MEMS Gyroscope Sense Frequency Tracking for Offset Compensation
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Solution Overview
Problem
Microelectromechanical systems (MEMS) gyroscopes face performance changes due to environmental variations, package stresses, and aging, affecting sensitivity and offset accuracy when mounted on printed circuit boards.
Innovation Solution
Implementing sense frequency tracking methods that involve determining the sense resonant frequency of MEMS gyroscope signals, generating an input sine wave at this frequency, and injecting it into the gyroscope to facilitate sensitivity and offset compensation, using components like CMOS, amplitude regulation, and digital phase locked loops to maintain performance over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If MEMS gyroscope is mounted on customer's PCB and subjected to environmental variations, then the device can operate in real-world conditions, but the sensitivity and offset performance changes
Solution Approach 1:
The patent implements dynamic frequency tracking that continuously monitors and adjusts to changing resonant frequencies of the MEMS gyroscope. The system adapts to environmental variations (temperature, humidity, aging) by dynamically updating the drive and sense frequencies to match the current resonant peaks, thereby maintaining optimal sensitivity and offset performance despite operational condition changes.
Solution Approach 2:
The patent employs feedback mechanisms where the system continuously measures the actual resonant frequencies of the MEMS gyroscope and uses this information to adjust the drive and sense frequencies. The frequency tracking loop provides real-time feedback to compensate for performance drift, ensuring stable operation across varying environmental conditions and over the device lifetime.
2Manufacturing precision
If conventional MEMS gyroscope trimming is performed, then initial sensitivity and offset accuracy can be met, but performance changes after mounting and environmental exposure
Solution Approach 1:
The patent performs preliminary frequency characterization and trimming adjustments before the MEMS gyroscope is mounted in the final application. By pre-adjusting the drive and sense frequencies to match the actual resonant peaks and pre-compensating for anticipated environmental drift, the system establishes accurate baseline performance that maintains stability over time and across operating conditions.
Solution Approach 2:
The patent systematically varies and adjusts critical parameters including drive frequency, sense frequency, and trim coefficients to optimize performance. The system characterizes the MEMS gyroscope across a range of frequencies and environmental conditions, then selects and locks in the optimal parameter set that maximizes sensitivity and minimizes offset drift over the device lifetime.
3Reliability
If frequency tracking and compensation circuitry is added, then sensitivity and offset performance can be maintained, but device complexity increases
Solution Approach 1:
The patent integrates multiple functions into unified circuit blocks that perform both frequency measurement and compensation tasks. The same circuitry used for initial characterization is reused for ongoing frequency tracking and adjustment, eliminating the need for separate dedicated components and reducing overall system complexity while maintaining performance consistency.
Solution Approach 2:
The MEMS gyroscope system performs its own frequency characterization and compensation without requiring external testing equipment or manual intervention. The integrated circuits automatically measure resonant frequencies, calculate appropriate trim adjustments, and apply compensation, enabling the device to self-correct performance drift and maintain optimal operation autonomously.
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 enables continuous monitoring and adjustment of MEMS gyroscope sensitivity and offset performance, effectively compensating for changes caused by environmental factors and ensuring consistent operation over the device's lifetime.
Implementation Method 1
determining a sense resonant frequency (e.g., sense resonant frequency at the sense peak of the MEMS gyroscope) of the sense signal
Implementation Method 2
generating an input sine wave with a frequency of the sense resonant frequency of the sense signal injecting the input sine wave into the MEMS gyroscope
Data Source
AI summary
Microelectromechanical systems (MEMS) gyroscopes and related sense frequency tracking techniques are described. Various embodiments facilitate sense frequency tracking and offset and/or sensitivity change compensation. Exemplary embodiments can comprise receiving a sense signal at an output of a MEMS gyroscope and determining a sense resonant frequency of the sense signal. In addition, exemplary methods can comprise generating an input sine wave with a frequency of the sense resonant frequency of the sense signal injecting the input sine wave into the MEMS gyroscope, to facilitate sense frequency tracking.