Shift Register Unit Pull-Up Node Discharge Control
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Solution Overview
Problem
The existing shift register units in display devices cannot completely discharge and denoise pull-up nodes in the non-output phase, leading to increased power consumption and size, which hinders the implementation of low power consumption and narrow frame requirements.
Innovation Solution
A shift register unit with a pull-up node control unit, a pull-down node control unit, and a carry signal output unit, which includes transistors to control electrical potentials and output signals, allowing for complete discharging and denoising of pull-up nodes in the non-output phase, and using the carry signal output terminal to provide input signals to adjacent stages instead of the gate driving signal output terminal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shift register unit uses a large transistor for outputting gate driving signal directly, then the input signal can be provided to the next stage, but the size and power consumption of the shift register unit increases
Solution Approach 1:
The patent segments the output function into two separate terminals: a gate driving signal output terminal for driving gate lines, and a carry signal output terminal for providing input signals to the next stage. This segmentation allows the transistor size to be optimized for each function separately, reducing the overall transistor size required while maintaining signal transmission reliability.
Solution Approach 2:
The carry signal output terminal serves multiple functions: it provides clock signals to the next stage during normal operation and can serve as a reset signal input during reset phases. This multi-functionality reduces the need for separate dedicated transistors for each function, thereby reducing power consumption and device size.
2Reliability
If the shift register unit uses a large transistor for outputting gate driving signal, then the input signal can be provided to the next stage, but the size of the shift register unit increases
Solution Approach 1:
The patent divides the output functionality into two separate terminals: the gate driving signal output terminal and the carry signal output terminal. This segmentation allows smaller transistors to be used for each function individually, reducing the overall device area while maintaining reliable signal transmission to the next stage.
3Device complexity
If the pull-up node is not completely discharged in non-output phase, then the circuit operation is simplified, but power consumption increases and denoising is insufficient
Solution Approach 1:
The patent implements preliminary discharging of the pull-up node during the non-output phase through the carry signal output terminal before the next output cycle begins. This preliminary action ensures complete discharge and denoising, preventing residual charges from affecting the next output phase, thereby reducing power consumption without significantly increasing circuit complexity.
Solution Approach 2:
The patent uses the pulled-down pull-up node signal as feedback to control the carry signal output terminal. This feedback mechanism ensures that the discharging operation is automatically triggered when needed, achieving complete denoising and power optimization while maintaining relatively simple circuit operation through intelligent control.
Data Source
AI summary
A shift register unit includes: a pull-up node control unit; a pull-down control node control unit connected with a first level output terminal, and configured to control an electrical potential at a pull-down control node to be a second level when an electrical potential at a pull-up node is a first level, and to control a pull-down control node to be connected with a first level output terminal when the electrical potential at the pull-up node is a third level; a pull-down node control unit; a gate driving signal output unit; and a carry signal output unit configured to control a carry signal output terminal to output a carry signal under the control of the pull-up node and the pull-down node. The carry signal output terminal provides an input signal to a shift register unit in an adjacent next stage.