Study of closed-loop high-resolution sigma-delta for a MEMS accelerometer

IEICE Electronics Express

Zhiyuan Sun¹  Liang Yin²  Xiaowei Liu²  Xiangyu Li²  Qiang Fu² 

[1] Key Laboratory of Earthquake Engineering and Engineering Vibration, Institute of Engineering Mechanics;MEMS center, Key Laboratory of Micro-Systems and Micro-Structures Manufacturing

关键词: MEMS accelerometer;    interface circuit;    capacitance compensation array;    Sigma-Delta;   

DOI  :  10.1587/elex.14.20171090

学科分类：电子、光学、磁材料

来源: Denshi Jouhou Tsuushin Gakkai

【 摘 要 】

In this paper, a high-resolution Sigma-Delta (ΣΔ) modulator in a standard 0.5 µm CMOS technology for a MEMS accelerometer is presented. The digital output is attained by the interface circuit based on a low-noise front-end charge-amplifier and a back-end forth-order Sigma-Delta modulator. The low-noise front-end detection circuit is proposed with correlated double sampling (CDS) technique to eliminate the 1/f noise and offset of operational amplifier. The capacitance compensation array is used for rejecting the sensor element mechanical offset. The lead compensator circuit is to ensure the stability of the high-order closed-loop system. The interface is fabricated in a standard 0.5 µm CMOS process and the active circuit area is about 8 mm2. The MEMS accelerometer system consumes 25 mW from a single 7 V supply at a sampling frequency of 250 kHz. The ΣΔ modulator can achieve an effective number of bits 20.30 bits and an average noise floor in low-frequency range of 140 dB.

【 授权许可】

CC BY