A quadrature error and offset error suppression circuitry for Silicon Micro-Gyroscope

The performance of silicon micro-gyroscope (SMG) is influenced deeply by quadrature error and offset error. The reasons for inducing quadrature error and offset error are analyzed and the expressions of quadrature error and offset error are enduced. In order to eliminate the effects of the quadrature error and offset error, as well as the inherent non- linearity in the capacitance-type sensors, a closed-loop feedback control circuit with quadrature correction is designed. The opened-loop detecting circuit is also presented because the closed- loop control approach is motivated by special features of opened- loop detecting. The designed principle of frequency difference delta_f between drive mode and sense mode, as well as quality factor Q_y, is brought forward. The results of the experiment indicate that the quadrature error and offset error are corrected. By comparing with opened-loop detecting, the closed-loop feedback control circuit with quadrature correction decreases the non- linearity of scale factor from 16.02% to 0.35%, widens the maximum rate capability from plusmn270deg /s toplusmn 370deg /s and increases the stability of zero bias by 2.5 times.