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TPA3124D2 Class D Power Amp Output Clicking

Other Parts Discussed in Thread: TPA3124D2, TPA3123D2EVM

Can anyone help me with this. I am using a TPA3124D2 for audio power amp and I am using all the recommended values mentioned in the datasheet and the evaluation board (tpa3124d2evm) but when my input is lower than a certain limit or goes to ground the output starts "click"ing. I cant figure out why this happens. I have an eval board and this does not happen on the eval board. And as I said before all the component values are the same as eval board.

Any help would be appreciated.

  • Hi, Ali,

    It happens when your input level is "lower?" Really?

    I suspect an issue with your output filter. If the output filter components aren't correct, it causes a resonance in the output filter which will trip the short-circuit protection.

    For more on output filter design, please read this app note.

    If this solves your issue, please click "Verify Answer!" Thanks!

    -d2

  • Hi Don,

    Thanks for your response. I suspected my output filter as well. To test it I exchanged the filter inductor and capacitor of my board with the eval board. But the result was the same. My board still doesn't work with the filter from the eval board. and the eval board still works flawlessly with my filter components. So that might not be the problem.

    As I said before I am using the recommended values by TI. The only difference on my board is the layout because I had to put all the components on the TOP side so I have layed out the tracks differently from the eval board. Would that cause any problem of this sort?

    and the app note is very informative, thanks but as I said does not solve my problem.

    Regards, 

  • Hi, Ali,

    I suspect it is due to your PCB's layout. Voltage transients can trip the Short-Circuit Protection on the IC.

    If you would like to share your layout, we can review it.

    -d2

  • Hi Don,

    Here is my PCB layout. It is in altium format. The audio enters on P10 and the speaker connects to P11. I have put parts on the board to be able to have it both as BTL or SE Output. Power is +24V on P14. Really appreciate your help on this.

    Regards,

    4377.PowerAmpSection.zip

  • Hi, Ali,

    Sorry, I have not had time to review your layout.

    Did you get the issue resolved yet?

    -d2

  • Hi Don,

    No the issue is still there. but looks like GND noise. I'm working on a new layout.

    By any chance is it possible to get the gerbers or layout files of the eval board? I couldn't find it in the downloads section.

    Thanks,

  • Hi, Ali,

    Sorry about that! We have posted the gerbers in the TPA3123D2EVM Product Folder, and the PCB is the same between the two ICs.

    You can find the files here: http://www.ti.com/tool/tpa3123d2evm

    -d2