Calibrated microelectromechanical microphone
AssigneeSonion A/S
InventorsJens Kristian Poulsen, Carsten Fallesen, Lars Jorn Stenberg, Jozef Johannes Gerardus Bosch
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Abstract
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.
Claims12
A MEMS microphone assembly including a microphone housing, the MEMS microphone assembly comprising:
- a sound inlet;
- a MEMS transducer element having a back plate and a diaphragm displaceable in relation to the back plate;
- a controllable bias voltage generator adapted to provide a DC bias voltage between the diaphragm and the back plate;
- a memory for storing information including amplifier gain setting information;
- a controllable amplifier for receiving an electrical signal from the MEMS transducer element and providing an output signal, the controllable amplifier being adapted to amplify the electrical signal from the MEMS transducer in accordance with an amplifier gain setting;
- and
- a processor adapted to retrieve information from the memory and to
- control the gain of the amplifier in accordance with the amplifier gain setting information from the memory, and
- control the bias voltage generator to provide a DC bias voltage in accordance with the information from the memory.
A method of calibrating a MEMS microphone assembly comprising a MEMS transducer element, the method comprising the steps of:
- measuring or estimating a collapse voltage of the MEMS transducer element;
- determining a DC bias voltage for the MEMS transducer element on the basis of the measured or estimated collapse voltage;
- and
- writing information relating to the determined DC bias voltage to a memory of the microphone assembly.
Dependencies are inferred from the claim text.