TLV320AIC3100: The Line signal input

Hayashi

Part Number: TLV320AIC3100

Hi teams,

My customer wants to connect a condenser microphone to MIC 1 RP (R channel) and connect condenser microphone or input line level signal to MIC 1 LP (L channel) .

They have a issue these circuit.

The issue is that When the big sound input to MIC1LP with a line level signal, The sound appears to be leaked even on the MIC1RP(R channel) side.

Please let me know the follow questions.

I.Would you teach me the cause, measures, etc. of such problems occurring?

II.Is there anything better to be careful when setting registers?

Best regards

Hayashi

over 7 years ago

0 Steve-Wilson over 7 years ago

TI__Mastermind 30220 points

Hayashi,

The inputs are not buffered, you could think of them as different resistive paths to the same summing amplifier. Are you needing both inputs simultaneously?

best regards,
-Steve Wilson

0 Hayashi over 7 years ago in reply to Steve-Wilson

Expert 1840 points

Steve,

Thank you for your reply.
I tell you your question.

They need both input.Their circuit microphone and line input is connected from common MICBIAS Via 2.2 kohm resistance.
Are you think about this design affect the noise?

I'm waiting for your reply.

Best regards
Hayashi

0 Steve-Wilson over 7 years ago in reply to Hayashi

TI__Mastermind 30220 points

Hayashi,

Are these Condenser mics or electret mics?

Using the mic bias for multiple mics is often done, the micbias supply is likely not a culprit for noise issues. Are they having noise issues?

best regards,
-Steve Wilson

0 Hayashi over 7 years ago in reply to Steve-Wilson

Expert 1840 points

Steve,

I understand it is no problem with the same bias.

They want to connect the condenser mic for R-ch, and the condenser mic or line input for L-ch.
Their issue is that when a loud sound is input to the left line input, the interference noise will appear on the right line.
Is there any countermeasure?

Best regards
Hayashi

0 Hayashi over 7 years ago in reply to Hayashi

Expert 1840 points

Steve,

What is the current situation?
I'm waiting for your supports.

Best regards
Hayashi

0 Steve-Wilson over 7 years ago in reply to Hayashi

TI__Mastermind 30220 points

Hayashi,

Because the inputs are not buffered, there will be crosstalk. You could try using the MIC1M input for one mic to see if there is better rejection.
however if you need the bypass paths, that might not be an option.

best regards,
-Steve Wilson

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TLV320AIC3100: The Line signal input