Heat Flow Sensor Offset Correction Across Multiple Gain Ranges

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Solution Overview

Problem

Heat flow sensors experience output value drift over time, making it difficult to perform reference value correction and maintain a wide dynamic range of output values due to the limitations of single offset correction coefficients in existing configurations.

Innovation Solution

An output device for heat flow sensors that includes an offset value calculation part to calculate offset values for multiple gain magnifications, an amplification part to amplify the output value by a selected gain magnification, and an offset part to subtract the corresponding offset value, allowing for dynamic range widening and reference value correction, with optional updating of offset values based on average digital values and gain magnification changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single offset correction coefficient is applied to output data in a wide dynamic range, then the device complexity is reduced, but the reference value correction of the sensor output data cannot be performed

Engineering Contradiction:
Improvecorrection circuit complexityVSAvoidreference value correction accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent divides the correction process into multiple segments by calculating separate offset correction coefficients for different gain magnification ranges. The correction circuit selects and applies the appropriate offset coefficient based on the current gain magnification, enabling accurate reference value correction across the entire wide dynamic range while maintaining manageable circuit complexity through modular correction stages.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If the gain magnification is increased to widen the dynamic range, then the measurement range is expanded, but the output value drift and saturation occur more easily

Engineering Contradiction:
Improvedynamic rangeVSAvoidoutput value stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements dynamic adjustment of gain magnification based on the detected light intensity levels. The correction circuit automatically switches between different gain magnifications and applies corresponding offset correction coefficients, allowing the system to adapt to varying input conditions and maintain reliable, drift-free measurements across the entire dynamic range without saturation.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If multiple offset correction coefficients are calculated for different gain magnifications, then the reference value correction is improved, but the device complexity increases

Engineering Contradiction:
Improvereference value correction accuracyVSAvoidcorrection circuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The correction circuit is designed with multi-functionality to handle multiple gain magnifications and their corresponding offset correction coefficients within a single integrated structure. The circuit selectively applies the appropriate offset coefficient based on the current gain magnification, achieving accurate reference value correction across all ranges while avoiding the need for completely separate correction circuits for each gain level.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3490143B1Output device for heat flow sensor and output method for heat flow sensor
Publication Date: 2021.02.17 OMRON CORP
  • EP3490143B1 patent drawingFigure 1
  • EP3490143B1 patent drawingFigure 2
  • EP3490143B1 patent drawingFigure 3

AI summary

An output device for a heat flow sensor (100) includes an offset value calculation part (41) configured to calculate an offset value for each gain magnification regarding a plurality of gain magnifications (GM1, GM2, GM3, GM4), an amplification part (10) configured to amplify an output value of a heat flow sensor (HS) by a first gain magnification among the plurality of gain magnifications (GM1, GM2, GM3, GM4), an offset part (20) configured to subtract the offset value corresponding to the first gain magnification from the amplified output value, and an A/D converter (30) configured to convert the output value after subtraction thereof into a digital value.