A calibrated microelectromechanical microphone

Abstract

The invention relates to a calibrated microelectromechanical microphone. A MEMS microphone comprising a MEMS transducer having a back plate and a diaphragm as well as controllable bias voltage generator providing a DC bias voltage between the back plate and the diaphragm. The microphone also has an amplifier with a controllable gain, and a memory for storing information for determining a bias voltage to be provided by the bias voltage generator and the gain of the amplifier.

Description

technical field [0001] The present invention relates to calibrating microphones and in particular to microcomputer-based telephone microphones comprising a memory with calibration data for setting the electrical parameters of the microphone. Background technique [0002] During normal operation, microelectromechanical ("MEMS") microphones are typically provided with a fixed DC bias between the diaphragm and the chassis structure. In EP 1599607A2 a specific operation of a DC bias for removing or reducing the electrostatic attraction between the diaphragm and the chassis is proposed and disclosed under microphone default conditions in combination with so-called diaphragm collapse. [0003] US 2006 / 062406 A1 discloses a condenser microphone comprising a programmable DC bias for the microphone's condenser transducer and a memory for storing the DC bias setting. WO 01 / 78446A1 discloses an electret microphone comprising a variable sensitivity / variable gain circuit connected betwe...

AI Technical Summary

Problems solved by technology

However, there is some impact on performance parameters such as amplifier gain and impedance

This effect is difficult to remove in loud, low-cost MEMS microphones where low-complexity amplifier topologies are critical to keep die-area costs low

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