Dual-Resonator Temperature Sensing With Frequency-Ratio Oversampling
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Solution Overview
Problem
Current temperature sensing technologies face challenges in achieving high resolution and low power consumption while maintaining energy efficiency and stability across a broad temperature range.
Innovation Solution
The development of a dual-resonator temperature sensor utilizing a pair of oscillators with different temperature coefficients and a frequency ratio engine that oversamples and decimates clock signals to generate a digital temperature-sense output, enabling temperature resolution as low as 20 μK at high bandwidths with low power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If current temperature sensing technologies are used, then temperature measurement capability is provided, but energy efficiency is insufficient and power consumption is high
Solution Approach 1:
The patent changes the operating parameters of the oscillators by utilizing devices with different quality factors (Q1 and Q2) and different temperature coefficients of frequency (TCF1 and TCF2). By operating the oscillators at different frequencies (f1 and f2) and processing their frequency difference or ratio, the system achieves high-resolution temperature sensing with improved energy efficiency compared to traditional single-oscillator approaches.
2Measurement precision
If high resolution temperature sensing is achieved, then temperature resolution improves, but bandwidth decreases
Solution Approach 1:
The patent implements a dynamic measurement approach where the system can adaptively adjust the measurement bandwidth based on the desired resolution. By using digital signal processing techniques on the oscillator output signals and implementing configurable filtering and averaging, the system achieves 20 μK resolution at 100 Hz bandwidth, demonstrating dynamic optimization between resolution and speed.
3Measurement precision
If temperature resolution is increased to 20 μK, then measurement precision improves, but power dissipation increases
Solution Approach 1:
The patent segments the temperature sensing function into two parallel oscillator circuits with different characteristics, allowing independent optimization of each device. This segmentation enables the system to achieve high resolution through frequency comparison rather than requiring a single high-power precision oscillator, resulting in power dissipation of less than 19 mW at 20 μK resolution.
4Measurement precision
If frequency ratio engine oversampling is implemented, then temperature resolution improves, but device complexity increases
Solution Approach 1:
The patent replaces complex analog frequency multiplication and division circuits with a digital frequency ratio engine that uses straightforward counting and division operations. The frequency ratio engine processes the oscillator outputs through digital logic to compute the ratio f1/f2 or difference f1-f2, achieving high resolution temperature measurement with reduced circuit complexity and improved integrability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach results in a temperature sensor with improved energy efficiency, achieving resolution as low as 20 μK at 100 Hz bandwidths with power dissipation of less than 19 mW and frequency stability of 100 ppb over -45°C to +105°C, outperforming previous technologies by more than an order of magnitude in energy efficiency.
Implementation Method 1
a first oscillator generating a first clock signal having a first frequency and a first temperature coefficient of frequency and a second oscillator generating a second clock signal having a second frequency and a second temperature coefficient of frequency
Implementation Method 2
a first resonator having a first quality factor and a second resonator having a second quality factor
Data Source
AI summary
In a high resolution temperature sensor, first and second MEMS resonators generate respective first and second clock signals and a locked-loop reference clock generator generates a reference clock signal having a frequency that is phase-locked to at least one of the first and second clock signals. A frequency-ratio engine within the MEMS temperature sensor oversamples at least one of the first and second clock signals with the reference clock signal to generate a ratio of the frequencies of the first and second clock signals.