Gate Driving Compensation Circuit for Leakage Current in Display Devices

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Solution Overview

Problem

In display devices, the potential at the pull-up node of a gate driving unit is pulled down due to leakage current during touch stages, affecting the output of gate driving signals, especially at low-frequency outputs, leading to display issues.

Innovation Solution

A compensation circuit is introduced, including a touch ending signal input end, a pull-up input end, and a pull-up node voltage output end, with a pull-up control node control sub-circuit, a pull-up control storage capacitor sub-circuit, and a compensation sub-circuit, which controls the potential at the pull-up node to maintain and compensate for the voltage during touch stages, ensuring normal gate driving signal output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a touch stage is provided between two display stages for touch scanning operation, then touch operation can be performed, but the potential at the pull-up node of the gate driving unit is pulled down due to leakage current during the touch stage

Engineering Contradiction:

Improvetouch operation capabilityVSAvoidgate driving signal output stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The compensation circuit is activated in advance during the touch stage to preemptively counteract the leakage current effect. By detecting the touch stage timing and enabling the compensation circuit beforehand, the potential at the pull-up node is maintained before significant voltage drop occurs, ensuring stable gate driving signal output when display scanning resumes

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The compensation circuit uses the touch ending signal as feedback to detect when the touch stage occurs and when it ends. Based on this feedback information, the circuit dynamically adjusts its operation - activating during touch stage to compensate for leakage current, and deactivating when touch stage ends - thereby maintaining potential stability while enabling touch functionality

Inventive Principle:

Principle #23Feedback

2Productivity

If the touch stage is maintained for a relatively long time period, then touch scanning operation can be completed, but the potential at the pull-up node decreases gradually due to leakage current

Engineering Contradiction:

Improvetouch scanning completionVSAvoidpotential stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The touch ending signal provides feedback about the duration and timing of the touch stage. The compensation circuit uses this feedback to activate during the extended touch stage period, continuously compensating for leakage current effects throughout the entire touch scanning operation, and deactivates when the touch stage completes

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If the potential at the pull-up node is pulled down, then the touch stage operation is enabled, but the output of the gate driving signal is adversely affected

Engineering Contradiction:

Improvetouch stage operationVSAvoidgate driving signal output

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The compensation circuit acts as an intermediary between the touch stage operation and the gate driving unit. It detects when touch stage occurs and injects compensating current to counteract the leakage effect, thereby protecting the gate driving unit's pull-up node potential from being adversely affected while still allowing touch operation to proceed

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The touch ending signal serves as feedback to indicate when touch stage operation is occurring. The compensation circuit responds to this feedback by activating its compensation function to maintain potential stability, and stops compensation when the feedback indicates touch stage has ended

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS10725579B2Compensation circuit, gate driving unit, gate driving circuit, driving methods thereof and display device

Publication Date: 2020.07.28 BOE TECHNOLOGY GROUP CO LTD

AI summary

A compensation circuit, a gate driving unit, a gate driving method, driving method thereof, and a display device are provided. The compensation circuit includes: a pull-up control node control sub-circuit configured to control a touch ending signal input end to input a touch ending signal to a pull-up control node under the control of a pull-up input end; a pull-up control storage capacitor sub-circuit, a first end of which is connected to the pull-up input end, and a second end of which is connected to the pull-up control node; and a compensation sub-circuit configured to enable the pull-up control node to be electrically connected to the pull-up node voltage output end under the control of the pull-up control node.