TPA3121 output remains 0V

Bram.Dirriwachter

I am having trouble to get a TPA3121 to start. Refer to part of my schematic below.The amplifier is connected to an Audio codec, with which succesfully generates audio signals.
However when I measure on LOUT and ROUT, both outputs remain silent (0V).
I have tried shorting R83 (connecting SD_N direct to VCC_3.3), but the issue remains.
Any help how to resolve this issue is much appreciated!

Note that initially L19, L20, C95 and C96 were not present in the design, but I patched these on my proto board. The issue remains.

Thanks, Bram.

over 10 years ago

0 Bram.Dirriwachter over 10 years ago

Prodigy 50 points

0 Ivan Salazar over 10 years ago in reply to Bram.Dirriwachter

TI__Guru** 109395 points

Hi Bram,

Is the output of the amplifier switching at 50%? or the output is completely off?
It seems that the problem could be that something is triggering protection circuit.
Have you tried to remove the output filter? (Remove everything but the BST capacitors)

Best regards,
Iván Salazar
Texas Instruments

0 Bram.Dirriwachter over 10 years ago in reply to Ivan Salazar

Prodigy 50 points

Hi Ivan,

The output is not switching, it is completely turned off.
I just tried your suggestion and removed the filters. However, both outputs remain completely off.
I am suspecting that the amplifier is defective, I will get a secondary board up-and-running and try it again.

Audio

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TPA3121 output remains 0V