Biopotential Front-End Circuit for Adaptive Noise Compensation

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Solution Overview

Problem

Conventional biopotential signal acquisition systems are susceptible to noise such as motion artifacts and power-line induced noise, leading to erroneous results and high power consumption, necessitating low-power techniques to suppress these noise sources.

Innovation Solution

An apparatus with an analog frontend circuit and mixed-signal circuit that includes an instrumentation amplifier, ADC, and digital circuit for adaptive baseline tracking and power line interference compensation, using a digital-to-analog converter to generate an analog compensation signal to counteract input artifacts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional means are used to detect biopotential signals, then signal acquisition is achieved, but noise susceptibility increases leading to erroneous results

Engineering Contradiction:

Improvebiopotential signal detection accuracyVSAvoidnoise susceptibility

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by implementing an adaptive baseline tracking circuit that proactively compensates for baseline wandering and motion artifacts before they significantly degrade the signal quality. The circuit continuously monitors the baseline and generates compensating signals to counteract these harmful effects in advance, thereby improving measurement precision while addressing noise susceptibility at its source

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The patent employs feedback mechanisms through adaptive algorithms that continuously monitor the biopotential signals and adjust compensation parameters in real-time. The system uses feedback loops to detect noise patterns and dynamically adjust filtering and baseline tracking parameters, enabling the system to maintain high measurement precision while adapting to varying noise conditions

Inventive Principle:

Principle #23Feedback

2Productivity

If machine-learning models are used to process biopotential signals, then signal processing capability is improved, but power consumption increases

Engineering Contradiction:

Improvesignal processing capabilityVSAvoidpower consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent segments the signal processing function into two distinct parts: an analog front-end that performs initial signal conditioning, filtering, and baseline tracking, and a digital machine-learning component that performs higher-level analysis. This segmentation allows the system to handle routine noise rejection and baseline compensation in the low-power analog domain, reserving the high-power digital processing only for complex pattern recognition and classification tasks, thereby reducing overall power consumption while maintaining processing capability

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediate adaptive baseline tracking and filtering stage between the analog signal acquisition and the digital machine-learning processing. This intermediary component pre-processes the signals to remove dominant noise patterns and baseline drift, providing cleaner input to the machine-learning models and reducing their computational burden, thus lowering power consumption while preserving essential processing capability

Inventive Principle:

Principle #24Intermediary (Mediator)

3Power

If analog circuit is used to amplify biopotential signals, then signal amplification is achieved, but noise amplification also occurs

Engineering Contradiction:

Improvesignal amplificationVSAvoidnoise amplification

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by implementing adaptive baseline tracking and noise compensation circuits in the analog front-end that operate before the main signal amplification stage. These preliminary circuits continuously monitor and compensate for baseline wandering and low-frequency noise, ensuring that when the main amplifier gains the biopotential signal, the harmful low-frequency noise components have already been reduced, thereby achieving signal amplification without proportional noise amplification

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20250373238A1Techniques for filtering aggressor signals from biopotential signals, and circuits implementing the techniques

Publication Date: 2025.12.04 META PLATFORMS TECHNOLOGIES LLC

AI summary

The various implementations described herein include techniques and apparatuses for multi-channel biopotential signal acquisition, biopotential signal pre-processing, and adaptive signal conditioning. In one aspect, an analog frontend circuit includes an instrumentation amplifier (INA) and an analog-to-digital circuit (ADC) in a forward signal path. A digital circuit receives input from the ADC. An adaptive baseline tracking and compensation circuit tracks and compensates moving motion artifact driven changes. A power line interference (PLI) detection and compensation circuit tracks a desired number of PLI harmonics, and magnitude, phase and frequency for the PLI harmonics in real time. A digital-to-analog converter (DAC) circuit combines output of the adaptive baseline tracking and compensation circuit and the PLI detection and compensation circuit to output an analog output. A passive filter receives the analog output and drives an analog compensation signal at an input of the INA.