Low-noise MEMS capacitive sensor interface circuit

Abstract

The invention discloses a low-noise MEMS capacitive sensor interface circuit which mainly solves the problems of gain errors and circuit noise deterioration. The device comprises an MEMS mechanical sensing element, an input common-mode control circuit, a capacitance-voltage conversion module and a clock control signal generation module. The MEMS mechanical sensing element is used for converting an external acceleration signal into a variable quantity of an MEMS mechanical capacitor and generating sensor charge signals A and B; the input common-mode control circuit is used for absorbing common-mode components of sensor charge signals, and other differential-mode components are transmitted to the integrating capacitor for signal amplification, so that conversion of capacitor voltage is realized. And the gain precision is improved by introducing the sampling holding capacitor, so that the original high-gain operational amplifier can be replaced by the low-gain operational amplifier. Due to the introduction of the bandwidth compensation capacitor, the interface circuit can work under a clock with higher frequency, and the noise floor of the interface circuit is reduced. The purposes of not additionally increasing the power consumption of the circuit and reducing the noise of the interface circuit are achieved.

Description

technical field [0001] The present invention belongs to the field of integrated circuits, and more particularly relates to the processing of signals of microelectromechanical systems (MEMS) sensors. Background technique [0002] MEMS, or Micro-Electro-Mechanical System, is a multidisciplinary frontier research field developed on the basis of microelectronics technology. After more than 40 years of development, it has become one of the major scientific and technological fields that the world pays attention to. MEMS sensors are becoming more and more popular due to their small size. MEMS sensor is a new type of sensor manufactured using microelectronics and micromachining technology. Compared with traditional sensors, it has the characteristics of small size, light weight, low cost, low power consumption, high reliability, suitable for mass production, easy integration and realization of intelligence. [0003] MEMS capacitive sensors play an important role in a wide range o...

AI Technical Summary

Problems solved by technology

However, the parasitic capacitance between the MEMS sensing element and the readout circuit causes two major problems: deterioration of gain accuracy and reduction of signal-to-noise ratio

However, the realization of low-noise performance usually leads to an increase in the overall power consumption of the interface circuit. Therefore, how to achieve low-noise performance of the interface circuit without increasing power consumption is a technical problem that needs to be solved urgently.

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