Display device including lookup table based voltage driver and method of operating the same
A display device includes: a display panel including a pixel, a voltage generator configured to generate a plurality of driving voltages for operating the pixel, and a driver configured to generate a data signal transmitted to the pixel, and to determine each of voltage levels of a second power voltage, a first initialization voltage, a second initialization voltage, and a first low voltage among the plurality of driving voltages based on a luminance level of an image displayed by the display panel, and the voltage generator is configured to generate the determined second power voltage, first initialization voltage, second initialization voltage, and first low voltage.
1 . A display device comprising:
a display panel including a pixel;
a voltage generator configured to generate a plurality of driving voltages for operating the pixel;
a memory including a plurality of lookup tables; and
a driver configured to generate a data signal transmitted to the pixel, and to determine each of voltage levels of a power voltage, a first initialization voltage, a second initialization voltage, and a first low voltage among the plurality of driving voltages based on a luminance level of an image displayed by the display panel,
wherein the voltage generator is configured to generate the determined power voltage, first initialization voltage, second initialization voltage, and first low voltage, and
wherein the driver comprises:
a first voltage determiner configured to determine the voltage level of the power voltage based on a first lookup table among the plurality of lookup tables;
a second voltage determiner configured to determine the voltage level of the first initialization voltage based on a second lookup table among the plurality of lookup tables; and
a third voltage determiner configured to determine the voltage level of the second initialization voltage based on a third lookup table among the plurality of lookup tables.
2 . The display device according to claim 1 , wherein the power voltage is supplied to a cathode electrode of a light emitting element included in the pixel,
the first initialization voltage is a voltage for initializing a gate electrode of a driving transistor included in the pixel,
the second initialization voltage is a voltage for initializing an anode electrode of the light emitting element, and
the first low voltage is a voltage for turning on a P-type transistor included in the pixel.
3 . The display device according to claim 1 , wherein the driver further comprises a fourth voltage determiner configured to determine the voltage level of the first low voltage based on the voltage level of the power voltage, the voltage level of the first initialization voltage, and the voltage level of the second initialization voltage.
4 . The display device according to claim 3 , wherein the fourth voltage determiner is configured to determine the voltage level of the first low voltage based on following Formula 1:
V
GL
1
=
min
(
EL
V
SS
,
V
int
1
,
V
int
2
)
-
ΔV
1
,
[
Formula
1
]
where in the Formula 1, VGL1 is the first low voltage, ELVSS is the power voltage, Vint1 is the first initialization voltage, Vint2 is the second initialization voltage, and ΔV1 is a predetermined positive number.
5 . The display device according to claim 4 , wherein ΔV1 of the Formula 1 is a threshold voltage of the P-type transistor included in the pixel.
6 . The display device according to claim 3 , wherein the driver further comprises a fifth voltage determiner configured to determine a voltage level of a second low voltage for turning off an N-type transistor included in the pixel among the plurality of driving voltages, based on the voltage level of the first low voltage.
7 . The display device according to claim 6 , wherein the fifth voltage determiner is configured to determine the voltage level of the second low voltage based on following Formula 2:
V
GL
2
=
V
GL
1
+
ΔV2
,
[
Formula
2
]
where in the Formula 2, VGL2 is the second low voltage, and ΔV2 is a predetermined positive number.
8 . The display device according to claim 7 , wherein the fifth voltage determiner is configured to determine the ΔV2 of the Formula 2 based on the luminance level.
9 . The display device according to claim 1 , wherein the driver further comprises:
a fourth voltage determiner configured to determine the voltage level of the first low voltage based on a fourth lookup table among the plurality of lookup tables; and
a fifth voltage determiner configured to determine a voltage level of a second low voltage for turning off an N-type transistor included in the pixel among the plurality of driving voltages based on a fifth lookup table among the plurality of lookup tables.
10 . The display device according to claim 1 , further comprising a temperature sensor configured to sense a temperature around the display panel,
wherein the driver is configured to determine each of the voltage levels of the power voltage, the first initialization voltage, the second initialization voltage, and the first low voltage based on a temperature sensing value generated by the temperature sensor and the luminance level of the image displayed by the display panel, and
the voltage generator is configured to generate the determined power voltage, first initialization voltage, second initialization voltage, and first low voltage.
11 . The display device according to claim 1 , further comprising:
an illuminance sensor configured to sense an illuminance around the display panel,
wherein the driver is configured to determine the luminance level based on an illuminance sensing value generated by the illuminance sensor and image data input to the display device.
