Electromechanical Sigma Delta Modulators \Sigma \Delta \mathrm{ M} Force Feedback Interfaces for Capacitive MEMS Inertial Sensors: A Review
Analog to digital converters based on sigma delta modulators (SAM) are a popular choice for high resolution conversion from the analog to the digital domain. With relatively small modifications, they can also be used as electromechanical SAM (EM SAM) force feedback interfaces for capacitive micro electromechanical systems (MEMSs) inertial sensors. Such interfaces are able to combine the benefits of force feedback and analog to digital conversion at relatively modest circuit cost. This paper provides a comprehensive review of EM SAM interfaces for capacitive MEMS inertial sensors. The principle and the design methodology of EM SAM interfaces are introduced. A classification of EM SAM accelerometers and gyroscopes is presented, and a detailed analysis of different EM SAM architectures is given. The most representative EM SAM inertial sensors systems are discussed and compared with regard to their performance characteristics. In particular, the properties of various discrete and continuous time techniques and a system parameter optimization methodology are illustrated through specific examples. Finally, current challenges and future development trends of EM SAM interfaces for inertial sensors have been identified.
IEEE Sensors Journal