Adaptive Touch Screen Controller Noise Filtering
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Solution Overview
Problem
Touch screen controllers face challenges in balancing noise cancellation and power consumption due to the size and performance of filters, leading to increased response time and current consumption when high-performance filters are used, and inefficiency when low-performance filters are employed.
Innovation Solution
A touch screen controller that adjusts the number of sensing cycles based on noise detection, using a comparator, filter, and ADC to determine the presence of noise and adjust the number of sensing cycles, thereby optimizing power consumption and dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a high-performance filter with increased external noise cancellation effect is used, then noise cancellation performance is improved, but the physical size of the sensing circuit increases and power consumption increases
Solution Approach 1:
The filter dynamically adjusts the number of sensing cycles based on detected noise levels. When noise is detected, the filter increases the number of sensing cycles to enhance noise cancellation. When no noise is detected, it reduces the number of sensing cycles to minimize power consumption. This dynamic adaptation resolves the contradiction between maintaining high noise cancellation performance and reducing power consumption.
Solution Approach 2:
The system changes the operational parameter (number of sensing cycles) of the filter based on environmental conditions (noise presence). By adjusting this parameter dynamically, the system achieves high noise cancellation performance only when necessary, thereby reducing overall power consumption while maintaining effectiveness when noise is present.
2Object-affected harmful factors
If a high-performance filter with increased external noise cancellation effect is used, then noise cancellation performance is improved, but the response speed is reduced
Solution Approach 1:
The filter adjusts the number of sensing cycles dynamically based on noise detection. When noise is detected, it increases sensing cycles for thorough noise cancellation. When no noise is detected, it reduces sensing cycles to minimize response time. This dynamic adjustment resolves the contradiction between noise cancellation performance and response speed.
Solution Approach 2:
The system changes the operational parameter (number of sensing cycles) based on environmental conditions. By reducing the number of sensing cycles when noise is absent, the system achieves faster response speed while maintaining noise cancellation capability when needed, thus resolving the speed-performance trade-off.
3Object-affected harmful factors
If the number of sensing cycles is increased to cancel external noise, then noise cancellation is improved, but power consumption increases
Solution Approach 1:
The system employs a feedback mechanism where the controller detects the presence of external noise and adjusts the number of sensing cycles accordingly. When noise is detected, the controller increases the number of sensing cycles to improve noise cancellation. When no noise is detected, it reduces the number of sensing cycles to minimize current consumption. This feedback-based adaptive control resolves the contradiction between noise cancellation effectiveness and power consumption.
Solution Approach 2:
The system dynamically changes the operational parameter (number of sensing cycles) based on detected noise levels. By adjusting this parameter in response to environmental conditions, the system achieves effective noise cancellation only when necessary, thereby minimizing overall current consumption while maintaining performance when noise is present.
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
The solution reduces power consumption and increases the operation dynamic range by dynamically adjusting the number of sensing cycles in response to noise levels, improving the overall performance of the touch screen controller.
Implementation Method 1
a filter for generating a second output signal by integrating the first output signal in each sensing cycle
Data Source
AI summary
A touch screen controller controlling a capacitive touch screen includes a first comparator that compares a reference signal with a sensing signal, and generates a first output signal. The capacitive touch screen includes capacitive touch sensors connected to a sensing line and a drive line, and that sense a touch event. The sensing signal is output from the sensing line. The touch screen controller further includes a filter that generates a second output signal by integrating the first output signal in each sensing cycle of the filter, an analog-to-digital converter that converts the second output signal to a digital signal, and a controller that determines at least one of whether a noise is generated and whether the touch event is generated based on a reference digital signal and the digital signal, and that adjusts the number of the sensing cycles of the filter based on a result of the determination.