Gate driving circuit

Patent metadata

Field	Value
Publication number	US-10198987-B2
Application number	US-201715840927-A
Country	US
Kind code	B2
Filing date	Dec 13, 2017
Priority date	Dec 19, 2016
Publication date	Feb 5, 2019
Grant date	Feb 5, 2019

Abstract

The gate driving circuit includes a shift register including a plurality of stages. An n-th stage among the plurality of stages includes: a pull-up switching element outputting a first clock to an output node in accordance with a voltage in a Q node, a pull-down switching element outputting a gate low voltage VGL to the output node in accordance with a voltage in a QB node, and a logic unit inverting and outputting a voltage in the Q node and a voltage in the QB node. The logic unit includes a first switching element including a gate to which a fourth clock is input and being between a start voltage line which supplies a start voltage and the Q node, a second switching element including a gate connected to the Q node and being connected to the QB node, a third switching element being between the second switching element and a gate low voltage line which supplies the gate low voltage, a fourth switching element including a gate to which a third clock is input and being between a gate high voltage line which supplies a gate high voltage and the QB node, a fifth switching element including a gate connected to the QB node and being between the Q node and the gate low voltage line, a first capacitor between the Q node and the output node, and a second capacitor between the gate low voltage line and the gate of the pull-down switching element.

First claim

What is claimed is:

1. A gate driving circuit, comprising:
a shift register including a plurality of stages, the shift register configured to receive a first clock, a second clock, a third clock, and a fourth clock,
wherein an n-th stage (n is a positive integer) among the plurality of stages includes:
a pull-up switching element that outputs the first clock to an output node based on a voltage at a Q node;
a pull-down switching element that outputs a gate low voltage to the output node based on a voltage at a QB node; and
a logic unit that outputs the voltage at the Q node and the voltage at the QB node, the logic unit including:
a first switching element including a gate to which the fourth clock is input, the first switching element being connected between a start voltage line which supplies a start voltage to the logic unit and the Q node;
a second switching element connected to the QB node, the second switching element including a gate connected to the Q node;
a third switching element connected between the second switching element and a gate low voltage line which supplies the gate low voltage;
a fourth switching element including a gate to which the third clock is input, the fourth switching element being connected between a gate high voltage line which supplies a gate high voltage and the QB node;
a fifth switching element including a gate connected to the QB node, the fifth switching element being connected between the Q node and the gate low voltage line;
a first capacitor connected between the Q node and the output node; and
a second capacitor connected between the gate low voltage line and the gate of the pull-down switching element.

2. The gate driving circuit according to claim 1 , wherein the third switching element includes a gate connected to the Q node.

3. The gate driving circuit according to claim 2 , wherein when the voltage at the Q node is high, the second switching element and the third switching element supply the gate low voltage to the QB node.

4. The gate driving circuit according to claim 1 , wherein the third switching element includes a gate to which the fourth clock is input.

5. The gate driving circuit according to claim 4 , wherein when both the fourth clock and the start voltage are high, the second switching element and the third switching element supply the gate low voltage to the QB node.

6. The gate driving circuit according to claim 1 , wherein when both the start voltage supplied from the start voltage line and the fourth clock are high, the first switching element charges the Q node to be high.

7. The gate driving circuit according to claim 1 , wherein when the first clock is input in a high state while the voltage at the Q node is in a high state, the first capacitor raises the voltage at the Q node as the voltage in the output node rises.

8. The gate driving circuit according to claim 1 , wherein a n−1-th stage, which is a previous stage with respect to the n-th stage, includes a pull-up switching element that outputs the fourth clock to an output node of the n−1-th stage based on a voltage at a Q node of the n−1-th stage.

9. A gate driving circuit, comprising:
a shift register including a plurality of stages, the shift register configured to receive a first clock, a second clock, a third clock, and a fourth clock,
wherein an n-th stage (n is a positive integer) among the plurality of stages includes:
a pull-up switching element including a gate connected to a Q node, the pull-up switching element being connected between a first clock line which supplies the first clock and an output node;
a pull-down switching element including a gate connected to a QB node, the pull-down switching element being connected between a gate low voltage line which supplies a gate low voltage and the output node; and
a logic unit that outputs a voltage at the Q node and a voltage at the QB node, the logic unit including:
a first switching element including a gate to which a start voltage is input, the first switching element being connected between a gate high voltage line which supplies a gate high voltage and the Q node;
a second switching element connected to the QB node, the second switching element including a gate connected to the Q node;
a third switching element including a gate to which the third clock is input, the third switching element being connected between the gate high voltage line and the QB node;
a fourth switching element including a gate connected to the QB node, the fourth switching element being connected between the Q node and the gate low voltage line;
a first capacitor connected between the Q node and the output node; and
a second capacitor connected between the gate low voltage line and the gate of the pull-down switching element.

10. The gate driving circuit according to claim 9 , wherein when the start voltage is high, the first switching element charges the Q node to be high.

11. The gate driving circuit according to claim 9 , wherein when the first clock is input in a high state while the voltage at the Q node is in a high state, the first capacitor raises the voltage at the Q node as the voltage in the output node rises.

12. The gate driving circuit according to claim 9 , wherein a n+1-th stage, which is a next stage with respect to the n-th stage, includes a pull-up switching element that outputs the second clock to an output node of the n+1-th stage based on a voltage at a Q node of the n+1-th stage.

13. The gate driving circuit according to claim 9 , further comprising:
a fifth switching element including a gate to which the start voltage is input, the fifth switching element being connected between the second switching element and the gate low voltage line.

14. The gate driving circuit according to claim 13 , wherein when the start voltage is high, the first switching element charges the Q node to be high.

15. The gate driving circuit according to claim 13 , wherein when the first clock is input in a high state while the voltage at the Q node is in a high state, the first capacitor raises the voltage at the Q node as the voltage in the output node rises.

16. The gate driving circuit according to claim 13 , wherein a n+1-th stage, which is a next stage with respect to the n-th stage, includes a pull-up switching element that outputs the second clock to an output node of the n+1-th stage based on a voltage at a Q node of the n+1-th stage.

Assignees

• Lg Display Co Ltd

Inventors

• Shim Woosung
• Bong Junho

Classifications

• G11C19/28

  using semiconductor elements (G11C19/14, G11C19/36 take precedence) · CPC title

• G09G2310/0286

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

• H03K17/56

  by the use, as active elements, of semiconductor devices (using diodes H03K17/74) · CPC title

• G09G2300/0871

  with level shifting · CPC title

• G11C19/184

  with field-effect transistors, e.g. MOS-FET · CPC title