A New Readout Circuit with Robust Quadrature Error Compensation for MEMS Vibratory Gyroscopes

This paper presents a front-end readout circuit for the vibratory MEMS gyroscope. The overall high dynamic range performance of the readout circuits is achieved by reducing the quadrature error signal through an additional proposed feedback path in the readout circuit. It is shown that the proposed readout can tolerate the demodulator phase error. The readout has been designed and simulated in the standard 0.18 μ m CMOS technology. Compared to the conventional structure, the simulation results show about 19 dB dynamic range improvement in the proposed closed-loop readout. The readout circuit achieves 1.7 aF capacitive resolution at 100 Hz signal bandwidth and 95.5 dB dynamic range. The deviation due to the 1-degree phase error of the demodulator is reduced by about 95 % . Moreover, the 2nd harmonic component at the output of the demodulator has been significantly reduced. The readout draws 0.6 mA from a 1.8 V supply.