An Interface ASIC for MEMS Vibratory Gyroscopes with Nonlinear Driving Control.

Area of Science:

• Electrical Engineering
• Mechanical Engineering
• Sensor Technology

Background:

• Micro-electromechanical systems (MEMS) vibratory gyroscopes require sophisticated interface electronics for accurate angular velocity measurement.
• Existing interface circuits often face challenges with amplitude stabilization, linearity, and non-ideality suppression.

Purpose of the Study:

• To propose and validate a novel application-specific integrated circuit (ASIC) for MEMS vibratory gyroscopes.
• To improve the performance metrics of MEMS gyroscopes, including bias instability and nonlinearity.
• To enable seamless integration with digital systems through an on-chip analog-to-digital converter (ADC).

Main Methods:

• Implementation of a closed self-excited drive loop with peak detection and a proportion-integration (PI) controller for automatic amplitude stabilization.
• Design of a nonlinear multiplier for enhanced resonance oscillation and linearity.
• Utilizing a differential charge amplifier for capacitance variation detection and phase demodulation for signal processing.
• Incorporation of on-chip temperature drift calibration and a sigma-delta (ΣΔ) analog-to-digital converter (ADC) for digital output.

Main Results:

• The developed interface ASIC, manufactured in 0.35 μm CMOS technology, occupies a small active area of 3.2 mm².
• Experimental results demonstrate a low bias instability of 2.2 °/h.
• Achieved nonlinearity of 0.016% over the full-scale range, indicating high linearity.

Conclusions:

• The proposed ASIC effectively addresses key challenges in MEMS vibratory gyroscope interface design.
• The integrated solution offers superior performance in terms of stability and linearity.
• This work paves the way for more compact and accurate inertial sensing systems.