Electrochemical Cell Impedance Circuit Using Chirp Signal Separation

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Solution Overview

Problem

Electrochemical sensors face limitations in signal-to-noise ratio (SNR) due to their inherent non-linearity, which is addressed by extending acquisition times at the cost of increased power consumption, particularly in battery-powered devices.

Innovation Solution

The use of a chirp signal to separate linear and non-linear components of the output signal through deconvolution, allowing for increased stimulus amplitude without distorting the measured response, thereby improving SNR and reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If acquisition time is extended to improve SNR, then signal-to-noise ratio is improved, but power consumption increases

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent changes the parameter of stimulus amplitude from low (conventional EIS) to high amplitude, enabling faster measurements with improved SNR. This is combined with signal separation techniques to handle the non-linear effects of high amplitude stimulation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent segments the output signal into linear and non-linear components using deconvolution and harmonic analysis. This allows the system to extract the linear impedance information while discarding the non-linear distortion components, enabling high amplitude stimulation without measurement degradation.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If stimulus amplitude is increased to improve SNR, then signal-to-noise ratio is improved, but non-linear distortion increases

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidnon-linear distortion

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful non-linear distortion into useful information by analyzing harmonic components. The non-linear distortion manifests as specific harmonic frequencies that can be identified and separated from the linear response, allowing the system to extract pure impedance information while utilizing the high amplitude stimulus.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent introduces signal processing techniques (deconvolution, harmonic analysis) as intermediaries between the high amplitude stimulus and the impedance measurement. These intermediaries filter out the non-linear distortion and extract the linear impedance response, enabling high amplitude stimulation without measurement degradation.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Volume of moving object

If device size is reduced for wearable applications, then portability is improved, but measurement accuracy may deteriorate

Engineering Contradiction:

Improvedevice sizeVSAvoidmeasurement accuracy

Core Design Contradiction:

Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent enables continuous or frequent impedance measurements by reducing acquisition time through high amplitude stimulation. This allows wearable devices to continuously monitor electrochemical cell conditions without significant power consumption, maintaining measurement accuracy while enabling compact design.

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentUS20260092979A1Circuitry for measurement of electrochemical cells

Publication Date: 2026.04.02 CIRRUS LOGIC INT SEMICON LTD

AI summary

Circuitry for determining an impedance of an electrochemical cell comprising at least one first electrode and a second electrode, the circuitry comprising: drive circuitry configured to apply a stimulus to the electrochemical cell, the stimulus having a stimulation frequency and a stimulation amplitude; and measurement circuitry configured to: measure an output of the electrochemical cell to generate an output signal; separate the output signal into a linear component and a non-linear component; and determine the impedance of the cell based on the linear component of the response.