Mixer-Based Lead-On Detection Circuit for Dry Electrode Accuracy

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Solution Overview

Problem

Small dry electrodes in portable medical devices suffer from high impedance, leading to detection errors in lead-on detection procedures due to power line common mode interference and electrode tissue offset, causing inaccurate contact detection and increased power consumption.

Innovation Solution

A lead-on detection circuitry with a mixer-based receiver and duty-cycle controller that generates specific clock signals to accurately determine electrode contact with the body, using a transmitting signal and mixer-based receiver to generate output signals, and enabling/disabling components based on a slower clock signal to reduce power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If small dry electrodes are used in portable medical devices, then the device portability and comfort are improved, but the electrode impedance increases causing detection errors

Engineering Contradiction:
ImproveportabilityVSAvoiddetection accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent introduces a lead-on detection circuitry as an intermediary component between the small dry electrodes and the physiological information detection circuitry. This circuitry actively detects electrode-skin contact status and generates trigger signals to control the enabling/disabling of the main detection circuitry, preventing detection errors caused by high electrode impedance while maintaining the use of small portable electrodes.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements preliminary detection action by continuously monitoring electrode contact status through the lead-on detection circuitry before enabling the physiological information detection. The system performs lead-on detection in advance to determine whether electrodes are properly attached to the skin, and only enables the main detection circuitry when contact is confirmed, thereby preventing measurement errors from the outset.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If the lead-on detection circuitry is always enabled to detect electrode contact, then the detection accuracy is improved, but the power consumption increases

Engineering Contradiction:
Improvecontact detection accuracyVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic action by controlling the lead-on detection circuitry to operate in alternating enable and disable states based on detected contact status. When electrode-skin contact is detected, the circuitry enables the physiological information detection circuitry and can subsequently reduce its activity, creating a periodic operational pattern that maintains detection accuracy while reducing overall power consumption during sustained monitoring.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies dynamics by making the operational state of the detection circuitry adaptive rather than static. The system dynamically transitions between enable and disable states based on real-time detection of electrode contact status, allowing the circuitry to be always ready when needed while conserving power during non-detection phases, thus resolving the contradiction between continuous monitoring and power consumption.

Inventive Principle:
Principle #15Dynamics

3Use of energy by moving object

If the physiological information detection circuitry is disabled to lower power consumption, then the energy efficiency is improved, but the response time to detect physiological signals increases

Engineering Contradiction:
Improvepower consumptionVSAvoidresponse time
Core Design Contradiction:
Use of energy by moving objectVSLoss of time

Solution Approach 1:

The patent applies preliminary action by implementing a lead-on detection circuitry that continuously or periodically monitors electrode contact status before enabling the physiological information detection circuitry. This preliminary detection ensures that when the main circuitry is enabled, it is immediately ready to detect physiological signals without delay, thus maintaining fast response time while allowing the circuitry to remain disabled during periods when no contact is detected, thereby conserving power.

Inventive Principle:
Principle #10Preliminary 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 effectively reduces power consumption and improves accuracy in detecting electrode contact with the human body, minimizing detection errors and power line interference, while maintaining low power usage.

Implementation Method 1

The mixer-based receiver is configured to perform a mixing operation based on the first clock signal and the transmitting signal to generate an output signal

Methodology Applied
Scientific EffectMixing operation: Heterodyne

Data Source

PatentEP3851035B1Lead-on detection circuitry of biopotential acquisition system
Publication Date: 2023.05.10 MEDIATEK INC
  • EP3851035B1 patent drawingFigure 1
  • EP3851035B1 patent drawingFigure 2
  • EP3851035B1 patent drawingFigure 3

AI summary

The present invention provides a lead-on detection circuitry of a biopotential acquisition system. The lead-on detection circuitry includes an input terminal, a duty-cycle controller, a transmitting signal generator and a mixer-based receiver. The duty-cycle controller is configured to generate a first clock signal. The transmitting signal generator is configured to generate a transmitting signal to the input terminal according to the first clock signal. The mixer-based receiver is configured to perform a mixing operation based on the first clock signal and the transmitting signal to generate an output signal, wherein the output signal indicates if an electrode of the biopotential acquisition system is in contact with a human body, and the electrode is coupled to the input terminal.