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TPA3132D2: inductor is hot without speaker

[FAE] Andrew Wang
Genius 10685 points
Part Number: TPA3132D2


Hi Team,

Quick question regarding my customer's design, they reported TPA3132D2 on their board is consuming 24V/160mA, so the inductor is hot. 

The heat stays, no matter with or without the speaker.

Customer would like to confirm if this is normal or not?

My personal question is that, TPA3132 uses AD modulation? therefore it has continuous common mode current through the inductor which cause the heat?

SCH is attached below, thanks for teaching!

Andrew

  • 0
    TI__Mastermind 24835 points
    Hi Andrew,
    TPA3132D2 use BD modulation mode, so the common mode output filter should work for it. For output filter design, please find more info in this document: www.ti.com/.../slaa701a.pdf
    May I know how much is the temperature on the board/inductors? The idle current on the TPA3132D2 EVM with PVCC=24V is less than 70mA and the temperature should be very low. I can't see the whole SCH, please compare your design with our TPA3132D2 EVM: www.ti.com/.../slou375.pdf Please try to decrease the PVCC(e.g. 12V) to see if the issue is still there. If yes, need to make sure the soldering is good, including device and components on the board. If no, please try to use the inductors with higher saturation current.
    Best regards,
    Shawn Zheng
  • 0 in reply to Shawn Zheng
    TI__Genius 10685 points
    Hi Shawn,

    Thanks for feedback.
    I confirmed there are two TPA3132D2 on the board and altogether consuming ~160mA, so seems current consumption are fine.
    Customer checked 6 inductors with thermometer，there are 4 of them over 80C, no speaker, no load, at room temp.
    But with 12V PVDD, the inductor temp will drop to 30~50C range.
    That sound ok for you?
    The rating for inductor used on the board are 2.5A.
    Any idea what might be wrong with their circuit?
    Thanks!

    Andrew
  • 0 in reply to [FAE] Andrew Wang
    TI__Mastermind 24835 points
    Hi Andrew,
    The idle current looks fine for two AMP's. But I'm curious that where the heat is from because the current consumption is very low. Did you try to remove the subbers on the output(only reserve the 10uH inductors and 1uF caps) to see if the issue is still there? Please also try to use the other inductors(we use 931BS-100M on the EVM). Make sure the soldering is good on the board.
    Best regards,
    Shawn Zheng