Capacitive Sensor Integrated Circuit Analyte Detection
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Solution Overview
Problem
Capacitive sensors for analyte detection, such as moisture, have a slow response time due to limited diffusion rates and the need for analog-to-digital conversion, which increases processing time and costs.
Innovation Solution
Incorporating a plurality of sensing capacitors in the signal digitization stage, where the number of capacitive elements adjusts based on analyte levels, eliminating the need for a separate analog-to-digital converter and reducing sensor size and manufacturing costs, with capacitive elements having varying capacities to accurately determine analyte levels without additional conversion steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a separate analog-to-digital converter is used for the sensor signal, then measurement precision is improved, but response time worsens and device complexity increases
Solution Approach 1:
The patent merges the capacitive sensing elements with the analog-to-digital conversion circuitry into a single integrated unit. The capacitive elements are directly connected to the input of the A/D converter, eliminating the need for separate signal routing and processing stages. This integration allows the sensing and digitization processes to occur simultaneously, reducing the overall response time while maintaining measurement precision through direct signal conversion.
2Measurement precision
If a separate analog-to-digital converter is used for the sensor signal, then measurement precision is improved, but device complexity worsens
Solution Approach 1:
The patent combines multiple functional blocks including the capacitive sensing elements, signal conditioning circuitry, and analog-to-digital converter into a single integrated device. The capacitive elements are directly interfaced with the A/D converter input, eliminating intermediate signal routing stages and reducing the number of discrete components. This merging approach simplifies the overall device architecture while preserving measurement precision through direct signal conversion.
Solution Approach 2:
The integrated device performs multiple functions within a single unit: it senses the target quantity through capacitive elements, conditions the signal, converts it to digital form, and outputs the measurement. The capacitive sensing elements serve both as the detection mechanism and as part of the signal processing circuitry, allowing the device to handle sensing and digitization tasks simultaneously without requiring separate dedicated components for each function.
3Measurement precision
If the number of capacitive elements is increased to improve measurement precision, then measurement precision is improved, but device complexity worsens
Solution Approach 1:
The patent segments the capacitive sensing function into multiple discrete capacitive elements that can be independently controlled and processed. Each capacitive element corresponds to a specific measurement interval or precision level, allowing the system to divide the measurement task into manageable units. This segmentation enables the use of multiple capacitive elements for improved precision while maintaining manageable device complexity through systematic organization and control of each element.
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 significantly enhances response speed and reduces sensor size and manufacturing costs by directly translating the number of capacitive elements to analyte levels, providing faster and more cost-effective digitized sensor readings.
Implementation Method 1
The analyte of interest is typically absorbed by the dielectric medium, which causes the dielectric constant of the dielectric medium to change
Data Source
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AI summary
Disclosed is a sensor (100, 200) for sensing an analyte of interest, the sensor comprising a plurality of capacitive elements (120), each capacitive element comprising a pair of electrodes (122, 126) separated by a dielectric medium (124) wherein the dielectric constant of the dielectric medium of at least one of the capacitive elements is sensitive to the analyte of interest, the sensor further comprising a comparator (130, 230) adapted to compare a selected set of said capacitive elements against a reference signal and to generate a comparison result signal, and a controller (150, 250) for iteratively selecting said set in response to said comparison result signal, wherein the sensor is arranged to produce a digitized output signal indicative of the sensed level of the analyte of interest. An IC comprising such a sensor, an electronic device comprising such an IC and a method of determining a level of an analyte of interest using such a sensor are also disclosed.