Dual-Sensor Temperature Detection Circuit for ADC Noise Isolation
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Solution Overview
Problem
Existing temperature detection devices suffer from noise interference due to charge leakage when switching from opening to short-circuit operations in analog-to-digital converters, leading to inaccurate temperature readings.
Innovation Solution
A temperature detection circuit comprising two independent temperature sensors and an AD converter, where one sensor outputs an analog signal and the other outputs a digital signal, with a power supply circuit providing a constant voltage to maintain stability and reduce noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single temperature sensor is used with an AD converter, then device complexity is reduced, but measurement precision deteriorates due to noise from charge leakage during switching operations
Solution Approach 1:
The patent divides the temperature detection function into two separate channels: one dedicated to analog signal output and another to digital signal output. By segmenting the single sensor into two independent detection paths, the noise from AD converter switching operations does not affect the analog output channel, thereby maintaining high measurement precision while keeping the overall device complexity manageable through functional separation.
Solution Approach 2:
The patent extracts the analog signal path from the digital conversion process by using a separate temperature sensor dedicated to analog output. This extraction removes the harmful noise from the AD converter switching operations out of the analog signal chain, preserving measurement precision without requiring complex noise filtering or shielding mechanisms.
2Measurement precision
If charge is accumulated in the capacitor during AD conversion, then digital signal accuracy is improved, but harmful factors increase due to charge leakage to the temperature sensor during switching
Solution Approach 1:
The patent segments the temperature sensing function into two independent sensors: one exclusively for analog output and another for digital conversion. This segmentation isolates the charge accumulation and switching operations of the AD converter to the digital channel only, preventing charge leakage from affecting the analog temperature sensor and its output signal.
Solution Approach 2:
The patent extracts the digital conversion function from the analog signal path by using a separate temperature sensor dedicated to digital output. This extraction removes the source of charge leakage noise from the analog channel, allowing the AD converter to accumulate charge accurately without introducing harmful noise to the temperature measurement.
Data Source
AI summary
A temperature detection circuit includes a first temperature sensor unit that includes a temperature sensor configured to detect a temperature of a target object and that is configured to output a first analog signal indicating the detected temperature, a second temperature sensor unit that includes a temperature sensor configured to detect a temperature of the target object and that is configured to output a second analog signal indicating the detected temperature, and an AD converter configured to convert the second analog signal into a digital signal and configured to output the digital signal.