オンチップの中和キャパシタ及び線形作動を用いて自動キャリブレーションを行うことによる容量性変換器の線形性増大

摘要

A system and method are disclosed for automatically calibrating capacitive transducers to neutralize feed-through capacitance using linear actuation. The method includes starting with an initial neutralization capacitance, applying no electrostatic force and two known electrostatic forces to a proof mass of the transducer, recording the transducer output changes due to the applied forces; and determining how to revise neutralization capacitance based on the changes. The method can use a binary search to find a final neutralization capacitance providing the best linearity. The method can include comparing the final linearity to a threshold linearity. The electrostatic forces can be applied using a charge control method where the electrostatic force is a linear function of the actuation duration. The linear actuation can be used for continuous self-test of capacitive sensors.