Multi-Controller Capacitive Sensing With Synchronized Shield Timing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Large capacitive sensing devices face challenges in control due to the finite number of connections a device controller has to signal lines, leading to difficulties in maintaining sensitivity and reducing noise from cross-coupling effects.
Innovation Solution
Implementing multiple device controllers connected to different portions of capacitive sensors, with switching devices controlling charging and discharging of drive and sense lines, and a common node or shield, synchronized to prevent overlapping events and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single device controller is used to control a large capacitive sensing device, then the device complexity is reduced, but the measurement precision and sensitivity deteriorate due to the finite number of connections available to signal lines
Solution Approach 1:
The capacitive sensing device is divided into multiple zones, with each zone controlled by a separate device controller. This segmentation allows each controller to manage a specific portion of the sensing device, thereby maintaining high measurement precision and sensitivity in each zone while controlling the overall system complexity through modular architecture.
2Measurement precision
If multiple device controllers are implemented to maintain sensitivity in large capacitive sensing devices, then the measurement precision is improved, but the device complexity increases due to multiple controllers and their interconnections
Solution Approach 1:
The sensing device is segmented into distinct zones, each handled by a dedicated controller, which maintains precision while managing complexity through division.
Solution Approach 2:
Multiple device controllers are designed with identical or similar functional capabilities, allowing them to operate independently yet interchangeably across different zones. This universality simplifies the overall system architecture by using standardized components rather than requiring unique complex control logic for each zone.
3Area of stationary object
If drive and sense lines are densely connected to cover a large sensing area, then the area of the sensing device is increased, but the object-generated harmful factors increase due to cross-coupling noise between lines
Solution Approach 1:
By dividing the large sensing device into multiple smaller zones controlled by separate controllers, the density of drive and sense lines in each zone is reduced. This segmentation decreases the proximity of lines within each zone, thereby reducing capacitive coupling and cross-talk noise while still achieving a large overall sensing area through the combination of multiple zones.
4Quantity of substance
If the number of signal lines is increased to control more capacitive sensors, then the quantity of sensors is increased, but the ease of operation deteriorates due to the finite number of connections a device controller can handle
Solution Approach 1:
The system is segmented into multiple controller units, each managing a subset of capacitive sensors. This allows the total number of sensors to be scaled up by simply adding more controller units rather than increasing the connection capacity of a single controller, thereby maintaining ease of operation through modular, manageable units.
Solution Approach 2:
Multiple device controllers are merged into a coordinated system where each controller manages a portion of the capacitive sensors. The controllers work together in parallel to control the entire array of sensors, effectively combining their individual connection capabilities to handle a large total number of sensors without overloading any single controller.
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 approach allows for scalable capacitive sensing systems, maintaining sensitivity and reducing noise, enabling effective force detection and touch interaction across larger surfaces.
Implementation Method 1
a capacitive sensing device capable of detecting changes in capacitance in response to an applied force
Data Source
AI summary
A capacitive sensing device can include multiple capacitive sensors. A first device controller is operatively connected to a portion of the capacitive sensors, while a second device controller is operatively connected to another portion of capacitive sensors. A common node or shield can be connected between the first device controller and the second device controller. Charging and discharging events of selected drive lines in the capacitive sensing device and/or of the common node or shield can be synchronized to reduce undesirable effects such as noise and/or to prevent the charging events and the discharging events from overlapping with each other. One or more reference capacitive sensors can be shared by the multiple device controllers.