Bioimpedance Measurement Using Switching Electrode Configurations

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Solution Overview

Problem

Existing bioimpedance analysis (BIA) devices for wearable electronics face challenges such as sensitivity to high contact impedance, requirement for external parasitic and circuit element consideration, and inability to reduce electrode size, leading to inaccurate measurements and complex device designs.

Innovation Solution

A device and method for BIA that utilize a configuration with first and third contact electrodes on one part of the body and second and fourth contact electrodes on another part, along with an alternating current source, current measurement circuit, voltage measurement circuits, and a switch to form different current measurement paths, allowing for accurate bioimpedance determination without considering contact impedances or external components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If compact electrodes are used to reduce device size, then device form factor is improved, but contact impedance increases and measurement accuracy degrades

Engineering Contradiction:

Improvedevice sizeVSAvoidbioimpedance measurement accuracy

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent divides the measurement process into multiple sequential steps, performing multiple measurements with different electrode configurations and processing them through a system of equations to eliminate the effects of contact impedance and parasitic elements, thereby maintaining accuracy with compact electrodes

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces computational processing as an intermediary between the raw measurement signals and the final bioimpedance result, using mathematical models to compensate for the degraded signal quality caused by high contact impedance from compact electrodes

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If multiple functions are integrated into wearable devices, then device versatility is improved, but parasitic effects increase and measurement accuracy degrades

Engineering Contradiction:

Improvedevice functionalityVSAvoidbioimpedance measurement accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent extracts and separately measures the parasitic effects caused by adjacent circuits and components, then mathematically removes their influence from the bioimpedance measurement, allowing multiple functions to coexist without degrading measurement accuracy

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses the measured data from multiple configurations to feedback and calculate correction factors that compensate for parasitic effects, continuously improving measurement accuracy despite the presence of other circuit functions

Inventive Principle:

Principle #23Feedback

3Area of stationary object

If electrode contact area is reduced for compact design, then device compactness is improved, but contact impedance increases and measurement reliability degrades

Engineering Contradiction:

Improveelectrode contact areaVSAvoidmeasurement reliability

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The patent changes the measurement parameters by using multiple different electrode configurations and measurement frequencies, processing the varying results through mathematical models that are insensitive to contact impedance variations, thereby maintaining reliability with reduced contact area

Inventive Principle:

Principle #35Parameter changes

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 achieves improved accuracy in bioimpedance determination, comparable to professional devices, while simplifying the device construction and method, reducing memory requirements, and minimizing energy consumption, thus enabling accurate measurements across various skin conditions and device designs.

Implementation Method 1

an alternating current source, current measurement circuit, wherein the alternating current source and the current measurement circuit have a common ground

Methodology Applied

Scientific EffectAlternating current:

Implementation Method 2

at least one voltage measurement circuit configured to measure a voltage between one of the first and third contact electrodes and the common ground, and between one of the second and fourth contact electrodes and the common ground

Methodology Applied

Scientific EffectElectrical impedance measurement:

Data Source

PatentUS12295710B2Device and method for human body impedance analysis insensitive to high contact impedance and parasitic effects

Publication Date: 2025.05.13 SAMSUNG ELECTRONICS CO LTD

AI summary

A device for bioimpedance determining is provided. The device includes contact electrodes for contacting with one part of the user's body and for contacting with another part of the user's body, an alternating current source, a current measurement circuit, a voltage measurement circuit in the region of one of the contact electrodes for contacting with one part of the user's body, and in the region of one of the contact electrodes for contacting with another part of the user's body, a switch connected to the alternating current (AC) source and to the current measurement circuit and configured to form a first and a second current measurement paths so that the current flows through the user's body from one part of the body to another part of the body, and a control unit configured to determine the user's bioimpedance based on the measured current and voltage values.