Andreas Meckes

Sensitivity Enhancement of MEMS Inertial Sensors Using Negative Springs and Active Control

In this paper we present a device in which the inherent control scheme of force feedback loops in Σ/Δ-archi-tecture [1] is used for increasing the mechanical sensitivity of differential capacitive inertial sensors in combination with “negative springs”. As a consequence, the input-referred electronic noise and quantization noise is significantly reduced in the signal band. Since electronic noise can influence the loop’s stability, Σ/Δ-theory is tailored to micromechanical sense loops. Results from system simulation and measurement of an accelerometer demonstrate a significant improvement in sensitivity.