Programmable closed loop Sigma-Delta micro accelerometer and control system

Abstract

The invention relates to the field of control circuits, in particular to a programmable closed-loop Sigma-Delta micro-accelerometer and a control system. The programmable closed-loop Sigma-Delta micro-accelerometer control system provided by the present invention forms a closed-loop loop by connecting the micro-acceleration sensor, the front-end detection circuit, the AD conversion circuit, the FPGA signal processing circuit and the control circuit end to end, and the sigma-delta modulation technology When applied to the control system, the signal-to-noise ratio and accuracy of the closed-loop micro-accelerometer are improved. At the same time, the control circuit composed of the sigma-delta modulator implemented by FPGA and DSP can be modified or redesigned at any time, which improves the flexibility of the entire system. The sigma-delta modulation technology is applied to the micro-accelerometer, which reduces the noise floor of the closed-loop micro-acceleration system and improves the signal-to-noise ratio. At the same time, it adopts a digital circuit processing method to reduce the error caused by the analog device, and can achieve high precision output.

Description

technical field [0001] The invention relates to the field of control circuits, in particular to a programmable closed-loop Sigma-Delta micro accelerometer and a control system. Background technique [0002] Micromachined accelerometer is an important inertial sensor widely used in automobiles, missiles and other fields. When there is acceleration in the outside world, the closed-loop control method introduces electrostatic force. Under the action of electrostatic force, the sensitive mass is always kept near the center position, which reduces the nonlinearity of the system and improves the stability of the system. At the same time, the use of digital pulse width feedback instead of analog feedback is conducive to improving the linearity of the electrostatic force and avoiding mutual adsorption between the mass block and the detection electrode due to excessive electrostatic force. Compared with the traditional analog-to-digital converter, the Sigma-Delta modulator can achie...

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Problems solved by technology

[0003] The purpose of the present invention is to overcome the problem that the Sigma-Delta micro-accelerometer based on the analog circuit in the prior art is greatly affected by the adaptation error of the analog device, and the same circuit cannot be adapted to different occasions, thereby causing a long development cycle, and provides a digital programmable Sigma-Delta modulator to improve the signal-to-noise ratio of the system, realize digital output, and use DSP to realize the back-end control circuit

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