Low Noise Feed-Through Compensation Circuit Design for Resonant MEMS Pressure Sensor

Area of Science:

• Electrical Engineering
• Sensor Technology
• Measurement Science

Background:

• The feed-through effect in resonant pressure sensors causes noise, degrading performance.
• Existing sensor test systems suffer from reduced sensitivity and linearity due to this interference.

Purpose of the Study:

• To design a low-noise charge amplifier with feed-through compensation for high-precision pressure sensor measurements.
• To mitigate the detrimental effects of the feed-through phenomenon on sensor accuracy.

Main Methods:

• Developed an improved charge amplifier with a differential common-source output buffer for reduced noise and increased input impedance.
• Created a feed-through compensation circuit based on sensor equivalent circuit modeling and feed-through effect analysis.
• Conducted experimental testing to validate the circuit's effectiveness in suppressing feed-through signals.

Main Results:

• Achieved a 65% reduction in noise power spectral density (26.74 nV/√Hz) for the charge amplifier.
• Successfully eliminated a 34,919 Hz interference frequency caused by the feed-through capacitor.
• Reduced the resonance peak of the pressure sensor by 8 dBV (-40.75 dBV), improving signal clarity.

Conclusions:

• The designed circuit effectively suppresses feed-through interference in resonant pressure sensors.
• Measurement accuracy of the sensor test system is significantly improved.
• Provides a foundation for developing low-noise, high-precision, and reliable sensor test systems.