Display device and driving method thereof suppressing power voltage ripples
A display device and a driving method thereof can reduce or prevent deterioration of image quality caused by ripples of a power voltage. A display device includes a gamma reference voltage generator generating a plurality of gamma reference voltages using a power voltage. A gamma selection signal generator generates a gamma selection signal corresponding to at least one gamma reference voltage among the gamma reference voltages and the power voltage. A gamma data supply unit stores a plurality of gamma data sets and outputs a gamma data set corresponding to the gamma selection signal from among the gamma data sets. A data driver generates a data signal using the gamma data set supplied from the gamma data supply unit and the gamma reference voltages. A display unit includes data lines transmitting the data signal.
1. A display device comprising:
a gamma reference voltage generator circuit generating a plurality of gamma reference voltages from a power voltage;
a gamma selection signal generator circuit generating a gamma selection signal corresponding to at least one gamma reference voltage of the plurality of gamma reference voltages and the power voltage;
a gamma data supply circuit storing a plurality of gamma data sets, and outputting a gamma data set corresponding to the gamma selection signal from among the plurality of gamma data sets;
a data driver generating a data signal, using the gamma data set output from the gamma data supply circuit and the gamma reference voltages; and
a display unit which comprises a plurality of data lines carrying the data signal,
wherein the gamma selection signal generator circuit includes:
a representative value calculator circuit calculating a representative value of the power voltage in each of a plurality of frame periods; and
a comparator outputting a comparison value by detecting a difference between the representative value and the at least one gamma reference voltage, and
wherein the comparator is synchronized with a start frame control signal supplied in each of the plurality of frame periods to output the comparison value.
2. The display device of claim 1 , wherein the gamma selection signal generator circuit further includes:
an analog-to-digital converter generating the gamma selection signal corresponding to the comparison value.
3. The display device of claim 1 , wherein the gamma data supply circuit includes:
a gamma data storage circuit in which the plurality of gamma data sets are stored; and
a gamma selector circuit configured to selectively output a gamma data set corresponding to the gamma selection signal from among the plurality of gamma data sets.
4. The display device of claim 3 , wherein the gamma data storage circuit includes a plurality of look-up tables in which a plurality of gamma voltages included in the respective gamma data sets are stored.
5. The display device of claim 1 , wherein each of the plurality of gamma data sets includes a plurality of gamma voltages having values between the gamma reference voltages.
6. The display device of claim 1 , further comprising a timing controller controlling the gamma selection signal generator circuit and the data driver.
7. The display device of claim 6 , wherein the gamma data supply circuit is included within the timing controller.
8. A display device comprising:
a gamma reference voltage generator circuit generating a plurality of gamma reference voltages from a power voltage;
a gamma selection signal generator circuit generating a gamma selection signal corresponding to at least one gamma reference voltage of the plurality of gamma reference voltages and the power voltage;
a gamma data supply circuit storing a plurality of gamma data sets, and outputting a gamma data set corresponding to the gamma selection signal from among the plurality of gamma data sets;
a data driver generating a data signal, using the gamma data set output from the gamma data supply circuit and the gamma reference voltages; and
a display unit which comprises a plurality of data lines carrying the data signal,
wherein the data driver includes a plurality of sub-data drivers, each of which supplies a data signal to some data lines from among the plurality of data lines,
wherein the gamma selection signal generator circuit includes a plurality of sub-gamma selection signal generators provided in respective sub-data drivers of the plurality of sub-data drivers, and
wherein the gamma data supply circuit outputs the gamma data set to each of the plurality of sub-data drivers, the gamma data set corresponding to the gamma selection signal input from each of the plurality of sub-gamma selection signal generators.
9. A method of driving a display device, the method comprising:
comparing a power voltage with at least one gamma reference voltage from among a plurality of gamma reference voltages and outputting a resulting comparison value;
generating a gamma selection signal corresponding to the comparison value;
selecting a gamma data set corresponding to the gamma selection signal from
among a plurality of previously stored gamma data sets, and outputting the selected gamma data set;
generating a data signal corresponding to input data, using the selected gamma data set and the plurality of gamma reference values; and
displaying an image corresponding to the generated data signal,
wherein the outputting of the comparison value includes:
calculating a representative value of the power voltage synchronized with a start frame control signal supplied in each of a plurality of frame periods; and
generating the comparison value by detecting a difference between the representative value and the at least one gamma reference voltage.
10. The method of claim 9 , wherein the generating of the gamma selection signal includes generating a digital code corresponding to a voltage range of the comparison value.