Gate Driving Circuit Node Potential Compensation for Touch Display Stability
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Solution Overview
Problem
The existing gate driving circuits in touch display panels experience potential reduction in pull-up nodes due to long time intervals between shift register units outputting gate turn-on signals, leading to instability in the gate turn-on signal and abnormal operation of TFTs.
Innovation Solution
A node potential compensation unit is introduced between pull-up nodes of adjacent shift register units, connected to a touch switch terminal, to compensate for the potential of the next stage's pull-up node during touch phases, ensuring a stable state and normal operation of TFTs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple touch periods are inserted between display periods to enable touch operation, then the touch display panel can perform both display and touch functions, but the long time interval causes potential reduction in the pull-up node of the next stage shift register unit, leading to unstable gate turn-on signals and abnormal TFT operation
Solution Approach 1:
The patent applies preliminary action by introducing a compensation signal in advance during the touch period to maintain the potential of the pull-up node before it can deteriorate. The compensation signal is generated based on the state of the current stage pull-up node and is applied to the next stage pull-up node proactively, preventing potential reduction before it occurs. This ensures the gate turn-on signal remains stable even during long intervals caused by multiple touch periods.
2Duration of action of moving object
If a long time interval is set between the output of gate turn-on signals by adjacent shift register units to accommodate touch periods, then touch operations can be performed, but leakage current through TFTs causes potential reduction in the pull-up node, resulting in reduced gate turn-on signal amplitude
Solution Approach 1:
The patent implements feedback by using the potential state of the current stage pull-up node as input to generate a compensation signal that is fed back to the next stage pull-up node. The compensation signal generation circuit monitors the potential of the current pull-up node and dynamically adjusts the compensation amount applied to the next stage, creating a closed-loop control system that maintains signal amplitude stability despite long touch period intervals.
3Use of energy by stationary object
If the pull-up node potential is allowed to reduce during touch periods, then the circuit can operate in standby during touch operations, but this leads to insufficient gate turn-on signal when the next stage shift register unit operates, causing TFT turn-on failure
Solution Approach 1:
The patent introduces an intermediary compensation signal generation circuit that mediates between the current stage pull-up node and the next stage pull-up node. This intermediary circuit generates a compensation signal based on the current stage state and applies it to the next stage, acting as a buffer that prevents the direct transmission of potential reduction effects. This ensures the next stage can reliably turn on TFTs even when the system is in standby during touch operations.
Data Source
AI summary
The present disclosure provides a gate driving circuit in which a node potential compensation unit connected to a touch switch terminal is provided between pull-up nodes of two stages of shift register units of each preset unit group. The node potential compensation unit may compensate for, under the control of both of a pull-up node of a previous stage of shift register unit and the touch switch terminal, a potential of a pull-up node of a next stage of shift register unit, and may enable the potential of the pull-up node of the next stage of shift register unit to be in a stable state, so as to improve the stability of the potential of the gate turn-on signal output by the next stage of shift register unit, thereby enabling a TFT of a pixel region in a corresponding line to be normally turned on and improving a display performance.