Gate Driver On Array Circuit Voltage Leakage Stabilization
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Solution Overview
Problem
Conventional gate driver on array (GOA) circuits in LCDs face issues with electricity leakage at the Q node, leading to incomplete scanning signal pulses due to capacitor charge leakage, which affects the output transistor's ability to conduct high voltage levels.
Innovation Solution
The proposed GOA circuit incorporates a holding module with transistors that form a direct current passage to maintain voltage levels, replacing capacitors, and includes a pull-up and pull-down module to ensure stable voltage levels, preventing electricity leakage and ensuring complete scanning signal pulses are produced.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a capacitor is used to store the Q node voltage to maintain high voltage level, then the voltage can be kept for at least a pulse of two hours, but the charge stored in the capacitor tends to leak from other transistors causing electricity leakage
Solution Approach 1:
The patent changes the voltage holding mechanism from capacitor-based to transistor-based. Specifically, it uses a first transistor configured in a specific circuit arrangement where the gate is connected to a control signal line, the source is connected to a power supply voltage line, and the drain is connected to the Q node. This transistor parameter configuration allows the Q node voltage to be maintained at a high level without the leakage problems inherent in capacitor-based storage, as the transistor's channel can be precisely controlled to prevent charge leakage while maintaining the required voltage duration.
2Reliability
If the Q node voltage is lowered due to electricity leakage, then the output transistor fails to be turned on completely, but maintaining high voltage level is necessary for complete conduction of signal at high voltage level
Solution Approach 1:
The patent employs multiple transistors with specific parameter configurations to maintain the Q node voltage at the required high level. The first transistor's gate, source, and drain are connected to specific lines to enable proper voltage maintenance. Additionally, a second transistor is configured with its gate connected to the Q node, source to the drain of the first transistor, and drain to a scanning signal line. This transistor-based voltage maintenance system ensures reliable output transistor conduction by preventing the voltage drop that would otherwise occur due to capacitor leakage, thereby ensuring complete signal conduction at high voltage levels.
Solution Approach 2:
The patent introduces control signal lines and power supply voltage lines as intermediaries between the transistors and the Q node. These intermediary connections allow precise control of the transistor operations and enable the maintenance of stable high voltage levels at the Q node without direct reliance on capacitor storage. The intermediaries facilitate the transfer of control signals and power while isolating the Q node from leakage paths, thereby ensuring reliable output transistor activation.
Data Source
AI summary
A GOA circuit includes GOA circuit units. A holding module is substituted for a capacitor in each GOA circuit unit. A second transistor in the holding module is turned on when a scanning signal does not produce a pulse so that voltage imposed in a first control node is held by a first transistor and a third transistor. Because the transistors form a passage between the first control node and a first constant voltage, the voltage imposed on the first control node does not vary due to electricity leakage. Because a second capacitor is coupled with the first control node, the pulse of the scanning signal output by the GOA circuit unit reaches to an ideal high voltage level. The GOA circuit unit can resolve the problem of easy leakage of electricity. When the scanning signals are output by the GOA circuit unit, the stability is highly ensured.