Dual-ADC Temperature Sensing for Low-Power Change Detection

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Solution Overview

Problem

Existing low power temperature sensing methods consume excessive energy due to constant sampling with high precision analog-to-digital converters, even when temperature remains stable, and struggle to detect rapid changes efficiently.

Innovation Solution

A method and circuit that utilize two ADCs, where a high precision ADC is used initially for accurate temperature measurement and an ultra-low power ADC for continuous monitoring of temperature changes, activating the high precision ADC only when significant changes occur, thereby reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a high precision ADC is used for continuous temperature sampling, then measurement precision is improved, but power consumption increases

Engineering Contradiction:

Improvetemperature measurement precisionVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent divides the temperature sensing system into two separate ADC components: a first ADC for initial high-precision temperature measurement and a second ADC for subsequent low-power monitoring. This segmentation allows each ADC to be optimized for its specific function, with the second ADC consuming significantly less power while maintaining adequate measurement precision for detecting temperature changes within a predefined range.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic switching between two ADCs based on operational requirements. The system transitions from using the high-precision first ADC to the low-power second ADC after the initial measurement, and can switch back to the first ADC when temperature changes exceed the predefined range. This dynamic adaptation optimizes power consumption while maintaining measurement precision when needed.

Inventive Principle:

Principle #15Dynamics

2Use of energy by moving object

If a low power ADC is used for continuous monitoring, then power consumption is reduced, but the ability to detect rapid temperature changes is impaired

Engineering Contradiction:

Improvepower consumptionVSAvoidtemperature change detection speed

Core Design Contradiction:

Use of energy by moving objectVSSpeed

Solution Approach 1:

The patent employs a feedback mechanism where the second ADC continuously monitors temperature and compares changes against a predefined range. When temperature changes exceed this range, the system receives feedback to switch back to the first high-precision ADC, ensuring rapid detection and accurate measurement of significant temperature changes while maintaining low power consumption during stable conditions.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically switches between ADCs based on temperature stability. The second low-power ADC operates during stable temperature conditions, and the system transitions to the first high-precision ADC when rapid temperature changes are detected, thereby adapting the detection capability to the actual thermal conditions.

Inventive Principle:

Principle #15Dynamics

3Use of energy by moving object

If high precision ADC is activated only when temperature changes significantly, then power consumption is reduced, but measurement continuity may be affected

Engineering Contradiction:

Improvepower consumptionVSAvoidmeasurement continuity

Core Design Contradiction:

Use of energy by moving objectVSDuration of action of stationary object

Solution Approach 1:

The patent ensures continuous temperature monitoring by maintaining the second ADC in an active state throughout operation. Although the second ADC has lower precision, it continuously provides temperature data within the predefined range, ensuring no gaps in monitoring. The first ADC is activated on-demand when significant changes occur, maintaining overall measurement continuity while optimizing power consumption.

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentUS11835398B2Method and circuit for temperature sensing, temperature sensor and electrical appliance

Publication Date: 2023.12.05 SCIOSENSE BV

AI summary

In an embodiment a method includes providing an analog signal having a first value of a temperature of an object, performing an analog-to-digital conversion of the analog signal using a first analog-to-digital converter (ADC) thereby providing a first digital signal representing an initial digital temperature value, performing an analog-to-digital conversion of the analog signal using a second ADC thereby providing a second digital signal representing a digital reference temperature value, regularly providing the analog signal having a successive value of the temperature of the object, performing the analog-to-digital conversion of the analog signal using the second ADC thereby providing the second digital signal representing a successive digital temperature value, calculating a digital delta temperature value according to a difference between the successive digital temperature value and the digital reference temperature value and repeating portions of the method as long as the digital delta temperature value lies within a predefined range.