GOA Scan Driving Circuit Pull-Up Control Assembly Leakage Reduction
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Solution Overview
Problem
In typical gate driver on array (GOA) circuits, current leakage occurs due to residual charge causing the current scanning line to be driven even when inactive, affecting the stability and reliability of the GOA circuit.
Innovation Solution
The proposed scan driving circuit employs a pull-up assembly with a pull-up control assembly and a pull-down maintaining assembly, utilizing two reference low-level signals with different electric potentials to maintain the pull-up assembly in a negative turn-off status, reducing current leakage by ensuring the voltage difference between the control and output ends is less than zero, and using a diverter switch to balance electric potentials and prevent long-term work of single assemblies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a typical pull-up control assembly is used in the GOA circuit, then the current scanning line can be driven during active stage, but current leakage occurs during inactive stage due to residual charge causing voltage difference greater than zero
Solution Approach 1:
The patent segments the pull-down function into two separate assemblies: a first pull-down maintaining assembly connected to the control end and a second pull-down maintaining assembly connected to the output end. This segmentation allows independent control of the voltage at the control end and output end, enabling the voltage difference to be maintained below zero even when the scanning line is inactive, thus preventing current leakage while maintaining driving capability during active stages
Solution Approach 2:
The patent introduces a pull-down maintaining signal as an intermediary control signal that specifically targets the pull-down maintaining assemblies. This signal acts as a mediator to actively manage the voltage levels at the control end and output end, ensuring that the voltage difference remains negative during inactive stages to prevent residual charge from causing unwanted conduction, while allowing normal driving operation during active stages
2Reliability
If the pull-down maintaining assembly continuously works to maintain negative voltage difference, then current leakage is reduced, but the assembly may fail due to long-term continuous operation
Solution Approach 1:
The patent implements periodic action by having the first and second pull-down maintaining assemblies alternately work. During inactive stages, one assembly is activated while the other is in standby, and they switch roles periodically. This periodic alternation reduces the cumulative operating stress on each individual assembly, extending their service life while maintaining continuous protection against current leakage through the coordinated operation of both assemblies
Data Source
AI summary
A scan driving circuit includes a pull-up assembly, a pull-up control assembly that drives the pull-up assembly, a pull-down maintaining assembly, and a reference low-level signal. The reference low-level signal includes a first reference low-level signal and a second reference low-level signal. When the current scanning line is inactive, the pull-down maintaining assembly controls the reference low-level to be sent to the current scanning line and the output end of the pull-up control assembly according to a pull-down maintaining signal.