Abstract
High-Q sensing element is desirable for high performance while makes the loop control a great challenge. This paper presents a closed-loop system for high-Q capacitive MEMS accelerometer which has achieved loop control effectively. The proportional-derivative(PD)control is developed in the system to improve the system stability. In addition, pulse width modulation (PWM) electrostatic force feedback is designed in the loop to overcome the nonlinearity. Furthermore, a sigma-delta (ΣΔ) modulator with noise shaping is built to realize digital output. System model is built in Matlab/Simulink. The simulation results indicate that equivalent Q value is reduced to 1.5 to ensure stability and responsiveness of the system. The effective number of bits of system output is 14.7 bits. The system nonlinearity is less than 5‰. The equivalent linear model including main noise factors is built, and then a complete theory of noise and linearity analysis is established to contribute to common MEMS accelerometer research.
Highlights
The capacitive microaccelerometer with high measurement precision, stable output, low temperature drift, is one of the most widely used MEMS sensors
Traditional MEMS accelerometer system research is concentrated in open-loop with analog output[1]
We study a digital closed-loop system for high-Q MEMS accelerometer sensor which combines PD controller with Σ∆ modulator
Summary
The capacitive microaccelerometer with high measurement precision, stable output, low temperature drift, is one of the most widely used MEMS sensors. Closed-loop with analog output makes quality block movement near the equilibrium position improving the linearity[5]. It is affected by the precision and noise of circuit it is not conducive to the subsequent signal processing because of analog output. Another high-order Σ∆ loop system realizes low power consumption, low circuit complexity and digital output. We study a digital closed-loop system for high-Q MEMS accelerometer sensor which combines PD controller with Σ∆ modulator.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
