PROJECT TITLE :

Design and Implementation of a MASH2-0 Electromechanical Sigma–Delta Modulator for Capacitive MEMS Sensors Using Dual Quantization Method

ABSTRACT:

In this paper, a new management structure based on the dual quantization technique is presented for an electromechanical sigma-delta modulator (EM-ΣΔM) applied to a microelectromechanical system (MEMS) accelerometer. The modulator adopts a a pair of-zero multistage noise shaping structure (MASH2-zero), taking the advantage of the intrinsic linearity of single-bit quantization and also the reduced quantization error of multibit quantization in an exceedingly single modulator. The sensor system is studied by the system-level modeling and the hardware implementation based on the sector-programmable gate array technology. The study shows that, MASH2-zero shares the benefits of a MASH2-a pair of architecture of having an inherent stability, a high overload input level, and a high dynamic range compared with single-loop EM-ΣΔM. However, the MASH2-0 architecture edges from a considerably simpler implementation, whereas achieving a better dynamic vary and a higher signal-to-noise ratio compared with a MASH2-a pair of and a fourth-order single-loop ΣΔM architecture. A capacitive MEMS accelerometer was designed and employed with this control system. At intervals a bandwidth of one kHz, the sensor achieved a noise floor level of -a hundred thirty dB and a bias instability as low as twenty μg at an integration time of 40 s. Simulation estimated a full scale of ±20 g acceleration. The investigation confirms the concept of the MASH2-zero structure and shows its potential as a closed-loop interface for high-performance capacitive MEMS accelerometers.