GOA Circuit Third Node Voltage Control
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Solution Overview
Problem
The existing gate driver on array (GOA) circuits experience threshold voltage shift due to the third node staying at a high level for an extended period, leading to reduced stability and abnormal output.
Innovation Solution
The proposed GOA circuit uses the ninth and tenth TFTs and a resistor to control the voltage level of the third node, with the ninth TFT connected to the m-th clock signal and the tenth TFT connected to the (m+2)-th clock signal, alternately becoming conductive to charge and discharge the third node regularly, preventing threshold voltage shift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the third node stays at high level for extended period, then the GOA circuit can maintain output state, but threshold voltage shift occurs leading to reduced stability
Solution Approach 1:
The patent applies periodic action by using clock signals to periodically switch the ninth and tenth TFTs, which regularly charge and discharge the third node. This periodic switching prevents the third node from staying at high level for extended periods, thereby avoiding threshold voltage shift and maintaining circuit stability while still allowing adequate output duration.
2Duration of action of moving object
If the fourth TFT and seventh TFT stay conductive for extended period, then the circuit maintains functionality, but threshold voltage shift occurs
Solution Approach 1:
The patent uses periodic clock signals to control the switching of the ninth and tenth TFTs, which in turn periodically adjust the conduction state of the fourth and seventh TFTs. This periodic control ensures these TFTs do not remain conductive for excessively long periods, preventing threshold voltage shift while maintaining necessary functionality.
3Reliability
If the third node is regularly charged and discharged, then threshold voltage shift is prevented, but additional TFTs and control circuitry are required
Solution Approach 1:
The patent achieves multi-functionality by using the clock signals that already exist in the GOA circuit to also control the charging and discharging of the third node. The ninth and tenth TFTs are integrated into the existing circuit architecture, allowing the clock signals to serve dual purposes: driving the scan operation and regulating the third node voltage, thereby minimizing additional complexity.
Data Source
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AI summary
The invention provides a GOA circuit, using the ninth and tenth TFTs and the resistor to control the voltage level of the third node, wherein ninth TFT having the gate connected to the m-th clock signal, the source connected to the first constant voltage, and the drain connected to one end of the resistor; the tenth TFT having the gate connected to the (m+2)-th clock signal, the source connected to the second constant voltage, and the drain connected to the other end of the resistor. Through the m-th and the (m+2)-th clock signal to control the ninth and the tenth TFTs to become conductive alternately, the present invention can charge and discharge the third node regularly to prevent the threshold voltage shift of the key TFT because the third node stays high for extended time, and ensure the stability of GOA circuit.