GOA Circuit Compensation Control for TFT Threshold Voltage Stability
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Solution Overview
Problem
TFTs in the GOA circuit are subjected to electrical stress from Vgs and Vds, causing the threshold voltage to be easily biased, which leads to a decrease in output capacity.
Innovation Solution
A GOA circuit comprising cascaded units with a pull-up control unit, a pull-up unit, a compensation control unit, and a pull-down unit, where the compensation control unit stores the threshold voltage of the thin film transistor in a capacitor, ensuring stable output by managing the potential of the scanning signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TFTs in the GOA circuit are subjected to electrical stress from Vgs and Vds, then the circuit can operate, but the threshold voltage becomes easily biased, leading to decreased output capacity
Solution Approach 1:
The patent applies preliminary action by pre-charging the horizontal scanning line before the TFT switches are turned on. The pull-up unit charges the gate line to a high potential in advance, so when the TFTs switch on, they operate under more stable electrical conditions with reduced stress, preventing threshold voltage bias before it occurs
Solution Approach 2:
The patent introduces an intermediary mechanism through the pull-up and pull-down units that mediate the electrical stress on TFTs. These units control the charging and discharging of the gate line, acting as intermediaries between the power supply and the TFTs, thereby reducing direct electrical stress and preventing threshold voltage bias
2Area of stationary object
If GOA technology is used to replace external IC, then border line density is reduced and space is saved, but TFTs become more susceptible to electrical stress effects
Solution Approach 1:
The patent applies segmentation by dividing the gate driver functionality into separate pull-up and pull-down units within the GOA circuit. This segmentation allows independent control of charging and discharging operations, enabling better management of electrical stress on TFTs while maintaining the space-saving benefits of integrated GOA design
Solution Approach 2:
The patent utilizes parameter changes by dynamically adjusting the potential of the horizontal scanning line through controlled charging and discharging cycles. The pull-up unit raises the potential to reduce electrical stress on TFTs during operation, while the pull-down unit resets the potential afterward, maintaining stability without requiring additional external components
Data Source
AI summary
Gate Driver on Array (GOA) circuit and display device solving problem of electrical stress easily biasing threshold voltage of thin film transistor (TFT), are provided. The GOA circuit including m cascaded GOA units, wherein an nth GOA unit includes a pull-up control unit, a pull-up unit, a compensation control unit, and a pull-down unit.