Capacitance reading circuit of inertia detecting element

Abstract

The invention provides a capacitance reading circuit of an inertia detecting element. The capacitance reading circuit is characterized in that the input end of a pre-amplifier is connected with the signal output end of the inertia detecting element, and the output end of the pre-amplifier is connected with a first sampling holder and a second sampling holder. The pre-amplifier is used for pre-amplifying output signals of the inertia detecting element, and then outputs the signals to the first sampling holder and the second sampling holder. The output end of the first sampling holder is connected with the first input end of a differential amplifier, and the output end of the second sampling holder is connected with the second input end of the differential amplifier. The first sampling holder transmits the output signals of the inertia detecting element to the first input end of the differential amplifier, and the second sampling holder transmits the output signals of the inertia detecting element to the second input end of the differential amplifier. The output voltage of the differential amplifier is a voltage signal of the inertia detecting element. The output voltage of the capacitance reading circuit and displacement of a mass block are in linear relation, and an electrical spring effect does not exist.

Description

technical field [0001] The invention relates to the technical field of inertial detection, in particular to a capacitance readout circuit of an inertial detection element. Background technique [0002] Inertial detection components generally include inertial sensitive components such as acceleration sensors and gyroscopes. These inertial detection components measure the acceleration of the vehicle relative to the ground and other parameters in real time to determine the position of the vehicle and the parameters of the earth's gravity field. [0003] The MEMS (Micro Electro Mechanical System) acceleration sensor is taken as an example to introduce below. [0004] The MEMS acceleration sensor is an inertial detection element formed on a silicon wafer through a micromachining process. The mechanical structure of a typical MEMS acceleration sensor is a mass block-spring structure. Such as figure 1 As shown, the proof mass 200 is suspended in the frame 100 of the inertial det...

AI Technical Summary

Problems solved by technology

[0055] It can be seen from Table 1 that the electric spring effect generated by the driving voltage affects the measurement results. Reducing the driving voltage will reduce the influence of the electric spring effect on the measurement, but at the same time it will reduce the signal-to-noise ratio of the measurement circuit

[0056] To sum up, the output voltage of the differential capacitance readout circuit in the prior art has a nonlinear relationship with the displacement of the mass block, and there is an electric spring effect

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