Shift Register Unit With Control Circuit For Voltage Maintenance
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Solution Overview
Problem
In touch control display panels, maintaining a high voltage at the pull-up node during touch control signal intervals is challenging due to increased leakage current at high temperatures, leading to abnormal output signals.
Innovation Solution
A shift register unit comprising a shift register circuit and a control circuit that outputs a hold signal to maintain a high voltage at the pull-up node using AC signals from control terminals, alternately controlling voltages at pull-down nodes to prevent voltage drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional shift register circuit is used without additional control circuits, then the device complexity is low, but the voltage at the pull-up node cannot be maintained during touch control intervals due to leakage current
Solution Approach 1:
The control circuit proactively applies a hold signal to the pull-up node before voltage degradation occurs during touch control intervals. This preliminary action counteracts the upcoming leakage current effect, maintaining voltage stability without requiring complex additional power supply circuits.
Solution Approach 2:
A control circuit is introduced as an intermediary component between the existing shift register circuit and the pull-up node. This intermediary applies compensating signals to maintain voltage during touch control intervals, resolving the contradiction by adding minimal complexity while achieving reliable voltage maintenance.
2Adaptability or versatility
If the shift register operates continuously without idle intervals, then productivity is high, but no time is available to provide touch control signals
Solution Approach 1:
The system utilizes periodic intervals between gate scanning signal outputs to insert touch control signal transmission. This periodic utilization of idle time allows both shift register operation and touch control functionality to coexist without compromising signal output efficiency or adding complexity.
3Reliability
If additional power supply circuits are added to maintain voltage, then voltage stability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The control circuit utilizes existing signal resources within the shift register system to generate hold signals that maintain voltage at the pull-up node. This self-service approach achieves voltage stability without requiring external power supply circuits, thereby avoiding increased manufacturing complexity and cost.
Data Source
AI summary
A shift register unit includes a shift register circuit and a control circuit. The control circuit is electrically coupled to the shift register circuit and at least one control terminal, and is configured, based on at least one control signal respectively from the at least one control terminal, to output a hold signal to a pull-up node in the shift register circuit such that a high voltage maintains at the pull-up node during a specified time period. The shift register includes a plurality of shift register circuits cascadedly connected in stages, includes a first shift register circuit, which is coupled with a control circuit to form a shift register unit described above. The above shift register can be used in an array substrate in a display apparatus with touch control functionality.