Data driver and display device including the same
A display device includes a display panel including data lines and pixels electrically connected to the data lines. The data driver supplies data signals to the data lines. The data driver includes: a first output buffer electrically connected to a first data line of the data lines, the first output buffer outputting a first data signal to the first data line; and a first comparator electrically connected to an output terminal of the first output buffer, the first comparator comparing a first slew rate of the first data signal with a first reference slew rate.
1. A display device comprising:
a display panel including:
data lines; and
pixels electrically connected to the data lines; and
a data driver that supplies data signals to the data lines,
wherein the data driver includes:
a first output buffer electrically connected to a first data line of the data lines, the first output buffer outputting a first data signal to the first data line; and
a first comparator electrically connected to an output terminal of the first output buffer, the first comparator comparing a first slew rate of the first data signal with a first reference slew rate;
wherein the first reference slew rate is based on a contact resistance between the data driver and one or more of the data lines.
2. The display device of claim 1 , wherein the first slew rate of the first data signal is changed according to a resistance of a contact resistor disposed between the first output buffer and the first data line.
3. The display device of claim 2 , further comprising:
a controller that determines whether the resistance is within a normal range based on a comparison result of the first comparator.
4. The display device of claim 1 , wherein
the first data signal is a square wave having a first voltage level or a second voltage level, and
the first comparator determines a transition time from the first voltage level to the second voltage level as the first slew rate of the first data signal.
5. The display device of claim 4 , wherein the first comparator includes:
a first counter that calculates the transition time based on a reference clock signal; and
a digital comparator that compares an output of the first counter with a reference transition time corresponding to the first reference slew rate.
6. The display device of claim 1 , wherein the data driver further includes:
a second output buffer electrically connected to a second data line of the data lines, the second output buffer outputting a second data signal to the second data line; and
a multiplexer that selectively transfers an output of the output terminal of the first output buffer and an output of an output terminal of the second output buffer to the first comparator.
7. The display device of claim 6 , wherein,
in a first period, the multiplexer transfers the output of the output terminal of the first output buffer to the first comparator, and the first comparator outputs a first comparison result corresponding to a first resistance between the first output buffer and the first data line, and
in a second period, the multiplexer transfers the output of the output terminal of the second output buffer to the first comparator, and the first comparator outputs a second comparison result corresponding to a second resistance between the second output buffer and the second data line.
8. The display device of claim 1 , wherein
the data driver further includes:
a second output buffer electrically connected to a second data line of the data lines, the second output buffer outputting a second data signal to the second data line;
a second comparator; and
a multiplexer that transfers an output of the output terminal of the first output buffer to the first comparator, and transfers an output of the second output buffer to the second comparator, and
wherein the second comparator compares a second slew rate of the second data signal with a second reference slew rate.
9. The display device of claim 8 , wherein the second reference slew rate is different from the first reference slew rate.
10. The display device of claim 8 , wherein the data driver further includes:
a third output buffer electrically connected to a third data line of the data lines, the third output buffer outputting a third data signal to the third data line;
a fourth output buffer electrically connected to a fourth data line of the data lines, the fourth output buffer outputting a fourth data signal to the fourth data line; and
a switching part that electrically connects the first output buffer or the third output buffer to the multiplexer, and electrically connects the second output buffer or the fourth output buffer to the multiplexer.
11. The display device of claim 10 , wherein with respect to one or more pixels in a same row among the pixels,
a first output timing at which the first output buffer outputs the first data signal is equal to a second output timing at which the second output buffer outputs the second data signal, and
a third output timing at which the third output buffer outputs the third data signal is different from the first output timing of the first output buffer.
12. A display device comprising:
a display panel including:
data lines; and
pixels electrically connected to the data lines; and
a data driver that supplies data signals to the data lines, wherein the data driver includes a plurality of data driver ICs (integrated circuits), and each of the plurality of data driver ICs includes:
output buffers, each of the output buffers outputting a data signal to a corresponding data line among the data lines;
a comparator that compares a slew rate of a signal provided to an input terminal thereof with a reference slew rate; and
a multiplexer electrically connected between the output buffers and the comparator, the multiplexer sequentially providing data signals output from the output buffers to the comparator;
wherein the reference slew rate is based on a contact resistance between the data driver and one or more of the data lines.
13. The display device of claim 12 , further comprising:
a timing controller electrically connected to the plurality of data driver ICs through a feedback line, wherein
the comparator generates a feedback signal by comparing the slew rate of the signal with the reference slew rate, and
the plurality of data driver ICs sequentially provide the feedback signal to the timing controller through the feedback line.
14. The display device of claim 13 , wherein the slew rate is changed according to a resistance of a contact resistor between an output buffer outputting the signal among the output buffers and a corresponding data line among the data lines.
15. The display device of claim 14 , wherein the timing controller determines whether the resistance of each of the data lines is within a normal range based on a time at which the feedback signal is received.
16. A data driver comprising:
a digital-analog converter that generates a first data signal corresponding to grayscale values of image data;
a first output buffer that outputs the first data signal to the outside; and
a first comparator electrically connected to an output terminal of the first output buffer, the first comparator comparing a first slew rate of the first data signal with a first reference slew rate;
wherein the first reference slew rate is based on a contact resistance between the data driver and one or more data lines.
17. The data driver of claim 16 , wherein
the first data signal is a square wave having a first voltage level or a second voltage level, and
the first comparator determines a transition time from the first voltage level to the second voltage level as the first slew rate of the first data signal.
18. The data driver of claim 17 , wherein the first comparator includes:
a first counter that calculates the transition time based on a reference clock signal; and
a digital comparator that compares an output of the first counter with a reference transition time corresponding to the first reference slew rate.
19. The data driver of claim 16 , wherein the data driver further includes:
a second output buffer that outputs a second data signal generated by the digital-analog converter to the outside; and
a multiplexer that selectively transfers an output of the output terminal of the first output buffer and an output of an output terminal of the second output buffer to the first comparator.
20. The data driver of claim 19 , wherein
in a first period, the multiplexer transfers an output of the output terminal of the first output buffer to the first comparator, and the first comparator outputs a first comparison result corresponding to the first output buffer, and
in a second period, the multiplexer transfers an output of the output terminal of the second output buffer to the first comparator, and the first comparator outputs a second comparison result corresponding to the second output buffer.