MEMS Oscillator Temperature Feedback for Frequency Compensation
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Solution Overview
Problem
High precision timing devices face challenges in accurately reporting temperature and compensating for temperature-dependent frequency offsets, which affects the stability and accuracy of timing signals in microelectromechanical systems (MEMS) resonators.
Innovation Solution
Integration of a MEMS resonator and temperature transducer within a small form-factor integrated circuit (IC) package that outputs both timing signals and temperature data, enabling temperature-specific frequency compensation by providing coefficients for polynomial expressions or direct frequency correction values, thus allowing for temperature-compensated timing signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a MEMS resonator is used for timing signals, then the device achieves small form factor and integration capability, but temperature-dependent frequency offset reduces timing accuracy
Solution Approach 1:
The patent implements a feedback mechanism where the resonator temperature is continuously measured by a temperature transducer and this temperature information is fed back to a compensation circuit. The compensation circuit uses the temperature data to calculate and apply frequency correction values to the resonator drive signal, thereby compensating for temperature-dependent frequency offsets and maintaining timing accuracy across varying temperatures.
Solution Approach 2:
The patent changes the operating parameters of the MEMS resonator by dynamically adjusting its drive frequency based on temperature measurements. A polynomial expression relating frequency offset to temperature is used to determine correction values, which are then applied to modify the resonator's operating frequency in real-time, compensating for temperature-induced frequency drift.
2Measurement precision
If temperature compensation is implemented using polynomial expressions, then frequency accuracy is improved, but device complexity increases
Solution Approach 1:
The patent performs preliminary characterization of the resonator's temperature-frequency relationship during manufacturing, determining polynomial coefficients that describe the frequency offset as a function of temperature. These pre-determined coefficients are stored in the device and used during operation to calculate compensation values, eliminating the need for complex real-time analysis and simplifying the compensation circuitry.
Solution Approach 2:
The patent introduces a polynomial expression as an intermediary mathematical model that simplifies the relationship between temperature and frequency offset. By using this predetermined polynomial model, the complex physical relationship is converted into a simple calculation using stored coefficients, reducing the computational complexity required in the compensation circuit while maintaining high frequency accuracy.
3Stability of the object's composition
If temperature tracking is performed during rapid temperature changes, then timing stability is maintained, but response time requirements increase
Solution Approach 1:
The patent implements periodic temperature measurement and compensation updates, where the temperature transducer continuously monitors the resonator temperature at regular intervals. This periodic action ensures that temperature changes are detected and compensated for in a timely manner, maintaining timing stability during rapid temperature transitions without requiring continuous real-time processing that would increase system complexity.
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 solution ensures accurate tracking of resonator temperature and precise frequency compensation, even during rapid temperature changes, enhancing the stability and accuracy of timing signals in MEMS-based systems.
Implementation Method 1
a MEMS resonator and temperature transducer are integrated within a small form-factor integrated circuit (IC) package that outputs both a timing signal according to mechanical vibration of the MEMS resonator
Implementation Method 2
a MEMS resonator and temperature transducer—aregenerally a temperature-to-digital converter (TDC)—are integrated within a small form-factor integrated circuit (IC) package
Data Source
AI summary
In an integrated circuit device having a microelectromechanical-system (MEMS) resonator and a temperature transducer, a clock signal is generated by sensing resonant mechanical motion of the MEMS resonator and a temperature signal indicative of temperature of the MEMS resonator is generated via the temperature transducer. The clock signal and the temperature signal are output from the integrated circuit device concurrently.