Mode-Configurable Touch Preamp for Noise Filtering and Low Power
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Solution Overview
Problem
Conventional touch screen devices face limitations such as high current drain, poor response time, especially under fast motion, and performance degradation in extreme conditions with electromagnetic interference and contaminants.
Innovation Solution
The implementation of a capacitive touch screen system with a controller circuit that includes a digital touch subsystem, a touch front end, and a touch back end, utilizing mutual capacitance sensing, asymmetric scan maps, and a mode-configurable amplifier to enhance signal-to-noise ratio and reduce power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional touch screen devices use standard capacitive sensing circuits, then basic touch detection is achieved, but current drain becomes too great affecting power dissipation
Solution Approach 1:
The patent implements dynamic scanning rate adjustment where the controller circuit varies the scanning rate of capacitive sensing based on detected touch activity. During idle periods, scanning occurs at lower rates to reduce power consumption, while during active touch interaction, scanning rate increases to maintain responsive performance. This dynamic adaptation resolves the contradiction between maintaining adequate sensing performance and minimizing continuous power drain.
Solution Approach 2:
The patent employs configurable amplifier gain settings and adjustable filtering parameters that can be modified based on environmental conditions and touch states. By changing these electrical parameters dynamically, the system optimizes signal-to-noise ratio while minimizing the energy required for sensing operations, thereby reducing overall current drain while maintaining detection accuracy.
2Speed
If conventional touch screens use simple scanning circuits, then device complexity is reduced, but response time becomes poor especially under fast motion
Solution Approach 1:
The patent divides the capacitive sensing array into multiple independently controllable zones or groups that can be scanned asynchronously. Instead of scanning the entire touch surface sequentially at a single rate, different regions can be scanned at different rates based on detected activity levels. This segmentation enables faster response in active regions while maintaining lower overall complexity compared to a fully high-speed scanning system.
Solution Approach 2:
The patent implements predictive scanning where the controller anticipates potential touch events by analyzing motion patterns and pre-positions scanning resources in high-probability regions. This preliminary action allows the system to maintain fast response times in anticipated interaction zones without requiring the entire system to operate at maximum scanning speed continuously, thereby managing complexity while improving speed.
3Reliability
If conventional touch screens lack filtering circuits, then device complexity is minimized, but performance degrades in extreme conditions with electromagnetic interference and contaminants
Solution Approach 1:
The patent introduces configurable filtering circuits that act as intermediaries between the capacitive sensing elements and the control logic. These filters selectively attenuate noise signals from electromagnetic interference and environmental contaminants while passing valid touch signals. The filters are configured with adjustable parameters that can be adapted to different environmental conditions, providing reliable performance in extreme conditions without requiring overly complex shielding or isolation circuits.
4Adaptability or versatility
If touch screens use fixed scanning patterns, then ease of operation is maintained, but adaptability to different environments and usage scenarios is limited
Solution Approach 1:
The patent implements dynamically reconfigurable scanning patterns that automatically adapt to detected touch behaviors and environmental conditions. The controller circuit monitors touch frequency, duration, and spatial distribution to adjust scanning priorities and rates in real-time. This dynamic adaptation provides environmental versatility without requiring manual configuration or complex user intervention, maintaining ease of operation while enhancing adaptability.
Solution Approach 2:
The patent designs a unified control architecture that can operate in multiple modes (e.g., high-speed scanning for fast motion detection, low-speed for power saving, selective scanning for specific zones) using the same hardware resources. This multi-functional design allows the system to adapt to different environments and usage scenarios without requiring separate specialized circuits for each function, thereby maintaining operational simplicity while achieving versatility.
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 improves the responsiveness and durability of touch screen devices, reducing power consumption and enhancing performance in diverse environments by effectively detecting touch events and filtering noise, thereby addressing the limitations of conventional systems.
Implementation Method 1
A capacitive touch panel includes a plurality of capacitive sensing elements arranged in a scanable array and disposed behind a display device
Implementation Method 2
Transmit circuitry is coupled to the capacitive touch panel and is configured to stimulate the capacitive touch panel in accordance with a stimulate algorithm
Data Source
AI summary
A mode-configurable amplifier comprises a single-ended input for receiving a received signal from a capacitive touch panel, a differential output operable to carry a differential processed signal to a subsequent processing stage, and processing circuitry in communication with the single ended input and the differential output. The processing circuitry comprises mode selection inputs and mode selection circuitry in communication with the mode selection inputs. The mode selection circuitry is operable to configure the processing circuitry into a current operating mode selected from a high-pass filter mode, bandpass filter mode, and a trans-capacitive gain mode. The high-pass filter mode is operable to high-pass filter the received signal to obtain the differential processed signal. The bandpass filter mode is operable to bandpass filter the received signal to obtain the differential processed signal. The wideband gain mode is operable to amplify the received signal to obtain the differential processed signal.