Innovative control systems for MEMS inertial sensors

In this paper a variety of innovative control systems for MEMS inertial sensors are discussed. These control interfaces have considerable potential to improve important characteristics of MEMS inertial sensors, such as linearity, bandwidth, dynamic range and susceptibility again fabrication tolerances. All control systems are based on the incorporation of the micromachined sensing element in a sigma-delta modulator loop forming an electro-mechanical sigma-delta modulator (EMSDM). A very effective design methodology for such EMSDM based on a Genetic Algorithm is introduced. Subsequently, a high order, single loop EMSDM and a Multi Stage Noise Shaping (MASH) EMSDM are discussed for an accelerometer. For MEMS gyroscopes, results from a bandpass EMSDM and a novel quadrature EMSDM are presented.