Weak Capacitance Detection Circuit of Micro-Hemispherical Gyroscope Based on Common-Mode Feedback Fusion Modulation...

Area of Science:

• Electrical Engineering
• Sensor Technology
• Micro-electro-mechanical Systems (MEMS)

Background:

• Micro-hemisphere gyros produce capacitance signals below the picofarad (pF) level.
• Capacitance signal acquisition is challenging due to parasitic capacitance and environmental noise.
• Improving noise reduction in MEMS gyro capacitance detection circuits is crucial for enhanced performance.

Purpose of the Study:

• To propose a novel capacitance detection circuit for micro-hemisphere gyros.
• To significantly reduce noise in the capacitance signal acquisition process.
• To enhance the accuracy of detecting weak capacitance signals from MEMS gyros.

Main Methods:

• Implementation of input common-mode feedback to counteract voltage drift.
• Utilization of a low-noise, high-gain amplifier to minimize equivalent input noise.
• Integration of a modulator-demodulator and filter for effective noise mitigation.

Main Results:

• The proposed circuit achieves an output dynamic range of 102 dB with a 6 V input voltage.
• The output voltage noise is measured at 5.69 nV/√Hz.
• A high sensitivity of 12.53 V/pF was experimentally verified.

Conclusions:

• The novel capacitance detection circuit effectively reduces noise in MEMS gyro signal acquisition.
• The circuit demonstrates superior performance in terms of dynamic range, noise level, and sensitivity.
• This advancement is key to improving the accuracy and reliability of MEMS gyro-based systems.