Floating Front-End Amplifier for One-Wire Biopotential Sensing
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Solution Overview
Problem
Current biopotential and impedance measurement systems face challenges in minimizing noise and motion artifacts, particularly in ambulatory settings, due to high impedance and the need for multiple electrodes and cables, which can be uncomfortable and obtrusive, and struggle with accurate assessment of cough signals amidst variability and ambient noise.
Innovation Solution
A floating front-end amplifier with embedded electronics and a one-wire connection system that uses floating power supplies and a feedback filter to minimize input impedance and noise, allowing for high-gain biopotential and impedance measurements with reduced cabling and discomfort, and enables non-supervised cough assessment through chest impedance measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple electrodes and cables are used for biopotential and impedance measurements, then measurement accuracy is improved, but patient comfort deteriorates and motion artifacts increase
Solution Approach 1:
The patent combines multiple measurement functions (biopotential measurement and impedance measurement) into a single integrated system that uses a common reference electrode and shared cabling. The measuring device integrates both ECG and impedance plethysmography capabilities, allowing simultaneous or alternating measurements through a unified electrode-cable-measuring device chain, thereby reducing the number of separate systems and improving patient comfort while maintaining measurement accuracy
2Measurement precision
If multiple electrodes and cables are used for biopotential and impedance measurements, then measurement accuracy is improved, but motion artifacts increase
Solution Approach 1:
The patent combines multiple measurement functions (biopotential measurement and impedance measurement) into a single integrated system that uses a common reference electrode and shared cabling. The measuring device integrates both ECG and impedance plethysmography capabilities, allowing simultaneous or alternating measurements through a unified electrode-cable-measuring device chain, thereby reducing the number of separate systems and improving patient comfort while maintaining measurement accuracy
3Measurement precision
If high impedance is used in measuring devices, then sensitivity to biopotentials is improved, but noise and motion artifacts increase
Solution Approach 1:
The patent employs feedback mechanisms in the measuring device to actively compensate for noise and interference. The system uses the common reference electrode to establish a stable reference potential and implements feedback control to minimize the effects of noise and motion artifacts on the high-impedance biopotential measurements, thereby maintaining sensitivity while reducing harmful factors
Data Source
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AI summary
The present invention relates to a floating front-end amplifier and to one-wire measuring devices. According to a main characteristic, the present invention relates to a follower amplifier with power supply biased by a controlled voltage source in such a way that the power supply potentials are, for the frequencies of interest, as close as possible to the potential of the follower output. The main purpose of the invention is to propose a front-end electronic circuit for biopotential and impedance measurements with outstanding performances (very high input impedance and gain very close to unity). In a preferred embodiment, the explicit guard electrode and the explicit electronic unit at the belt are no longer necessary; all electronics is embedded in units placed directly at the measurement sites. Moreover, the proposed front-end electronic circuit allows a drastic simplification of the cabling and connectors since all units are connected to only one wire (the theoretical minimum) for potential reference and current return. In a preferred embodiment, this wire does not even require an electrical isolation and can be easily embedded in the textile of a shirt, in a garment, mesh, belt, etc.