Gate Driver Scan Signal Falling Time Reduction
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Solution Overview
Problem
In display devices, the overlapping of scan signals across different gate lines leads to inaccurate data voltage writing to pixels, resulting in inefficiencies and defects due to the inability to accurately manage the falling time of scan signals.
Innovation Solution
A gate driver is designed with stages that include specific transistors and capacitors to control the voltage of nodes, outputting scan signals efficiently by applying a low power voltage to the output terminal in response to carry signals, thereby reducing the falling time of scan signals and minimizing overlapping times across gate lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional gate driver outputs scan signals to gate lines, then the display device can perform scanning operations, but the scan signals overlap across different gate lines causing inaccurate data voltage writing
Solution Approach 1:
The patent applies preliminary action by proactively reducing the falling time of scan signals through optimized transistor switching sequences and voltage control. The gate driver circuit is designed to preemptively manage the discharge path of capacitive loads, ensuring that scan signals transition to low state faster before overlapping occurs, thereby preventing data writing errors at pixel electrodes.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting voltage levels and switching timing parameters in the gate driver circuit. By modifying the discharge voltage potential and controlling the switching timing of transistors (such as using different low power voltages for different discharge paths), the falling time of scan signals is reduced, which resolves the overlap issue and improves data writing accuracy.
2Loss of time
If the gate driver uses a simple output structure, then the device complexity is reduced, but the falling time of scan signals increases causing signal overlap
Solution Approach 1:
The patent applies segmentation by dividing the gate driver output structure into multiple independent transistor stages and separate discharge paths. Instead of a single complex switching element, the circuit uses segmented transistor networks (including multiple NMOS and PMOS transistors arranged in specific configurations) that can independently control different aspects of the scan signal transition, thereby reducing falling time without creating an uncontrollably complex structure.
Solution Approach 2:
The patent introduces intermediary elements such as additional transistors and capacitors that act as mediators in the signal transmission path. These intermediary components facilitate faster voltage transitions by providing dedicated discharge paths and controlling the rate of change of voltages at critical nodes, thus reducing scan signal falling time while maintaining a manageable circuit complexity through modular design.
Data Source
AI summary
A gate driver includes stages. Each stage includes: a first output part for outputting a carry signal in response to a voltage of a first node; a first input part for controlling the voltage of the first node in response to a previous carry signal; a second input part for controlling the voltage of the first node in response to a first next carry signal; a second output part for outputting a scan signal in response to the voltage of the first node; a third output part for outputting a sensing signal in response to the voltage of the first node; and a scan signal control part for applying a first low power voltage to an output terminal of the second output part to which the scan signal is output in response to a second next carry signal of which a pulse is generated before the first next carry signal.


