High-Power-Efficiency Readout Circuit Employing Average Capacitance-to-Voltage Converter for Micro-Electro-Mechanical...

Area of Science:

• Electrical Engineering
• Sensor Technology
• Microelectronics

Background:

• Traditional micro-electro-mechanical system (MEMS) accelerometer readout circuits face power consumption challenges due to high sampling frequency requirements.
• Parasitic capacitance in MEMS sensors necessitates high sampling rates in capacitance-to-voltage converters (CVCs) and analog-to-digital converters (ADCs), increasing power draw.
• Noise aliasing and deterioration are significant issues in conventional CVC-based systems.

Purpose of the Study:

• To propose and evaluate an average capacitance-to-voltage converter (CVC) technique for enhancing power efficiency in MEMS accelerometer readout circuits.
• To mitigate the high sampling frequency demands on analog-to-digital converters (ADCs) in MEMS sensor systems.
• To reduce overall power consumption without sacrificing noise performance.

Main Methods:

• Development of an average capacitance-to-voltage converter (CVC) technique.
• Simulation of both traditional and proposed readout circuits using a 0.18 μm BCD process.
• Fabrication and testing of the proposed CVC circuits in an 0.18 μm BCD process.

Main Results:

• The proposed average CVC technique eliminates noise aliasing issues present in traditional circuits.
• A 53% reduction in power consumption was achieved with the proposed readout circuit.
• Simulation demonstrated a 12 dB increase in noise power spectral density (PSD) for traditional circuits when ADC sampling frequency was reduced, an effect absent in the proposed design.
• Experimental results confirmed superior performance of the average CVC technique over traditional CVCs.

Conclusions:

• The average CVC technique offers a significant improvement in power efficiency for MEMS accelerometer readout circuits.
• This method effectively addresses noise aliasing and reduces power consumption without performance degradation.
• The proposed CVC approach is a viable solution for developing more energy-efficient MEMS sensor systems.