Pixelated Capacitor Charge-Sharing Readout Without Dedicated ADCs
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Solution Overview
Problem
Existing pixelated capacitive sensors using CMOS technology are costly in terms of area, power, and complexity due to the need for dedicated Analog to Digital Converters (ADCs for each row/column of pixels.
Innovation Solution
The capacitive sensing cells are reused for quantization, forming a read-out circuit that includes a sensor array, comparator, and digital controller, eliminating the need for dedicated ADCs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dedicated ADCs are used for every row/column of pixels, then sensing precision is improved, but device complexity increases
Solution Approach 1:
The pixel array is designed to perform multiple functions: it serves as both the sensing element and the quantization element. The same capacitive pixels that detect the physical quantity are reused as DAC elements in the charge-sharing readout circuit, eliminating the need for separate ADC hardware and reducing device complexity while maintaining measurement precision.
Solution Approach 2:
The sensing function and quantization function are merged into a single integrated circuit block. The pixel array and readout circuit share common capacitive elements, combining what would traditionally be separate components into one unified structure that reduces overall system complexity.
2Measurement precision
If dedicated ADCs are used for every row/column of pixels, then sensing precision is improved, but area increases
Solution Approach 1:
The capacitive pixels serve dual purposes as both sensors and quantization elements. By reusing the same physical pixels for both sensing and DAC functions, the area required for dedicated ADC hardware is eliminated, significantly reducing the total chip area while preserving sensing precision.
Solution Approach 2:
The sensing array and quantization circuit are merged into a single structure where the pixel array itself provides the quantization function. This integration eliminates the need for separate ADC blocks, reducing the overall area occupied by the sensor system.
3Measurement precision
If dedicated ADCs are used for every row/column of pixels, then sensing precision is improved, but power consumption increases
Solution Approach 1:
The pixel array performs both sensing and quantization functions, eliminating the need for power-hungry dedicated ADC circuits. The charge-sharing readout mechanism uses the inherent capacitive properties of the pixels themselves, requiring minimal additional power while maintaining high measurement precision.
Solution Approach 2:
By merging the sensing and quantization functions into a single circuit, the power consumption associated with separate ADC operations is eliminated. The integrated charge-sharing readout requires significantly less power than traditional approaches using dedicated ADCs for each pixel row or column.
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 reduces hardware requirements, lowers production costs, and improves efficiency in terms of area and power usage while maintaining effective sensing capabilities.
Implementation Method 1
pixelated capacitor sensor charge sharing readout system
Data Source
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AI summary
Pixelated capacitive sensor systems and methods of operating pixelated capacitive sensor systems are provided. Pixelated capacitive sensor systems include a sensor array including a plurality of sense capacitors and a top plate, a comparator operatively connected to each sense capacitor and the top plate of the sensor array, a switch matrix operatively connected to each sense capacitor and the top plate of the sensor array, and a digital controller operatively connected to the comparator and the switch matrix. A read-out circuit may be formed by the sensor array, the comparator, the digital controller, and the switch matrix. Methods of operating pixelated capacitive sensor systems include providing a capacitive sensor system, sampling by the capacitive sensor system, toggling the sense capacitors by the digital controller, and running a conversion algorithm by the digital controller.