Shift Register Unit for Gate Driving Circuit Leakage Reduction
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Solution Overview
Problem
Existing gate driving circuits face issues with electric leakage in oxide thin film transistors and weak output voltage loading capacity due to cascaded connections, and they struggle to effectively store pulse signals from previous stages, affecting the output of gate driving signals.
Innovation Solution
A shift register unit with an input reset circuit, storage node potential maintaining circuits, pull-up and pull-down node control circuits, and a gate driving output circuit, which includes capacitors and transistors to control node potentials and store pulse signals, ensuring adjustable pulse width and reduced leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If cascade connection is used to extend gate driving circuit, then the driving capability is improved, but the output voltage loading capacity becomes weak
Solution Approach 1:
The gate driving circuit is divided into multiple independent shift register units, each capable of driving its own load. This segmentation allows each unit to maintain sufficient output voltage loading capacity while the overall system achieves extended driving capability through serial connection of multiple units.
Solution Approach 2:
Instead of extending the circuit in a single cascade dimension which degrades voltage, the patent introduces a new dimension by adding bootstrap circuits that actively replenish voltage. This transforms the problem from a one-dimensional voltage degradation issue to a multi-dimensional solution involving both spatial distribution and temporal voltage restoration.
2Ease of manufacture
If oxide thin film transistor is used, then the integration is improved, but electric leakage occurs
Solution Approach 1:
The patent implements feedback mechanisms through bootstrap circuits that continuously monitor and compensate for voltage losses due to leakage. The circuits detect voltage droop caused by oxide TFT leakage and actively restore the voltage, creating a closed-loop system that mitigates leakage effects while maintaining the integration benefits of oxide TFTs.
Solution Approach 2:
The bootstrap circuits perform preliminary voltage restoration before the leakage completely degrades the signal. By anticipating and compensating for leakage effects in advance, the system maintains stable operation despite using oxide TFTs with inherent leakage characteristics.
3Device complexity
If pulse signal storage is not effective, then the circuit simplicity is maintained, but the gate driving signal output is affected
Solution Approach 1:
The patent merges the storage function into the existing shift register unit structure by utilizing the interstage coupling capacitors and node potentials already present in the circuit. This integration adds reliable pulse signal storage capability without requiring separate dedicated storage circuits, thus maintaining relative circuit simplicity while improving signal output reliability.
Data Source
AI summary
A shift register unit, a driving method, a gate driving circuit, and a display device are provided. The shift register unit includes an input reset circuit; a first storage node potential maintaining circuit; a second storage node potential control circuit; a pull-up node control circuit for controlling the potential of the pull-up node to be a valid level under the control of the second storage node, the second clock signal input end, and the fourth clock signal input end, and controlling to connect or disconnect the pull-up node and the second voltage input end under the control of the second clock signal input end and the third clock signal input end; a pull-up node potential maintaining circuit; a pull-down node control circuit; and a gate driving output circuit.