A High-Precision Bandgap Reference with Chopper Stabilization and V-Curve Compensation Technique

Area of Science:

• Electrical Engineering
• Sensor Technology
• Analog Circuit Design

Background:

• MEMS sensors generate weak, low-frequency signals requiring high-precision interface circuits.
• Traditional amplifiers introduce noise and offset, degrading bandgap reference accuracy.
• Stringent requirements for noise, offset, and temperature coefficient in MEMS interface circuits.

Purpose of the Study:

• To propose a high-precision, low-noise bandgap reference for MEMS sensor interface circuits.
• To improve the accuracy and reliability of MEMS sensor signal conditioning.
• To address the limitations of traditional amplifiers in low-frequency, low-noise applications.

Main Methods:

• Implemented a novel operational amplifier utilizing chopper-stabilization to minimize offset and low-frequency noise.
• Employed a V-curve compensation circuit for second-order curvature compensation.
• Designed and fabricated the circuit using a 0.18 μm CMOS process.

Main Results:

• Achieved a low temperature coefficient of 2.31 ppm/°C over -40-140 °C.
• Measured output voltage noise of 616 nV/sqrt(Hz)@1 Hz.
• Obtained a power-supply rejection ratio of 73 dB@10 kHz and linear adjustment rate of 0.33 mV/V.

Conclusions:

• The proposed bandgap reference meets the rigorous demands of MEMS sensor interface circuits.
• The circuit demonstrates excellent performance in terms of noise, temperature stability, and power efficiency.
• The design offers a viable solution for enhancing MEMS sensor accuracy and performance.