Shift Register Unit for GOA Circuit Noise Reduction
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Solution Overview
Problem
The existing Gate Driver on Array (GOA) circuits in Liquid Crystal Displays (LCDs) suffer from high output noise due to unreleased coupling capacitance, which affects the stability of the gate drive circuit.
Innovation Solution
A shift register unit comprising a pull-up control module, a reset module, an output module, a first control module, and a second control module, connected in a specific configuration to manage voltage and signal inputs, thereby reducing noise by releasing coupling capacitance and stabilizing output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If drive transistors are made large in size to handle higher current, then the driving capability is improved, but the coupling capacitance increases causing high output noise
Solution Approach 1:
The patent extracts the harmful coupling capacitance from the drive circuit by adding a dedicated discharge path through the discharge transistor. This separates the driving function (performed by the large drive transistor) from the capacitance discharge function, allowing the drive transistor to maintain its large size for high driving capability while the discharge transistor actively removes the harmful capacitance to reduce output noise.
2Device complexity
If the coupling capacitance is not fully released, then the circuit operation is simplified, but the output noise increases and stability decreases
Solution Approach 1:
The patent implements a feedback mechanism where the discharge transistor is controlled by a discharge control signal that activates when needed to remove coupling capacitance. This feedback-based discharge control ensures the capacitance is released at appropriate moments, maintaining output stability without requiring complex continuous discharge circuits, thus balancing simplicity and reliability.
Data Source
AI summary
The present invention provides a shift register unit and its driving method, a gate drive circuit and a display device, which can at least partially alleviate the problem of noise interference caused by non-release of the coupling capacitance of the thin film transistor itself in the GOA circuit. The shift register unit comprises: a pull-up control module for transmitting voltage of a first voltage terminal to a pull-up control node under the control of a first signal input terminal; a reset module for pulling down the potential of said pull-up control node to a voltage of a second voltage terminal under the control of a second signal input terminal; an output module for transmitting a signal input through a first clock signal terminal to a signal output terminal under the control of said pull-up control node; a first control module for pulling down the potential of the signal output terminal to the voltage of the second voltage terminal under the control of a second clock signal terminal; a second control module for pulling up or down the potential of the pull-up control node to a voltage of the first signal input terminal under the control of the second clock signal terminal.