Shift Register Pull-Down Module Prevents Instantaneous High Current
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing shift register technologies face issues with insufficient turning off during the charging phase, leading to increased power consumption and potential device damage due to instantaneous high currents caused by simultaneous high and low level signal outputs to the pull-down node.
Innovation Solution
A shift register unit with a pull-down module controlled by the pull-down node, capable of outputting either a high or low level signal based on the current operating phase, preventing simultaneous signal outputs and ensuring proper state maintenance of the pull-up and output nodes, thereby reducing power consumption and protecting the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the CKB node outputs a high level signal during the charging phase, then the pull-down node PD receives the high level signal, but this causes insufficient turning off by pulling down and generates instantaneous high current
Solution Approach 1:
The patent applies preliminary anti-action by introducing a pull-down module that actively pulls down the pull-up node PU and output node Out(n) during the reset phase and maintaining phase. This pre-active pulling down counteracts the potential harmful high current that would occur if the CKB node output high level during charging phase, preventing the problem before it occurs.
Solution Approach 2:
The pull-down module acts as an intermediary between the CKB node and the pull-up node PU/output node Out(n). It mediates the signal transmission by conditionally blocking or allowing the high level signal from CKB to reach PU and Out(n), thereby preventing instantaneous high current while maintaining proper signal output capability.
2Reliability
If the pull-up transistor charges the first capacitor module during charging phase, then the output transistor T1 is maintained turned on, but this requires the pull-up node and output node to be maintained in low level state during reset and maintaining phases
Solution Approach 1:
The patent merges the control functions for pull-up node PU and output node Out(n) into a single pull-down module. This module simultaneously controls both nodes to be in low level state during reset and maintaining phases, simplifying the overall control mechanism while ensuring reliable output transistor operation.
Solution Approach 2:
The pull-down module serves multiple functions: it pulls down both the pull-up node PU and output node Out(n), maintains low level states during reset and maintaining phases, and prevents instantaneous high current. This multi-functionality reduces device complexity while maintaining reliability.
3Ease of operation
If simultaneous high and low level signals are output to the pull-down node, then the turning off capability is insufficient, but this increases power consumption and may cause device damage
Solution Approach 1:
The pull-down module applies preliminary anti-action by actively pulling down the output nodes during reset and maintaining phases, ensuring proper signal levels before the charging phase begins. This prevents the need for simultaneous high and low level outputs that would cause excessive power consumption and potential device damage.
Data Source
AI summary
A shift register unit, a shift register, a gate driving circuit and a display device are discloses. The shift register unit has an output node Out(n) of a current stage, a pull-up node PU and a pull-down node PD, and the shift register unit includes a first capacitor module C1, a pull-down module and a pull-down control module, and the pull-down control module is configured to output one of a high level signal and a low level signal to the pull-down node (PD) in accordance with a current operating phase.