MEMS Gyroscope Gain Circuit for Quality Factor Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fluctuations in temperature or outgassing/ingassing cause pressure changes in MEMS resonators, leading to changes in the quality factor, which affect the zero-rate offset and phase error in MEMS gyroscope devices, especially in frequency-mismatched systems.
Innovation Solution
A gain circuit is implemented in MEMS gyroscope systems to receive digitized drive signals and determine percentage changes in quality factor, using stored trim values to compensate for these changes, thereby adjusting the output signals to maintain accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure changes occur in the MEMS resonator cavity due to temperature fluctuations or outgassing/ingassing, then the quality factor of the MEMS resonator changes, but this results in changes in zero-rate offset and phase error
Solution Approach 1:
The patent implements a feedback mechanism where the system continuously monitors the quality factor of the MEMS resonator and automatically adjusts compensation parameters based on detected changes. The processor determines quality factor variations and applies corresponding corrections to the zero-rate offset, creating a closed-loop system that maintains measurement accuracy despite environmental fluctuations.
Solution Approach 2:
The patent changes the operational parameters of the MEMS gyroscope system by dynamically adjusting compensation values based on detected quality factor changes. When the quality factor deviates from reference values, the system modifies offset compensation parameters to counteract the effects of pressure changes, thereby maintaining accurate angular rate measurements.
2Adaptability or versatility
If the quality factor of the MEMS resonator changes due to environmental conditions, then the phase difference between Coriolis and quadrature signals deviates from 90°, but this increases phase error in frequency-mismatched systems
Solution Approach 1:
The patent applies preliminary compensation by pre-determining correction values for expected quality factor variations. The system stores reference quality factor values and pre-calculated compensation parameters, allowing it to quickly apply appropriate corrections when environmental conditions change, thereby maintaining accurate phase relationships between signals.
Solution Approach 2:
The system continuously monitors the actual quality factor and compares it against reference values, then applies real-time feedback compensation to correct phase errors. This closed-loop approach ensures that phase differences between Coriolis and quadrature signals remain at the required 90° despite environmental variations.
Data Source
AI summary
A circuit comprising a microelectromechanical (MEMS) gyroscope and a gain circuit coupled with the MEMS gyroscope. The gain circuit is configured to receive a digitized drive signal based at least in part on a digitized drive voltage amplitude of the MEMS gyroscope. The gain circuit is also configured to determine a percentage change in quality factor of the MEMS gyroscope based at least in part on the digitized drive signal and a stored trim value of the MEMS gyroscope. The gain circuit is also configured to compensate for an effect of a change in the quality factor of the MEMS gyroscope based at least in part on the percentage change in quality factor.