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Pop noise, TPS65950A3, Pre.driv

Mahesh Hooli
Intellectual 740 points
Other Parts Discussed in Thread: TPA2010D1, TPS65950

Hi All,

We are seeing a pop noise whenever audio is enabled. We have connected Predriv Left of TPS65950 to 8ohm speaker through Class D TPA2010D1.

When we measured the Predriv.left signal, we could see that there is a DC content for ~90mSec before actual audio comes out. Is something wrong with the register configuration sequence?

Thank you in advance for the reply.

Thanks and regards,

Mahesh Hooli

  • 0
    Intellectual 740 points

    Hi,

    To debug the above Pop noise issue, we isolated the Predriv_L from Class D amplifier input and probed the Predriv_L line.

    By default the Predriv_L line is low (0V). Whenever I execute command amixer cset name='PreDriv Playback Volume' 3,3, It rises to 1V very sharply and comes down.

    If I disable it by running amixer cset name='PreDriv Playback Volume' 0,3, the Predriv_L line goes to -1V sharply before it comes back to 0V.

    Please find the oscilloscope captures below ( when Predriv is enabled or disabled).

    Do we have to follow any particular sequence in configuring the PMIC registers to avoid this pop up?

    Thanks and regards,

    Mahesh Hooli