Multi-Frequency Impedance Measurement Without AFE Chips
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Solution Overview
Problem
Current electrochemical impedance measurement techniques are costly, power-consuming, and bulky due to the use of specialized analog front-end (AFE) chips, which hinder device miniaturization and battery life in low-power applications.
Innovation Solution
Concurrent multi-frequency impedance measurement systems utilizing standard microprocessors with pulse width modulator and analog-to-digital converter functions, eliminating the need for AFE chips, enable efficient impedance spectrum acquisition in a single scan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If specialized analog front-end (AFE) chips are used for impedance measurement, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses a microcontroller unit (MCU) to perform impedance measurements that were traditionally done by specialized AFE chips. The MCU copies the measurement functionality by generating excitation signals through its PWM module and processing the resulting signals through its ADC, thereby eliminating the need for separate AFE chip hardware while maintaining measurement capability.
Solution Approach 2:
The patent makes the microcontroller unit perform multiple functions: it generates excitation signals via PWM, converts analog signals to digital via ADC, and processes the impedance measurement data. This multi-functional approach replaces the specialized AFE chip, reducing device complexity while maintaining measurement precision through software-based signal processing algorithms.
2Measurement precision
If specialized analog front-end (AFE) chips are used for impedance measurement, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive specialized AFE chip hardware with a standard microcontroller unit that can perform the same impedance measurement functions. By copying the measurement functionality into software and using existing MCU peripherals (PWM and ADC), the patent eliminates the need for costly specialized components, thereby reducing manufacturing costs while maintaining measurement precision.
Solution Approach 2:
The patent uses a standard, inexpensive microcontroller unit instead of a specialized, expensive AFE chip. The MCU is a common, cost-effective component that can be easily sourced and integrated, making the overall device more affordable and easier to manufacture at scale while still achieving the required measurement precision through software processing.
3Measurement precision
If specialized analog front-end (AFE) chips are used for impedance measurement, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent consolidates multiple functions (signal generation, signal conversion, and measurement processing) into a single microcontroller unit. The MCU's integrated PWM and ADC peripherals handle the excitation signal generation and output signal conversion, eliminating the need for a separate power-hungry AFE chip. This integration reduces overall power consumption while maintaining measurement precision through efficient use of the MCU's existing resources.
Solution Approach 2:
The patent copies the AFE chip's measurement functionality into the MCU's software and uses the MCU's built-in peripherals to perform the same functions. By using the MCU's existing PWM and ADC capabilities instead of dedicated AFE hardware, the patent achieves the same measurement precision with significantly lower power consumption, as the MCU can operate in low-power modes and shares resources efficiently.
4Measurement precision
If specialized analog front-end (AFE) chips are used for impedance measurement, then measurement precision is improved, but device size increases
Solution Approach 1:
The patent integrates the functions of the specialized AFE chip into the microcontroller unit, which already contains the necessary PWM and ADC peripherals. This integration eliminates the need for separate AFE chip components and reduces the overall device footprint, as the MCU handles signal generation, conversion, and processing in a single integrated package, thereby maintaining measurement precision while reducing device size.
Solution Approach 2:
The patent merges the AFE chip's functionality with the microcontroller unit by using the MCU's existing peripherals (PWM for signal generation and ADC for signal conversion) to perform the impedance measurement tasks. This merging of functions into a single component reduces the number of separate components needed, thereby reducing device size and complexity while maintaining the required measurement precision.
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 device costs, power consumption, and size while maintaining accuracy, enabling frequent impedance measurements and improving patient outcomes in medical devices.
Implementation Method 1
Electrochemical impedance measurements of a substance can provide useful information about the substance
Implementation Method 2
decomposing the input signal includes applying a first Fourier transform to the input signal, and decomposing the output signal includes applying a second Fourier transform to the output signal
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
Systems and methods for concurrent multi-frequency impedance measurements to characterize a substance of interest (e.g., analyte concentration) are disclosed herein. Generally, in some variations a method for characterizing a substance includes generating an input signal having a first set of frequency components across a plurality of frequencies, exciting an electrode arrangement with the input signal wherein the electrode arrangement is in contact with the substance. receiving an output signal from the excited electrode arrangement, the output signal having a second set of frequency components across the plurality of frequencies, determining an impedance signature of the substance across the plurality of frequencies, based on the first and second sets of frequency components, and characterizing the substance based on the impedance signature.