Touch Display Driving Circuit Power Reduction via Periodic Scan Segmentation
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Solution Overview
Problem
Capacitive touch panels consume power due to continuous scanning of electrostatic fields, which is inefficient when the panel is not being interacted with, leading to unnecessary energy usage.
Innovation Solution
A driving circuit with a detection module, interruption module, and selective scan module that periodically scans scan lines to detect touch input, turning off unnecessary scans and reducing power consumption by synchronously scanning only selected lines when the panel is idle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous scanning of all scan lines is performed to detect touch input, then touch detection responsiveness is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic scanning of scan lines instead of continuous scanning. The controller alternates between scanning periods and non-scanning periods, where during non-scanning periods power consumption is reduced. This periodic action maintains touch detection capability while significantly reducing overall power usage compared to continuous scanning of all lines.
Solution Approach 2:
The patent divides the scan lines into multiple groups and scans them at different time periods. Instead of scanning all scan lines continuously, the controller segments the scanning task across different time intervals, scanning only a subset of lines during each period. This segmentation allows the system to maintain comprehensive touch detection coverage while reducing the number of lines scanned simultaneously, thereby lowering power consumption.
2Measurement precision
If all scan lines are scanned periodically to ensure complete touch detection coverage, then measurement precision is improved, but the number of scanning operations increases leading to higher energy usage
Solution Approach 1:
The controller implements periodic scanning where scan lines are scanned in alternating periods rather than continuously. During first periods, certain scan lines are scanned; during second periods, other scan lines are scanned. This periodic approach ensures that over time all scan lines are covered for complete touch detection accuracy, while at any given moment fewer lines are being scanned, reducing instantaneous and average power consumption.
Solution Approach 2:
The patent segments the set of scan lines into multiple subsets that are scanned at different times. By dividing the complete set of scan lines into groups and assigning different groups to different scanning periods, the system maintains comprehensive coverage for accurate touch detection while reducing the scanning load in each individual period, thereby decreasing overall energy consumption.
Data Source
AI summary
A driving circuit and method for a touch panel having a plurality of scan lines includes a detection module, an interruption module and a selective scan module. The detection module can periodically scan the scan lines, so as to detect whether the touch panel is controlled by touch. The interruption module can turn off the detection module when the touch panel is not controlled by touch. The selective scan module can select at least one set of scan lines from the plurality of scan lines to periodically and synchronously scan the set of selected scan lines when the detection module is turned off, where scanning of the selected scan lines detects whether the touch panel is touched.