Display having rush current reduction during power-on
View Patent ↗A display that has rush current reduction during power-on is provided. A display panel that displays an image includes a gate line and a data line. A voltage generator receives a supply voltage and outputs a gate-on voltage and a gate-off voltage to first and second output nodes, respectively. The voltage generator includes a pull-up capacitor that is charged for a first time period of a power-off period and is discharged for a second time period of the power-off period to increase a voltage level of the second output node, the first and second time periods being consecutive periods of the power-off period. A gate driver selectively applies a gate-on voltage or a gate-off voltage to the gate lines, and a data driver applies a data voltage to the data line.
1. A display device comprising:
a display panel that displays an image and comprises a gate line and a data line;
a voltage generator that receives a supply voltage and outputs a gate-on voltage to a first output node and a gate-off voltage to a second output node, the voltage generator comprising a pull-up capacitor that is charged when the supply voltage is lower than a first voltage in a power-off period and is discharged when the supply voltage is lower than a second voltage in the power-off period to increase a voltage level of the second output node; and
a data driver that applies a data voltage to the data line,
wherein a voltage level of the second voltage is lower than a voltage level of the first voltage.
2. The display device of claim 1 , wherein the voltage generator further comprises:
a first switch that is enabled for the first time period and that transmits the gate-on voltage to the pull-up capacitor to charge the pull-up capacitor; and
a second switch that is enabled for the second time period and that transmits the voltage charged in the pull-up capacitor to the second output node.
3. The display device of claim 2 , wherein the first switch transmits the gate-on voltage to the pull-up capacitor according to the supply voltage, and the second switch transmits the voltage charged in the pull-up capacitor to the second output node according to the gate-on voltage.
4. The display device of claim 3 , wherein the first switch comprises an NPN bipolar junction transistor, and the second switch comprises a PNP bipolar junction transistor.
5. The display device of claim 2 , wherein when the supply voltage is lower than a first voltage, the first switch is enabled to transmit the gate-on voltage to the pull-up capacitor, and when the supply voltage is lower than a second voltage, the second switch transmits the voltage charged in the pull-up capacitor to the second output node.
6. The display device of claim 1 , wherein the voltage generator further outputs a drive voltage based upon the supply voltage, the gate-on voltage is generated based upon the drive voltage, and the voltage generator further comprises:
a first switch that is enabled for the first time period and that transmits the gate-on voltage to the pull-up capacitor to charge the pull-up capacitor; and
a second switch that is enabled for the second time period and that transmits the voltage charged in the pull-up capacitor to the second output node.
7. The display device of claim 6 , wherein the first switch transmits the gate-on voltage to the pull-up capacitor according to the drive voltage, and the second switch transmits the voltage charged in the pull-up capacitor to the second output node according to the gate-on voltage.
8. The display device of claim 6 , wherein:
when the drive voltage is lower than a first voltage, the first switch is enabled to transmit the gate-on voltage to the pull-up capacitor, and
when the drive voltage is lower than a second voltage, the second switch transmits the voltage charged in the pull-up capacitor to the second output node, a voltage level of the second voltage being lower than that of the first voltage.
9. The display device of claim 1 , wherein the voltage generator further comprises:
a gate-off voltage generator that generates the gate-off voltage; and
a gate-off voltage blocking portion that blocks a current path from the second output node to the gate-off voltage generator during the power-off period.
10. The display device of claim 1 , wherein the display panel further comprises a switching element that selectively connects the data line to a pixel electrode line according to the gate-on voltage or the gate-off voltage, the switching element being turned on for the second time period.
11. The display device of claim 1 , further comprising:
a display panel that displays an image and comprises a gate line and a data line;
a gate driver that selectively applies the gate-on voltage or the gate-off voltage to the gate lines; and
a data driver that applies a data voltage to the data line,
wherein the pull-up capacitor is charged for a first time period of the power-off period and is discharged for a second time period of the power-off period.
12. A display device comprising:
a display panel that displays an image and comprises a gate line and a data line; and
a voltage generator that comprises:
a pull-up capacitor;
a first switch that is connected to a first voltage and a second voltage and that selectively charges the pull-up capacitor using the second voltage according to the first voltage; and
a second switch that selectively transmits the voltage charged in the pull-up capacitor to the gate-off voltage output node,
wherein the first switch is enabled for a first time period of a power-off period, and the second switch is enabled for a second time period of the power-off period, the first time period and the second time period being consecutive periods of the power-off period,
wherein the voltage generator further comprises a gate-on voltage generator that generates a gate-on voltage based upon a supply voltage, the first voltage being the supply voltage and the second voltage being the gate-on voltage, and
wherein when the supply voltage is lower than a first voltage, the first switch is enabled to transmit the gate-on voltage to the pull-up capacitor, and when the supply voltage is lower than a second voltage, the second switch is enabled to transmit the voltage charged in the pull-up capacitor to the gate-off voltage output node, a voltage level of the second voltage being lower than a voltage level of the first voltage.
13. A display device comprising:
a display panel that displays an image and comprises a gate line and a data line; and
a voltage generator that comprises:
a pull-up capacitor;
a first switch that is connected to a first voltage and a second voltage and that selectively charges the pull-up capacitor using the second voltage according to the first voltage; and
a second switch that selectively transmits the voltage charged in the pull-up capacitor to the gate-off voltage output node,
wherein the first switch is enabled for a first time period of a power-off period, and the second switch is enabled for a second time period of the power-off period, the first time period and the second time period being consecutive periods of the power-off period,
wherein the voltage generator further comprises a drive voltage generator that generates a drive voltage based upon the supply voltage, and a gate-on voltage generator that generates the gate-on voltage based upon the drive voltage, the first voltage being the drive voltage and the second voltage being the gate-on voltage, and
wherein when the drive voltage is lower than the first voltage, the first switch is enabled to transmit the gate-on voltage to the pull-up capacitor, and when the drive voltage is lower than the second voltage, the second switch is enabled to transmit the voltage charged in the pull-up capacitor to the gate-off voltage output node, a voltage level of the second voltage being lower than that of the first voltage.