Electrostatic discharge protection circuit and organic light emitting display device including the same

Patent metadata

Field	Value
Publication number	US-11127352-B2
Application number	US-202017103530-A
Country	US
Kind code	B2
Filing date	Nov 24, 2020
Priority date	Jan 16, 2020
Publication date	Sep 21, 2021
Grant date	Sep 21, 2021

Abstract

An electrostatic discharge protection circuit including: a first electrostatic discharge diode including a cathode to receive a first voltage, and an anode connected to a sensing line; a first switching element to determine the first voltage as a precharging voltage applied to a source terminal of the driving transistor when a sensing operation is performed, and to determine the first voltage as a maximum voltage used in a display panel when the sensing operation is not performed; a second electrostatic discharge diode including a cathode connected to the sensing line, and an anode configured to receive a second voltage; and a second switching element configured to determine the second voltage as the precharging voltage when the sensing operation is performed, and to determine the second voltage as a minimum voltage used in the display panel when the sensing operation is not performed.

First claim

What is claimed is:

1. An electrostatic discharge protection circuit comprising:
a first electrostatic discharge diode including a cathode configured to receive a first voltage, and an anode connected to a sensing line through which a sensing current flows when a sensing operation for compensating for a characteristic deviation of a driving transistor of a pixel circuit is performed;
a first switching element configured to determine the first voltage as a precharging voltage applied to a source terminal of the driving transistor for the sensing operation when the sensing operation is performed, and to determine the first voltage as a maximum voltage used in a display panel when the sensing operation is not performed;
a second electrostatic discharge diode including a cathode connected to the sensing line, and an anode configured to receive a second voltage; and
a second switching element configured to determine the second voltage as the precharging voltage when the sensing operation is performed, and to determine the second voltage as a minimum voltage used in the display panel when the sensing operation is not performed.

2. The electrostatic discharge protection circuit of claim 1 , wherein the first electrostatic discharge diode and the second electrostatic discharge diode are located at the display panel.

3. The electrostatic discharge protection circuit of claim 1 , wherein the maximum voltage is a first gate driving voltage corresponding to a high voltage level of a gate signal, and the minimum voltage is a second gate driving voltage corresponding to a low voltage level of the gate signal.

4. The electrostatic discharge protection circuit of claim 1 , wherein, in response to a voltage of the sensing line being greater than the first voltage as an electrostatic discharge current is introduced into the sensing line when the sensing operation is not performed, the first electrostatic discharge diode is configured to discharge the electrostatic discharge current to a voltage line configured to supply the first voltage.

5. The electrostatic discharge protection circuit of claim 1 , wherein, in response to a voltage of the sensing line being less than the second voltage as an electrostatic discharge current is introduced into the sensing line when the sensing operation is not performed, the second electrostatic discharge diode is configured to discharge the electrostatic discharge current to a voltage line configured to supply the second voltage.

6. The electrostatic discharge protection circuit of claim 1 , further comprising:
a third electrostatic discharge diode including a cathode configured to receive an analog high voltage, and an anode connected to the sensing line; and
a fourth electrostatic discharge diode including a cathode connected to the sensing line, and an anode configured to receive an analog low voltage.

7. The electrostatic discharge protection circuit of claim 6 , wherein the third electrostatic discharge diode and the fourth electrostatic discharge diode are located at a display panel driving circuit configured to drive the display panel.

8. The electrostatic discharge protection circuit of claim 6 , wherein, in response to a voltage of the sensing line being greater than the first voltage as an electrostatic discharge current is introduced into the sensing line when the sensing operation is not performed, the third electrostatic discharge diode is configured to discharge the electrostatic discharge current to a voltage line configured to supply the analog high voltage.

9. The electrostatic discharge protection circuit of claim 6 , wherein, in response to a voltage of the sensing line being less than the second voltage as an electrostatic discharge current is introduced into the sensing line when the sensing operation is not performed, the fourth electrostatic discharge diode is configured to discharge the electrostatic discharge current to a voltage line configured to supply the analog low voltage.

10. An organic light emitting display device comprising:
a display panel comprising a pixel circuit including an organic light emitting diode;
a display panel driving circuit configured to drive the display panel; and
an electrostatic discharge protection circuit configured to protect the display panel from an electrostatic discharge current externally introduced, the electrostatic discharge protection circuit comprising:
a first electrostatic discharge diode including a cathode configured to receive a first voltage, and an anode connected to a sensing line through which a sensing current flows when a sensing operation for compensating for a characteristic deviation of a driving transistor of the pixel circuit is performed;
a first switching element configured to determine the first voltage as a precharging voltage applied to a source terminal of the driving transistor for the sensing operation when the sensing operation is performed, and to determine the first voltage as a maximum voltage used in the display panel when the sensing operation is not performed;
a second electrostatic discharge diode including a cathode connected to the sensing line, and an anode configured to receive a second voltage; and
a second switching element configured to determine the second voltage as the precharging voltage when the sensing operation is performed, and to determine the second voltage as a minimum voltage used in the display panel when the sensing operation is not performed.

11. The organic light emitting display device of claim 10 , wherein the pixel circuit comprises:
a switching transistor including a first terminal configured to receive a data signal, a second terminal connected to a first node, and a gate terminal configured to receive a gate signal;
a storage capacitor including a first terminal connected to the first node and a second terminal connected to a second node;
the driving transistor including a first terminal connected to a third node, a second terminal corresponding to the source terminal and connected to the second node, and a gate terminal connected to the first node;
an emission control transistor including a first terminal connected to a high power supply voltage line, a second terminal connected to the third node, and a gate terminal configured to receive an emission control signal;
a sensing control transistor including a first terminal connected to the second node, a second terminal connected to the sensing line, and a gate terminal configured to receive a sensing control signal; and
the organic light emitting diode including an anode connected to the second node and a cathode connected to a low power supply voltage line.

12. The organic light emitting display device of claim 11 , wherein the display panel driving circuit comprises:
a gate driver configured to provide the gate signal to the pixel circuit;
a data driver configured to provide the data signal to the pixel circuit;
an emission control driver configured to provide the emission control signal to the pixel circuit;
a sensing driver configured to receive the sensing current from the pixel circuit to generate a sensing voltage corresponding to the sensing current, and to generate compensation data for compensating the data signal based on the sensing voltage; and
a timing controller configured to control the gate driver, the data driver, the emission control driver, and the sensing driver.

13. The organic light emitting display device of claim 10 , wherein the first electrostatic discharge diode and the second electrostatic discharge diode are located at the display panel.

14. The organic light emitting display device of claim

Assignees

• Samsung Display Co Ltd

Inventors

• Kang Ho Cheol
• Kim Ha Neul
• Jang Dae-Gwang
• Hwang Young-Soo

Classifications

• G09G2320/029

  by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel · CPC title

• G09G2330/04

  Display protection · CPC title

• G09G3/3233 Primary

  with pixel circuitry controlling the current through the light-emitting element · CPC title

• G09G3/3258 Primary

  with pixel circuitry controlling the voltage across the light-emitting element · CPC title

• G09G2300/0814

  used for selection purposes, e.g. logical AND for partial update · CPC title