MEMS accelerometer reading circuit

Abstract

The invention provides an MEMS accelerometer reading circuit which comprises an output module. The output module is an output conversion module including differential output and single-end output, and the output conversion module is of a two-end differential type signal detection and processing structure. A capacitance bridge is built outside, can be applicable to various accelerometer headers and solves the direct-current deviation problem. Circuit precision is high, and the resolution ratio of output signals is high.

Description

technical field [0001] The invention relates to the field of MEMS micro-inertial instruments, in particular to a MEMS accelerometer readout circuit. Background technique [0002] The structure of the MEMS capacitive micro accelerometer is small, the output signal is very weak, and it is an analog signal, and the capacitance change is very small, generally within 10 -15 F is about F, and it is seriously affected by parasitic capacitance and various noises. It is very difficult to detect this output signal and convert this signal into an electrical signal. Moreover, MEMS accelerometers change greatly with the integration process, and the device parameters have high uncertainty and various nonlinearities; the weak signal detection problem of its output has always been a prominent problem that plagues researchers. [0003] The existing MEMS accelerometer readout circuit structure has two kinds of single-ended detection structure and differential detection structure. [0004] S...

AI Technical Summary

Problems solved by technology

[0002] The structure of the MEMS capacitive micro accelerometer is small, the output signal is very weak, and it is an analog signal, and the capacitance change is very small, generally within 10 -15 It is around F, and it is seriously affected by parasitic capacitance and various noises. It is very difficult to test this output signal and convert this signal into an electrical signal.

Moreover, MEMS accelerometers change greatly with the integration process, and the device parameters have high uncertainty and various nonlinearities; the weak signal detection problem of its output has always been a prominent problem that plagues researchers.

However, the output signal of this structure is a single-ended output, and there will be a large uncertain DC offset problem. In addition, this structure only has an open-loop working mode.

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