Gate drive circuit and display device using the same

Patent metadata

Field	Value
Publication number	US-10019929-B2
Application number	US-201514983736-A
Country	US
Kind code	B2
Filing date	Dec 30, 2015
Priority date	Jul 31, 2015
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

A display device having a plurality of gate lines and a gate drive circuit is disclosed. The gate drive circuit includes a pull-up transistor configured to receive a first clock signal and to charge an output node to a voltage of the first clock signal based on a voltage of a Q node. The output node is connected to a corresponding one of the gate lines. The gate drive circuit also includes a switching circuit configured to charge the Q node based on a second clock signal. The switching circuit has an inverter circuit configured to control the voltage of the Q node based on the second clock signal.

First claim

What is claimed is:

1. A gate drive circuit for a display device having a plurality of gate lines, the gate drive circuit comprising:
a pull-up transistor configured to charge an output node to a voltage of a first clock signal based on a voltage of a Q node, the pull-up transistor having a gate connected to the Q node, a drain configured to receive the first clock signal, and a source connected to the output node, the output node being connected to a corresponding one of the gate lines;
an inverter circuit configured to control the voltage of the Q node based on a second clock signal received via an inverter input node, the inverter circuit including:
a first transistor having a gate configured to receive the second clock signal via the inverter input node, a drain connected to the Q node, and a source configured to receive a first low-potential voltage, and
a second transistor having a drain connected to the inverter input node, a gate connected to the Q node, and a source configured to receive the first low-potential voltage;

a third transistor having a gate configured to receive a third clock signal, a drain connected to the inverter input node, and a source configured to receive the first low-potential voltage; and
a pull-down transistor configured to discharge a voltage of the output node to the first low-potential voltage in response to a fourth clock signal, the pull-down transistor having a gate configured to receive the fourth clock signal, a drain connected to the output node, and a source configured to receive the first low-potential voltage,
wherein phases of the first to the fourth clock signals are sequentially delayed in order of the second clock signal, the first clock signal, the third clock signal and the fourth clock signal.

2. The gate drive circuit of claim 1 , further comprising a capacitor configured to receive the second clock signal and provide the second clock signal to the inverter input node.

3. The gate drive circuit of claim 1 , further comprising a diode configured to receive the second clock signal and provide the second clock signal to the inverter input node.

4. The gate drive circuit of claim 1 , wherein the gate of the pull-down transistor is configured to receive the fourth clock signal when the display device is powered on and is configured to receive a second low-potential voltage lower than the first low-potential voltage after the display device is powered off.

5. The gate drive circuit of claim 1 , wherein a gate-source voltage of the pull-down transistor is a positive voltage when the display device is powered on and is a negative voltage when the display device is powered off.

6. The gate drive circuit of claim 1 , further comprising:
a fourth transistor configured to supply an output voltage of a previous gate line to the Q node, the fourth transistor having a gate and a drain connected to an output node of the previous gate line and a source connected to the Q node; and
a fifth transistor configured to discharge the Q node in response to an output voltage of a next gate line, the fifth transistor having a gate connected to an output node of the next gate line, a drain connected to the Q node and a source connected to the first low-potential voltage.

7. A display device, comprising:
a display panel having data lines and gate lines intersecting each other and pixels arranged in a matrix form;
a timing controller configured to supply a first clock signal, a second clock signal, a third clock signal, and a fourth clock signal;
a data drive circuit configured to supply a data signal to the data lines; and
a gate drive circuit configured to supply a gate pulse synchronized with the data signal to the gate lines, the gate drive circuit including:
a pull-up transistor configured to charge an output node to a voltage of the first clock signal based on a voltage of a Q node, the pull-up transistor having a gate connected to the Q node, a drain configured to receive the first clock signal, and a source connected to the output node, the output node being connected to a corresponding one of the gate lines;
a pull-down transistor configured to discharge a voltage of the output node to a first low-potential voltage in response to the fourth clock signal, the pull-down transistor having a gate configured to receive the fourth clock signal, a drain connected to the output node, and a source configured to receive the first low-potential voltage;
an inverter circuit configured to control the voltage of the Q node based on the second clock signal received via an inverter input node, the inverter circuit including:
a first transistor having a gate configured to receive the second clock signal via the inverter input node, a drain connected to the Q node, and a source configured to receive the first low-potential voltage, and
a second transistor having a drain connected to the inverter input node, a gate connected to the Q node, and a source configured to receive the first low-potential voltage; and

a third transistor having a gate configured to receive the third clock signal, a drain connected to the inverter input node, and a source configured to receive the first low-potential voltage,

wherein phases of the first to the fourth clock signals are sequentially delayed in order of the second clock signal, the first clock signal, the third clock signal and the fourth clock signal.

8. The display device of claim 7 , wherein the gate drive circuit further includes a capacitor configured to receive the second clock signal and provide the second clock signal to the inverter input node.

9. The display device of claim 7 , wherein the gate drive circuit further includes a diode configured to receive the second clock signal and provide the second clock signal to the inverter input node.

10. The display device of claim 7 , further comprising an auxiliary power supply configured to drive the timing controller for a predetermined period of time after a power to the display device is turned off,
wherein the gate of the pull-down transistor is configured to receive the fourth clock signal when the power to the display device is turned on and is configured to receive a second low-potential voltage lower than the first low-potential voltage during the predetermined period of time after the power to the display is turned off.

11. The display device of claim 10 , wherein a gate-source voltage of the pull-down transistor is a positive voltage when the power to the display device is turned on and is a negative voltage during the predetermined period of time after the power to the display is turned off.

12. The display device of claim 7 , further comprising:
a fourth transistor configured to supply an output voltage of a previous gate line to the Q node, the fourth transistor having a gate and a drain connected to an output node of the previous gate line and a source connected to the Q node; and
a fifth transistor configured to discharge the Q node in response to an output voltage of a next gate line, the fifth transistor having a gate connected to an output node of the next gate line, a drain connected to the Q node and a source connected to the first low-potential voltage.

Assignees

• Lg Display Co Ltd

Inventors

• Shim Dahye
• Choi Joungmi
• Cho Youngsung
• Kim Jiah

Classifications

• G09G2310/0202

  Addressing of scan or signal lines · CPC title

• G09G2300/0426

  Layout of electrodes and connections · CPC title

• G09G2330/028

  Generation of voltages supplied to electrode drivers in a matrix display other than LCD · CPC title

• G09G2330/027

  Arrangements or methods related to powering off a display · CPC title

• G09G2310/0286

  Details of a shift registers arranged for use in a driving circuit · CPC title