Electrochemical Cell Measurement Circuit with Analog Signal Linearization

Solution Overview

Problem

Electrochemical sensors face challenges in accurately measuring analyte concentrations at high levels due to the non-linear response of ion-selective electrodes, requiring high-resolution analog-to-digital converters that increase complexity, cost, and energy consumption.

Innovation Solution

The introduction of circuitry that includes non-linear compensation elements such as diodes, bipolar junction transistors, and field effect transistors to linearize the potential difference signals in the analog domain before digitization, reducing the burden on downstream processing and improving efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high-resolution analog-to-digital converters are used to track small changes in potential at high analyte concentrations, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improvemeasurement precisionVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by linearizing the non-linear potential response of the ion-selective electrode through analog circuitry (using operational amplifiers and resistors configured to produce a linear output signal) before the signal reaches the analog-to-digital converter. This preprocessing transformation converts the logarithmic relationship between potential and concentration into a linear relationship, allowing standard-resolution ADCs to accurately measure both high and low analyte concentrations without requiring high-resolution converters.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If high-resolution analog-to-digital converters are used to track small changes in potential at high analyte concentrations, then measurement precision is improved, but energy consumption increases

Engineering Contradiction:

Improvemeasurement precisionVSAvoidenergy consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies preliminary action by linearizing the non-linear potential response of the ion-selective electrode through analog circuitry (using operational amplifiers and resistors configured to produce a linear output signal) before the signal reaches the analog-to-digital converter. This preprocessing transformation converts the logarithmic relationship between potential and concentration into a linear relationship, allowing standard-resolution ADCs to accurately measure both high and low analyte concentrations without requiring high-resolution converters, thereby reducing energy consumption.

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If high-resolution analog-to-digital converters are used to track small changes in potential at high analyte concentrations, then measurement precision is improved, but manufacturing cost increases

Engineering Contradiction:

Improvemeasurement precisionVSAvoidmanufacturing cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by linearizing the non-linear potential response of the ion-selective electrode through analog circuitry (using operational amplifiers and resistors configured to produce a linear output signal) before the signal reaches the analog-to-digital converter. This preprocessing transformation converts the logarithmic relationship between potential and concentration into a linear relationship, allowing standard-resolution ADCs to accurately measure both high and low analyte concentrations without requiring high-resolution converters, thereby reducing manufacturing cost.

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

This approach allows for accurate measurement of analyte concentrations across a wide range while reducing the complexity and energy consumption of the measurement system, enhancing the efficiency of electrochemical cell characterization.

Implementation Method 1

measured potential difference varies logarithmically with analyte concentration

Methodology Applied

Scientific EffectLogarithmic response characteristic of ion-selective electrode:

Implementation Method 2

the response characteristic of the compensation circuitry may be an exponential response characteristic

Methodology Applied

Scientific EffectExponential response characteristic of compensation circuitry:

Data Source

PatentUS20240175844A1Circuitry for measurement of electrochemical cells

Publication Date: 2024.05.30 CIRRUS LOGIC INC

AI summary

Circuitry for characterising an electrochemical cell having a first electrode, a second electrode and a non-linear response characteristic, the circuitry comprising: difference circuitry configured to measure a potential difference across the electrochemical cell and output a difference voltage proportional to the measured potential difference; compensation circuitry configured to linearise the difference voltage and output a linearised difference signal; and a first analog-to-digital converter (ADC) configured to convert the linearised difference signal to a digital output.