plurality of first source lines and the plurality of second source lines, determining whether a change amount between data of a particular set of data for that source line and data of a next set of data for that source line is above a threshold; and

based on the determining for the plurality of first source lines:

counting a first number of determinations for which a charge associated with the data for a respective source line increases more than a first threshold amount;

counting a second number of determinations for which a charge associated with the data for a respective source line decreases more than a second threshold amount; and

controlling whether to perform the charge sharing for the plurality of first source lines based on the first number of determinations and the second number of determinations,

wherein charge sharing includes changing the state of each of the plurality of third switches and each of the plurality of fourth switches to a second state to cause the plurality of first source lines to connect to the first charge sharing line and the plurality of second source lines to connect to the second charge sharing line, wherein the plurality of first source lines are electrically connected to the first charge sharing line through respective ones of the third switches, and the plurality of second source lines are electrically connected to the second charge sharing line through respective ones of the fourth switches and are not connected to the first charge sharing line through the third switches.

17. The method of claim 16 , wherein:

the changed state of each of the plurality of first switches and each of the plurality of second switches occurs during a blanking interval following the first period of time.