A buffer circuit for a low noise mems microphone

Abstract

The invention discloses a buffer circuit of a low-noise MEMS (Micro-Electro-Mechanical System) microphone. The buffer circuit comprises a bias module, a negative feedback module and a signal reading module; an output end of the bias module is connected with an input end of the negative feedback module; an output end of the negative feedback module is connected with an input end of the bias module;the output end of the negative feedback module is connected with an input end of the signal reading module; and an output end of the signal reading module is connected with an input end of the negative feedback module. The buffer circuit of the low-noise MEMS microphone provided by the invention can simplify a circuit structure, stabilize the quiescent current of the signal reading module, and reduce the circuit noise, so that the buffer circuit of the MEMS microphone can accurately read out voltage signals under the sound pressure effect within the sound bandwidth frequency, which is suitable for the input stage of an MEMS microphone sensor readout interface circuit.

Description

technical field [0001] The invention belongs to the technical field of electronics, and further relates to a buffer circuit of a low-noise MEMS (Micro-Electro-Mechanical System) microphone in the technical field of analog integrated circuits. The invention can be used as the input stage of the readout interface circuit of the MEMS microphone sensor, and can accurately read the voltage signal under the action of the sound pressure. Background technique [0002] MEMS microphones are widely used. In the design of the MEMS microphone readout interface circuit, the buffer circuit is a key module. This module needs to accurately read the voltage signal under the action of sound pressure. The traditional buffer circuit is usually implemented by an op amp, but the op amp has a complex structure, high power consumption and noise, high cost to deal with noise, and takes up a large chip area. In order for the buffer circuit to accurately read the signal, the buffer circuit must have l...

AI Technical Summary

Problems solved by technology

Although the circuit is easy to implement, the disadvantages of this circuit are that the power consumption is large, the noise is high, the cost of processing noise is high, and the chip area is large.

This circuit structure has the advantage of high input impedance and can read signals very well. However, the disadvantage of this readout circuit is that because the circuit uses resistors and operational amplifiers to achieve high input impedance, this method is relatively Complex, and the resistor occupies a large chip area

Images