Level Converter Circuit for Uniform GOA Row Charging
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Solution Overview
Problem
In in-cell touch display devices, long horizontal blanking time leads to reduced charging time for subsequent rows, resulting in parts of the picture appearing relatively dark due to voltage decrease at the pull-up node during the blanking period.
Innovation Solution
A level converter and gate driving circuit with a level converting unit that determines whether to directly output or convert input signals based on control signals, using resistors and switches in parallel to manage rise times, ensuring consistent output signal rise times across rows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If long horizontal blanking time is used for touch detection, then touch function is enabled, but display brightness decreases due to reduced charging time
Solution Approach 1:
The patent applies different signal processing strategies to different row groups. Specifically, rows affected by long horizontal blanking time (e.g., rows 7-9 in a 10-row display) receive compensated drive signals with adjusted rise times, while other rows use normal signaling. This localized compensation ensures touch functionality is maintained without compromising overall display brightness.
Solution Approach 2:
The patent changes the rise time parameter of drive signals dynamically based on the row being driven. During long horizontal blanking periods, signals for affected rows are transformed to have extended rise times, allowing sufficient charging time for pixel electrodes. This parameter adjustment compensates for the reduced charging window while maintaining proper display brightness.
2Speed
If signal rise time is shortened for faster scanning, then scanning speed increases, but display uniformity deteriorates due to inconsistent charging across rows
Solution Approach 1:
The patent dynamically adjusts signal characteristics based on real-time operating conditions. The level converter circuit transforms input signals with normal rise times into output signals with adjusted rise times depending on which row group is being driven. This dynamic adaptation ensures each row receives appropriately timed signals, maintaining display uniformity across all rows while preserving overall scanning speed.
Solution Approach 2:
The patent divides the display rows into different groups based on their charging requirements. Rows are segmented such that those affected by long horizontal blanking receive special compensation, while others follow the normal scanning rhythm. This segmentation allows differential signal processing that maintains both scanning speed and display uniformity across heterogeneous row requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution prolongs the charging time of GOA units during horizontal blanking, improving the display quality by maintaining consistent output signal rise times and preventing dark display issues in in-cell touch panels.
Implementation Method 1
the level converting unit comprises first to N-th resistors and first to N-th switches, wherein a n-th resistor and a n-th switch are connected in parallel
Data Source
AI summary
A level converter and an operation method thereof, a gate driving circuit and a display device. The level converter includes: N input terminals, configured to receive N input signals; N control signal terminals, configured to receive N control signals; N output terminals, configured to output N output signals; and a level converting unit, connected to the N input terminals, the N control signal terminal and the N output terminals and configured to, according to a n-th control signal of the control signal terminals, determine to directly output a n-th input signal as a n-th output signal, or convert the n-th input signal and then output the converted n-th input signal as the n-th output signal; wherein when the n-th input signal is converted, the n-th input signal has shorter rise time and the n-th output signal has longer rise time, and N is a positive integer, 1.ltoreq.n.ltoreq.N.