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TAS6584-Q1: Audio clipping issue

Puneet Sahu
Prodigy 110 points
Part Number: TAS6584-Q1


Hi,
I am working on Amplifier TAS6584-Q1 chip. where I am geeting Audio clipping issue after increasing of volume.(7 volume step out of 45).

To fix this issue can you suggest some sollution or point of debug ?

From internal team I got suggestion to use  PVDD register but it looks like it is read only register. Can I change/write it ? if yes what value should it use?

Thanks & Regards,
Puneet sahu

  • 0
    TI__Guru 51840 points

    Hi 

    If TAS6584's output is larger than your PVDD, it will clipping.

    What is the PVDD voltage in your system?

    And after you increase the volume, what is the output voltage?

  • 0
    Prodigy 110 points

    Hi,

    I have tested the issue at multiple voltage levels for our ICM(Volvo) project

    At 24 volt input power supply.

    PDVV register value is 23.75 V as shown in attached screen short.
    Output voltage is shoring 16.50 Vrms
    Clipping is still present is at the full volume as shown in attached Screen short

    Speakerout Vrms

    RegisterPrints

    ClippingWave.




  • 0 in reply to Puneet Sahu
    TI__Guru 51840 points

    Hi 

    For 24V power supply, you can't give too large volume, as the device will try to output 43V peak output for max input, will definitely clipping.

    Have a try to set Analog Gain in register 0x4A to 0x4D. Use the value 0x16.

  • 0 in reply to Shadow He
    Prodigy 110 points
    Shadow He said:
    For 24V power supply, you can't give too large volume, as the device will try to output 43V peak output for max input, will definitely clipping.

    Hi, As per the product requirement we have to use 24Volt common power supply.
    I have Tested with 15 volt power supply for debugging propose but still clipping is present.
      

    Shadow He said:
    Have a try to set Analog Gain in register 0x4A to 0x4D. Use the value 0x16.

    I have tested as per your input by setting Analog gain register 0x4A to 0x4D value provided 0x16 but the clipping was still there.
    Clipping Screen Short attached for reference :-



    What is the maximum channel out put for 24 Volt input supply ?
    if possible can you suggest some more change to test it.? 

    Note:- It is high priority issue tracking from customer side which need to provide the immediate fix.

    Could we connect on a call to sort out this issue?

  • 0 in reply to Puneet Sahu
    TI__Guru 51840 points

    Hi

    Puneet Sahu said:
    I have Tested with 15 volt power supply for debugging propose but still clipping is present.

    Please use 24V to test, otherwise you need to further reduce volume, or Gain.

    Puneet Sahu said:
    What is the maximum channel out put for 24 Volt input supply ?

    The max is just 24V peak sinewave. 

  • 0 in reply to Shadow He
    Prodigy 110 points

    Hi,

    I’ve set the Analog Gain for all four channels to 0x16, as suggested. However, this change does not seem to make any noticeable difference at full volume.

    Could you please confirm if there are additional registers that need to be configured or modified to achieve the desired effect?

    Also, considering the urgency (the customer has marked the ticket as highest severity and is requesting updates three times a day), would it be possible to sync over a quick call to help narrow down the issue more efficiently?

    Thanks & Regards,
    Puneet Sahu

  • 0 in reply to Puneet Sahu
    TI__Guru 51840 points

    Hi

    Puneet Sahu said:
    Could you please confirm if there are additional registers that need to be configured or modified to achieve the desired effect?

    Could you tell me what is your desired effect?

    Before developing the circuit, you should according to your PVDD voltage, target max output power, to calculate the max input level, also the Gain of amplifier need to use. Do you have all these number right now?

    The IC simply amplify your input with the Gain you set in the register. If such kind of clipping happens, it's either you raise your PVDD voltage, or decrease the input signal, or decrease the Gain settings. They should be calculated.

    Use oscilloscope to capture the waveform, capture the PVDD voltage also the Output at the same time. Observe the waveform, and do the changes that I just mentioned, to find the relationship with all these parameter.