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TLV320AIC3204: When the TLV320AIC3204 is powered on, the HPL and HPR will produce a PIPA sound

Luo Lu
Prodigy 230 points
Part Number: TLV320AIC3204

Tool/software:

Hello,
I am currently using IN1L and IN1R to route to HPL and HPR outputs respectively. I have encountered a problem. When I power on the TLV320AIC3204 without making any register configuration, the speakers of HPL and HPR emit PIPA noise. When we were troubleshooting this issue, we found that when the positive and negative poles of the speaker were connected to HPL and HPR respectively, the PIPA noise disappeared. However, in this case, there were no left or right channels. We need to connect the speaker to HPL and GND, and there is no PIPA noise when HPR and GND are connected. Please help solve the above questions. Thank you.
Here is our schematic diagram:

regards.

  • 0
    TI__Mastermind 46835 points

    Hi Luo,

    Do you mean there is no pop noise on HPR?

    Pop noise is caused by sudden jumps in voltage. When the codec driver is powered on, the output rises to the common mode voltage very quickly, causing the pop. Section 2.2.3.1  in the application reference guide gives good details about how the power up time of the headphone driver can be controlled to reduce pop. The advantage here is that this is all software controlled and no hardware is needed.

    An alternate solution is to use a low pass filter to slow down the transient of the pop. 

    Best regards,
    Jeff McPherson

  • 0 in reply to Jeff McPherson
    Prodigy 230 points

    Hi Jeff,

    What I mean is that there will be noise when HPL and HPR are grounded single-ended, but not when they are differential. Besides, I just powered it on and it was already making noise before I even started configuring the registers. So software control is useless. Looking at the circuit diagram, the low-pass filter is already there.

    Regards,

    Luo Lu

  • 0 in reply to Luo Lu
    TI__Mastermind 46835 points

    Hi Luo,

    It's not surprising that there is no pop noise when the speaker is connected differentially. The noise is likely being generated on both HPL and HPR and so in differential connection the pop is being cancelled out.

    Do you mean you are getting the pop sound right as power is being applied? Can you probe the outputs of HPL and HPR with respect to GND and show me what the output looks like once power is applied but no registers are set?

    Also yes the filter is there, but the resistor to GND is not populated according to the schematic.

    Thanks,
    Jeff McPherson

  • 0 in reply to Jeff McPherson
    Prodigy 230 points

    Hi Jeff,

    As shown in the figure, I changed the resistance and capacitance of the speaker, but it still emitted a pop sound when powered on. The voltage at the moment of the pop sound captured by the oscilloscope was approximately 500mV.

    The registers are still not configured.

    Regards.

  • 0 in reply to Luo Lu
    TI__Mastermind 46835 points

    Hi Luo,

    There is some additional advice in this app note regarding the power sequencing. I wonder if LDOIN being connected to reset is a problem. https://www.ti.com/lit/an/slaa492a/slaa492a.pdf?ts=1758207997893

    I also think this pop is a result of the analog LDO powering on. There is another section in the app note that recommends using a diode to keep AVDD and DVDD close together to prevent pops (Section 3).

    Best regards,
    Jeff McPherson