A new type of high precision mems accelerometer

Abstract

The invention relates to an accelerometer, in particular to an MEMS accelerometer. Specifically, a high speed digital quantization unit is embedded in a sigma-delta full closed-loop circuit of the MEMS accelerometer, and through signal estimation and processing, an MEMS full closed-loop sigma-delta system consisting of a low bit quantizer can achieve full digital closed-loop and high bit digital quantization output. Through a signal processing algorithm and the system stability design, the invention achieves digital feedback while achieving feedback electrostatic force quantization. Meanwhile, a loop filter is realized in a digital manner, an integral windup phenomenon generated by an analog loop filter can be avoided, the layout design difficulty and the influence of noises force the analog loop filter on the system are also reduced, and Tehran performance of the MEMS accelerometer is effectively improved.

Description

technical field [0001] The invention relates to a capacitive inertial sensor, in particular to a MEMS (Micro Electro Mechanical System) speedometer digital servo circuit. Background technique [0002] Capacitive inertial sensors generally include inertial sensors such as acceleration sensors and gyroscopes. These inertial sensors measure the acceleration of the carrier relative to the ground and other parameters in real time to determine the position of the carrier and the parameters of the earth's gravity field, and the measured changes translates into a change in capacitance. [0003] The following is an example of a MEMS (Micro Electro Mechanical System) capacitive inertial sensor. [0004] With the increasing maturity of MEMS (Micro Electro Mechanical System) technology, MEMS capacitive inertial sensors are widely used due to their small size, high sensitivity, stable DC characteristics, small drift, low power consumption, and small temperature coefficient. However, MEM...

AI Technical Summary

Problems solved by technology

However, due to the complexity and particularity of the MEMS manufacturing process, the accuracy of the parameters of the MEMS capacitive inertial sensor is poor, and the dispersion is large, which often leads to the mismatch of the originally matched loop filter, and the light one leads to the digital closed-loop servo The performance of the circuit is degraded, and in serious cases, the digital closed-loop servo circuit is unstable and cannot work normally; the loop filter realized by the analog circuit is due to the error of integrated circuit processing and the existence of parasitic effects, resulting in poor parameter accuracy of the loop filter , it is difficult to accurately control

[0009] In addition, the digital processing and compensation of signals cannot be realized by adopting the all-analog scheme, and the influence of external interference signals, such as noise and temperature, cannot be dealt with.

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