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TPS92515: For some noise on open LED

Lee, Sam
Expert 4965 points
Part Number: TPS92515

Hi team,

A cusotmer is observing some noises(?) on open LED status while using TPS92515, and it's same as TPS92515 EVM. This might cause an issue in each PCB functional check after SMT process. Is there any way to prevent the noise output?

Thanks,

Sam Lee

  • 0
    TI__Mastermind 28655 points
    Hello Sam,

    I'm not sure what you are asking? If the LED string is open it cannot regulate current. It will also cycle through the boot capacitor refresh cycle since the inductor cannot pull the switch node to recharge the boot capacitor.

    What do you mean by noise? There cannot be LED current if the LED string is open?
    You cannot functional test the board without a load, it won't work that way.

    Regards,
  • 0 in reply to Irwin Nederbragt
    TI__Expert 4965 points
    Hi Irwin,

    Thank you for your reply. I'm sorry for not giving detailed information.

    The functional test is roughly for each devices in PCB, not checking the functions of TPS92515. The noise means audible noise around TPS92515 and Inductor. Perhaps, it's caused by boot capacitor refressh cycle.

    Thanks,

    Best Regards,
    Sam Lee
  • 0 in reply to Lee, Sam
    TI__Mastermind 28655 points

    Hello Sam,

    They can run this on the bench without a load and see what the SW node is doing.  If it is recycling the boot capacitor they will see that.

    Regards,