Gate Driving Circuit Kink Current Suppression

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Solution Overview

Problem

Current gate driving circuits face challenges in achieving superior driving characteristics and improved display quality due to issues such as delayed gate signal transmission and kink current caused by band-to-band tunneling phenomena, which affect the charge rate of pixels and result in horizontal line artifacts on display panels.

Innovation Solution

The proposed gate driving circuit incorporates a configuration of stages with specific voltage input terminals and control transistors that manage clock and carry signals to control the operation of output transistors, reducing kink current by applying a reference voltage to control electrodes, thereby stabilizing the electric potential and preventing late switching of output transistors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional gate driving circuits are used, then the circuit structure is simple, but delayed gate signal transmission and kink current occur causing horizontal line artifacts

Engineering Contradiction:
Improvegate signal transmission accuracyVSAvoidcircuit structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The gate driving circuit is divided into multiple stages, with each stage independently controlling a segment of gate lines. Each stage includes separate first and second output parts that independently drive different gate line segments, preventing error propagation and reducing kink current effects across the entire display panel.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A compensation transistor is introduced as an intermediary element between the output transistor and the gate line. This compensation transistor specifically suppresses kink current by controlling the flow of current through the pixel transistor, thereby eliminating horizontal line artifacts without requiring major structural changes to the existing circuit.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If output transistors switch late due to kink current, then display quality deteriorates with horizontal line artifacts, but changing the switching timing may cause other signal transmission issues

Engineering Contradiction:
Improvepixel charge rateVSAvoidsignal transmission stability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The circuit applies a reference voltage to the control electrode of the output transistor in advance before the actual switching operation. This preliminary voltage application ensures that the output transistor switches at the correct timing without being affected by kink current, thereby preventing horizontal line artifacts while maintaining stable signal transmission.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the voltage parameter applied to the control electrode by introducing a reference voltage terminal. This parameter change ensures that the control electrode maintains a stable electric potential throughout the switching process, preventing delayed switching and ensuring consistent pixel charging across all gate lines.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If reference voltage is applied to control electrodes to prevent late switching, then timing accuracy improves, but circuit complexity increases

Engineering Contradiction:
Improvegate signal timing accuracyVSAvoidvoltage input terminals
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The reference voltage terminal serves multiple functions: it prevents late switching of output transistors, suppresses kink current, and ensures stable electric potential at control electrodes. By making this single terminal multi-functional, the invention achieves improved timing accuracy without proportionally increasing circuit complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The reference voltage is applied specifically to the control electrodes of output transistors that are prone to late switching, rather than uniformly to all control electrodes in the circuit. This localized application of reference voltage targets the specific problem area, improving timing accuracy where needed while minimizing the overall increase in circuit complexity.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration enhances the timing accuracy of gate signals, reduces kink current, and improves the charge rate of pixels, leading to better display quality by minimizing horizontal line artifacts and ensuring consistent signal transmission across the display panel.

Implementation Method 1

a second signal for controlling a threshold voltage of the first and the second transistor is inputted to the second gate

Methodology Applied
Scientific EffectThreshold voltage control:

Implementation Method 2

a current which flows between sources and drains of the first and second transistor

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

insulating layers provided therebetween

Methodology Applied
Scientific EffectElectrical insulation: Electrical Resistance

Data Source

PatentEP2701203B1Gate driving circuit and display apparatus having the same
Publication Date: 2017.04.05 SAMSUNG DISPLAY CO LTD
  • EP2701203B1 patent drawingFigure 1
  • EP2701203B1 patent drawingFigure 2
  • EP2701203B1 patent drawingFigure 3

AI summary

A display apparatus including a gate driving circuit configured to include a plurality of stages connected to each other one after another. An i-th stage of the stages includes an output transistor and a control part. At least one control transistor included in the control part includes a first control electrode to which a switching control signal is applied, and a second control electrode disposed on a layer different from a layer on which the first control electrode is disposed, and to which a reference voltage is applied.