Biometric Electrode Switching for Low-Power Offset-Stable Sensing

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Solution Overview

Problem

Existing wearable devices face challenges in acquiring and monitoring biometric electrical signals due to power consumption issues and unstable potential offsets at the skin/electrode junction, particularly when using dry electrodes with high capacitive materials, which are aesthetically desirable but inefficient with DC current and require more power with AC current.

Innovation Solution

A device with switchable DC and AC current supplies and capacitive coupling, allowing for efficient data acquisition by alternating between idle and active modes, using a wider range of electrode materials while minimizing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If dry electrodes with high capacitive materials are used, then aesthetic appearance is improved, but power consumption increases and potential offsets become unstable

Engineering Contradiction:

Improveaesthetic appearanceVSAvoidpower consumption

Core Design Contradiction:

ShapeVSUse of energy by moving object

Solution Approach 1:

The patent applies periodic action by switching between AC and DC current modes. AC current is used periodically to detect skin contact and clear potential offsets, while DC current is used for normal low-power operation. This periodic switching allows the system to maintain aesthetic dry electrodes with high capacitive materials while managing power consumption and offset stability through timed AC bursts rather than continuous AC operation.

Inventive Principle:

Principle #19Periodic action

2Measurement precision

If AC current is used to clear potential offsets, then measurement precision is improved, but power consumption increases

Engineering Contradiction:

Improvepotential offset stabilityVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system uses periodic AC current bursts rather than continuous AC operation. The controller switches to AC mode only when needed to detect skin contact or clear potential offsets, then returns to low-power DC mode for normal operation. This periodic application of AC current maintains measurement precision by clearing offsets when necessary while dramatically reducing overall power consumption compared to continuous AC operation.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent changes the electrical parameter (current type) dynamically based on operational needs. The controller switches between AC and DC current modes, changing the electrical parameter from static to dynamic. This allows the system to use AC current's ability to clear potential offsets only when needed, rather than continuously, thereby maintaining measurement precision while reducing power consumption.

Inventive Principle:

Principle #35Parameter changes

3Use of energy by moving object

If DC current is used for continuous operation, then power consumption is reduced, but skin contact detection becomes less reliable

Engineering Contradiction:

Improvepower consumptionVSAvoidskin contact detection

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The system periodically switches to AC current mode to detect skin contact, rather than relying solely on DC current. The controller implements a sequence where AC current is applied periodically to sense skin contact through the electrodes, then switches back to DC current for low-power operation. This periodic AC detection maintains reliable skin contact detection while minimizing the time AC current is applied, thus reducing overall power consumption.

Inventive Principle:

Principle #19Periodic action

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 enables effective biometric signal acquisition with reduced power drain by utilizing a variety of electrode materials, maintaining low potential offsets, and optimizing battery life in wearable devices.

Implementation Method 1

AC-coupled data acquisition which overcomes the potential offset at the skin/electrode junction

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Implementation Method 2

transmit the resultant mediated biopotential signals from the skin surface to the biometric data acquisition module

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS12564347B2Device, system and method for acquiring and monitoring of biometric electrical signals

Publication Date: 2026.03.03 B SECUR LTD

AI summary

There is provided a device for acquiring biometric electrical signals comprising at least two electrodes. The device also comprises a current supply comprising a direct current supply, an alternating current supply, and a switch actuatable to switch selectively between the direct current supply and the alternating current supply. The device further comprises a capacitive coupling to couple each electrode to the current supply, a direct coupling to couple each electrode to the current supply, and a switch actuatable to switch selectively between the direct coupling and the capacitive coupling. The device also comprises a data acquisition module.