Compensation Technique for Capacitive Crosstalk in Continuous-Time Electro-Mechanical Sigma-Delta Modulators

AbstractThis paper presents a readout interface for gyroscopes, where the Coriolis rate signal is converted into a bitstream using a 4th-order continuous-time electro-mechanical sigma-delta modulator. The used gyroscope has separate sense and feedback electrodes allowing full continuous-time readout. A severe drawback arises when a gyroscope with this non-collocated design is employed, since the readout is active during force-feedback. Charge feed-through, caused by parasitic capacitances of the sensor in combination with force-feedback signals, drive the charge integrator front-end into saturation. This paper presents a technique for the compensation of this capacitive crosstalk, enabling stable closed-loop readout interfaces