MEMS Demodulation Phase Calibration via External Input
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Solution Overview
Problem
Micro-electromechanical systems (MEMS) devices, such as gyroscopes, experience performance degradation due to package stress, leading to errors in demodulation phase angles, which existing technologies have not effectively addressed.
Innovation Solution
A method and system for determining phase errors caused by package stress by applying external signals to MEMS devices, processing in-phase and quadrature components, and dynamically compensating for these errors to improve performance. This involves using demodulators and processing units to calculate phase errors and adjust demodulation phases, potentially through electrostatic or magnetic forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If package stress is applied to MEMS device, then device integration is improved, but demodulation phase angle accuracy deteriorates
Solution Approach 1:
The patent applies preliminary action by performing phase calibration before normal operation. An external input signal is applied to the MEMS device, and the system measures the phase response to determine calibration values that compensate for package stress effects. This preliminary calibration ensures accurate demodulation phase angles during subsequent operational use.
Solution Approach 2:
The patent uses an external input signal as an intermediary to indirectly measure and characterize package stress effects. By applying a known external signal and measuring the phase response, the system can determine calibration values without directly measuring the package stress itself. This intermediary approach allows accurate compensation while maintaining device integration.
2Measurement precision
If external input signal is applied for calibration, then phase error determination is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by using the same MEMS device structure for both normal sensing operation and calibration measurements. The external input signal calibration procedure leverages the existing demodulation and signal processing circuitry, making the calibration function integrated into the normal device operation without requiring separate dedicated calibration hardware.
Solution Approach 2:
The system performs self-calibration by using its own signal processing resources to measure and compensate for phase errors. The calibration process utilizes the device's existing demodulators and signal paths to determine calibration values, allowing the device to calibrate itself without external intervention or additional complex calibration equipment.
Data Source
AI summary
A MEMS device may output a signal during operation that may include an in-phase component and a quadrature component. An external signal having a phase that corresponds to the quadrature component may be applied to the MEMS device, such that the MEMS device outputs a signal having a modified in-phase component and a modified quadrature component. A phase error for the MEMS device may be determined based on the modified in-phase component and the modified quadrature component.