Voltage Ratio Temperature Detection Circuit
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Solution Overview
Problem
Existing temperature detection circuits face challenges in achieving high accuracy due to variations in resistance element characteristics, which are influenced by manufacturing processes and temperature characteristics, leading to increased circuit size and power consumption.
Innovation Solution
A circuit apparatus that uses a voltage output circuit to generate two output voltages with different temperature characteristics, an A/D conversion circuit to convert these voltages into digital values, and a processing unit for digital calculation processing to obtain accurate temperature data, reducing the influence of resistance element variations and temperature characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If resistance element characteristics are used for temperature detection, then temperature data can be obtained, but measurement precision deteriorates due to manufacturing variations and temperature characteristics
Solution Approach 1:
The patent changes the parameter from using resistance value directly to using voltage ratio. By measuring voltage V1 across the resistance element and voltage V2 across a reference resistance, and calculating the ratio V1/V2, the measurement becomes independent of the absolute resistance value. This ratio method eliminates the influence of manufacturing variations and temperature characteristics of the resistance element, thereby improving temperature detection accuracy.
2Measurement precision
If correction circuits are added to compensate for resistance element variations, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent merges the temperature detection function with the resistance element usage by introducing a reference resistance and using voltage ratio measurement. Instead of adding separate correction circuits, the solution combines the measurement of voltage across the resistance element with voltage across a reference resistance, and uses digital processing of the voltage ratio to achieve both temperature detection and compensation for resistance variations in a unified approach.
Solution Approach 2:
The patent replaces analog correction circuits with digital calculation processing. By converting the voltage ratio measurement into a digital value and performing temperature calculation through digital processing, the system eliminates the need for complex analog correction circuits while maintaining high measurement precision. This substitution of digital processing for analog circuit correction simplifies the overall device structure.
3Measurement precision
If additional resistance elements are provided to reduce temperature characteristics, then measurement precision improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes from relying on matching resistance element characteristics to using a voltage ratio measurement approach. By measuring the ratio of voltage V1 across the resistance element to voltage V2 across a reference resistance, the system becomes independent of the absolute resistance values and their matching characteristics. This eliminates the need for high manufacturing precision in resistance element matching while maintaining temperature detection accuracy.
Data Source
AI summary
A circuit apparatus includes a voltage output circuit that outputs a first output voltage when a first current of first temperature characteristics flows in a resistance element, and a second output voltage when a second current of second temperature characteristics different from the first temperature characteristics flows in the resistance element, an A/D conversion circuit that outputs a first digital value by performing A/D conversion on the first output voltage, and outputs a second digital value by performing A/D conversion on the second output voltage, and a processing unit that obtains temperature data by digital calculation processing of the first digital value and the second digital value.