• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 31 subscribers
  • Views 3914 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPA3255: The Idle losses are too big in the test

Robin Yu
Intellectual 2190 points
Part Number: TPA3255

According to datasheet, TPA3255 achieves both high power efficiency and very low power stage idle losses below 2.5W.

But in the test of customer, the idle losses are about 5W.

Below is the schematic, please help look at if there is something wrong? Thanks.

  • 0
    TI__Genius 9670 points

    Hi Robin,

    The setup of the device looks okay:

    • Frequency Adjust is 450kHz (lowest switching frequency)
    • Mode Pins: 2x BTL mode

    It may be something related to the output filter. 

    Could you please send the components in the LC output filter for review?  Core losses in the inductors or output components can have huge effects on power performance.

    Thanks,
    Brian

  • 0 in reply to Brian Burk
    TI__Intellectual 2190 points

    Hi Brian,

    Please see the part number of LC.

    Could you get the related information what you want?

    Thanks.

    DLM1623C-100M-R

    L509，L510

    CL23BII-100V-105JR, C242A105J2SA201

    C600, C606, C612, C626,

    Robin

  • 0 in reply to Robin Yu
    TI__Mastermind 27990 points

    Hi Robin,

    The schematic does not have anything that jumps out as wrong, or that would cause higher idle loss. As Brian mentioned just a change in inductors can have a major impact on idle loss depending on the properties of the inductor. We have not tested that specific inductor before, but we do have idle numbers for other inductors. I have attached our spread sheet of inductor tests.

    Are there any other issues with this board? Does the output meet the performance numbers besides idle loss?

    I would recommend you perform the following tests: 

    • Get a known inductor, like the toroid on the EVM, or one from our tests and measure the idle loss on the new board. This should show you if you roughly get the same idle loss as our tests, or it is way off, meaning something else in the circuit is wrong.
    • Use the DLM1623C-100M-R inductor on our EVM and see if the idle loss matched the new board.

    These tests should show if the inductor is the main reason for the higher idle loss, as the default EVM gets about 1.5W of idle loss with the toroid inductors.

    JustinTPA3255 inductor comparison .xlsx

  • 0 in reply to Justin Bohr
    TI__Intellectual 2190 points
    Hi Justin,

    Thanks, I will deliver it to customer.
    Once I get the feedback, I will come back to you.
    Thanks again.

    Robin