A Digital Closed-Loop Sense MEMS Disk Resonator Gyroscope Circuit Design Based on Integrated Analog Front-end

Area of Science:

• * Engineering and Applied Physics
• * Microelectromechanical Systems (MEMS)

Background:

• * Microelectromechanical systems (MEMS) disk resonator gyroscopes (DRGs) are crucial for inertial navigation.
• * Existing DRG systems face challenges with non-ideal factors and digital integration.

Purpose of the Study:

• * To propose and validate a digital closed-loop system design for a MEMS DRG.
• * To enhance DRG performance by addressing vibration models and control loops.

Main Methods:

• * Developed vibration models incorporating non-ideal factors for the MEMS DRG sensing element.
• * Implemented a force balance mode with four control loops, including a self-excited loop for amplitude stabilization and a force-to-rebalance loop.
• * Utilized a high-frequency carrier on the anchor to mitigate parasitic capacitance coupling and a sigma-delta (ΣΔ) analog-to-digital converter (ADC) for digital signal processing.

Main Results:

• * Achieved a bias instability of 2.1 °/h and nonlinearity of 0.035% over a ± 400°/s full-scale range.
• * The implemented sigma-delta (ΣΔ) analog-to-digital converter (ADC) demonstrated a 111.8 dB signal-to-noise ratio (SNR).
• * The analog front-end and digital control loop were successfully fabricated using standard 0.35 µm complementary metal-oxide-semiconductor (CMOS) technology.

Conclusions:

• * The proposed digital closed-loop system design significantly improves the performance of MEMS DRGs.
• * The system demonstrates high precision and stability, suitable for advanced inertial sensing applications.