Oscillation Measurement Circuit Using TAF-FLL for Precise Temperature Sensing
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Solution Overview
Problem
Current temperature sensing methods, such as thermocouples and resistance sensing, face challenges like complex signal processing, susceptibility to corrosion, poor noise resistance, and difficulty in measuring resistance values in electronic systems, limiting their precision, functionality, and reliability in the context of increasing demands for high-precision, multi-functional, low-power, and cost-effective sensors in the Internet of Things era.
Innovation Solution
A measuring device incorporating an oscillation circuit, a time average frequency-frequency lock loop (TAF-FLL), and a digital signal processing circuit, which outputs a frequency control word correlated with the oscillation frequency, allowing for precise measurement of element values like resistance, capacitance, or inductance, and temperature through digital signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermocouple method is used for temperature measurement, then measurement range is wide and it is not affected by intermediate medium, but signal processing is complex and noise resistance is poor
Solution Approach 1:
The patent replaces the traditional thermocouple method with an oscillation circuit-based measurement system. The thermocouple's direct contact measurement is substituted by an oscillation circuit that converts temperature-dependent resistance changes into frequency changes, eliminating the need for complex signal processing and improving noise resistance through frequency-domain measurement.
Solution Approach 2:
The patent changes the measurement parameter from voltage (thermocouple) or resistance (RTD) to frequency. By using an oscillation circuit where the oscillation frequency is determined by the resistance of the temperature sensor, the measurement is transformed into a frequency measurement, which is more resistant to noise and does not require complex signal processing.
2Ease of operation
If resistance sensing method is used, then measurement is straightforward, but resistance values are difficult to measure and use in electronic systems
Solution Approach 1:
The patent replaces direct resistance measurement with frequency measurement using an oscillation circuit. The oscillation frequency is determined by the resistance value, but the output is a frequency signal that can be easily processed by digital electronics, microcontrollers, and communication interfaces, greatly improving adaptability to electronic systems.
Solution Approach 2:
The patent transforms the resistance parameter into a frequency parameter through the oscillation circuit. This allows the temperature sensor to output a frequency signal that can be directly interfaced with digital systems, eliminating the need for complex resistance-to-digital conversion and improving ease of integration.
3Reliability
If traditional temperature sensing methods are used, then basic measurement function is achieved, but power consumption is high and functionality is limited
Solution Approach 1:
The patent uses periodic oscillation to perform measurements. The oscillation circuit naturally oscillates at a frequency determined by the temperature sensor, allowing for periodic sampling and measurement without requiring continuous power-intensive operations. This reduces average power consumption while maintaining measurement reliability.
Solution Approach 2:
The patent creates a multi-functional temperature sensor that can provide not only temperature measurement but also frequency output for communication, timing, and other functions. This universal approach reduces the need for separate components, lowering overall system power consumption while enhancing reliability.
Data Source
AI summary
A measuring device and a measuring method are provided. The measuring device includes an oscillating circuit, a time average frequency-frequency lock loop, and a digital signal processing circuit. The oscillation circuit includes an element to be measured and is configured to output a signal having an oscillation frequency correlated with an element value of the element to be measured. The time average frequency-frequency lock loop is configured to receive the signal output by the oscillation circuit and output a frequency control word correlated with the oscillation frequency. The digital signal processing circuit is configured to read the frequency control word output by the time average frequency-frequency lock loop and obtain the element value of the element to be measured according to the read frequency control word. The measuring device is easy to integrate, has small volume, low power consumption, and high reliability, and can achieve high-precision measurement.