12 . An electronic device comprising:
a display panel including a pixel;
a voltage generator configured to generate a plurality of driving voltages for operating the pixel;
a memory including a plurality of lookup tables; and
a driver configured to generate a data signal transmitted to the pixel, and to determine each of voltage levels of a power voltage, a first initialization voltage, a second initialization voltage, and a first low voltage among the plurality of driving voltages based on a luminance level of an image displayed by the display panel,
wherein the voltage generator is configured to generate the determined power voltage, first initialization voltage, second initialization voltage, and first low voltage, and
wherein the driver comprises:
a first voltage determiner configured to determine the voltage level of the power voltage based on a first lookup table among the plurality of lookup tables;
a second voltage determiner configured to determine the voltage level of the first initialization voltage based on a second lookup table among the plurality of lookup tables; and
a third voltage determiner configured to determine the voltage level of the second initialization voltage based on a third lookup table among the plurality of lookup tables.
13 . A method of operating a display device, the method comprising:
determining each of voltage levels of a power voltage and an initialization voltage supplied to a pixel of the display device, based on a luminance level;
determining a voltage level of a first low voltage applied to a gate of a first type transistor included in the pixel, based on the determined voltage levels of the power voltage and the initialization voltage; and
determining a voltage level of a second low voltage applied to a gate of a second type transistor included in the pixel, based on the voltage level of the first low voltage, and
wherein:
determining each of voltage levels of the power voltage and the initialization voltage includes determining each of voltage levels of the power voltage, the first initialization voltage, and the second initialization voltage supplied to a pixel of the display device, based on first to third lookup tables;
determining the voltage level of the first low voltage includes determining the voltage level of the first low voltage applied to the gate of the first type transistor, based on a fourth lookup table; and
determining the voltage level of the second low voltage includes determining the voltage level of the second low voltage applied to the gate of the second type transistor, based on a fifth lookup table.
14 . The method according to claim 13 , wherein the first type transistor is a P-type transistor, the second type transistor is an N-type transistor, the voltage level of the first low voltage is a voltage level for turning on the P-type transistor, and the voltage level of the second low voltage is a voltage level for turning off the N-type transistor.
15 . The method according to claim 13 , wherein the initialization voltage includes a first initialization voltage for initializing a gate electrode of a driving transistor included in the pixel and a second initialization voltage for initializing an anode electrode of a light emitting element included in the pixel, the power voltage is supplied to a cathode electrode of the light emitting element included in the pixel, and
determining the voltage level of the first low voltage includes determining the voltage level of the first low voltage based on following Formula 1:
V
GL
1
=
min
(
EL
V
SS
,
V
int
1
,
V
int
2
)
-
ΔV
1
,
[
Formula
1
]
where in the Formula 1, VGL1 is the first low voltage, ELVSS is the power voltage, Vint1 is the first initialization voltage, Vint2 is the second initialization voltage, and ΔV1 is a predetermined positive number,
wherein determining the voltage level of the second low voltage includes determining the voltage level of the second low voltage based on following Formula 2:
V
GL
2
=
V
GL
1
+
ΔV2
,
[
Formula
2
]
where in the Formula 2, VGL2 is the second low voltage, and ΔV2 is a predetermined positive number.
16 . The method according to claim 13 , wherein determining each of the voltage levels of the power voltage and the initialization voltage includes:
determining the voltage level of the power voltage based on a first lookup table,
determining a voltage level of a first initialization voltage for initializing a gate electrode of a driving transistor included in the pixel among the initialization voltage based on a second lookup table, and
determining a voltage level of a second initialization voltage for initializing an anode electrode of a light emitting element included in the pixel among the initialization voltage based on a third lookup table.
17 . The method according to claim 13 , further comprising:
generating the power voltage and the initialization voltage based on the determined voltage levels; and
displaying an image on a display unit of the display device based on the generated power voltage and initialization voltage.
18 . The method according to claim 13 , wherein;
the first initialization voltage is a voltage for initializing a gate electrode of a driving transistor included in the pixel, the second initialization voltage is a voltage for initializing an anode electrode of a light emitting element included in the pixel, and the power voltage is supplied to a cathode electrode of the light emitting element included in the pixel; and
the first type transistor is a P-type transistor, the second type transistor is an N-type transistor, the voltage level of the first low voltage is a voltage level for turning on the P-type transistor, and the voltage level of the second low voltage is a voltage level for turning off the N-type transistor.