EVAL-ADAU1761Z - interfacing with an electret microphone - CCPL input needed
Hello,
For my project (active noise control in an experimental rocket), I'm planning to use this microphone : http://www.bksv.fr/doc/bp2055.pdf
It needs a CCPL supply (2 to 20mA, 24 to 30V) to work.
My question is : is there a way to use the microphone bias available with differential inputs to interface this microphone ? I read in the datasheet that the bias current source is 3mA which is ok, but bias voltage is only 2,97V max, which is not enough...
Anyway the output of the microphone is not compliant with the 0,5V RMS differential input, so I have to find a way to interface it correctly (gain, offset, ...). Could you help me with that, since there would be some useful ADI hardware to do that ?
Thank you very much,
Lucas
Audio Signal Processors
microphone
ccpl
SigmaDSP Audio Processors
adau1761
bias
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Hi Lucas,
You would need to supply the bias voltage to the mic from an external source. The differentail mic output could be AC coupled to interface with the ADAU1761, however it sounds like you would also need to gain down the signal to fit in the ADC range. This could be done by adding series resistors in the input path that will create a resistor divider with the input resistance of the ADAU1761.Hope this helps.
Best Rgds,
Alan
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