Dual-ADC Temperature Sensor Circuit for Low-Power Change Tracking
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Solution Overview
Problem
Existing low power temperature sensing methods consume excessive energy due to constant sampling with high precision ADCs, 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, restarting the process only when significant changes occur, thereby reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high precision ADC is used for constant temperature sampling, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent segments the temperature sensing system into two distinct ADC components: a first ADC optimized for high precision measurement and a second ADC optimized for low power consumption. These two ADCs work in coordinated fashion, with the first ADC performing initial accurate measurements and the second ADC performing subsequent monitoring, thereby dividing the measurement task to balance precision and power consumption requirements
Solution Approach 2:
The patent implements dynamic switching between two ADCs based on measurement needs. The system transitions from using the high-precision first ADC to the low-power second ADC after initial measurement, and can switch back when temperature changes exceed a threshold. This dynamic adaptation allows the system to maintain measurement quality while minimizing power consumption during stable temperature conditions
2Measurement precision
If a high precision ADC is used for continuous monitoring, then detection accuracy is improved, but response time to detect temperature changes worsens
Solution Approach 1:
The patent performs preliminary accurate temperature measurement using the first high-precision ADC before switching to the second ADC. This preliminary action establishes a reference temperature value that enables subsequent rapid detection of temperature changes by the second ADC, combining the accuracy of initial measurement with the speed of continuous monitoring
Data Source
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AI summary
In an embodiment a method for temperature sensing comprises the steps of feeding an analog signal (Sin) comprising a first value of a temperature of an object, performing (S1) an analog-to-digital conversion of the analog signal using a first analog-to-digital converter (10), ADC, and therefrom providing a first digital signal (Sout1) representing an initial digital temperature value, performing (S2) an analog-to-digital conversion of the analog signal (Sin) using a second ADC (20) and therefrom providing a second digital signal (Sout2) representing a digital reference temperature value, regularly feeding the analog signal (Sin) comprising a successive value of the temperature of the object, performing (S3) an analog-to-digital conversion of the analog signal (Sin) using the second ADC (20) and therefrom providing the second digital signal (Sout2) representing a successive digital temperature value, and calculating a digital delta temperature value according to a difference between the successive digital temperature value and the digital reference temperature value, and repeating the latter step as long as the digital delta temperature value lies within the predefined range