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TPS55340: Audible noise from the circuit

Chase Jeong
Genius 5000 points
Part Number: TPS55340

Hello TI experts,

My customer made PCB with TPS55340, and they found that there is an audible noise around TPS55340.

first here is the schematic.

(input is 8V, and output is 16.5V/2A)

we already tested with power supply, input and output. so it is the problem of TPS55340 and the components around.

and here are the things what we tested.

1. change the value of inductor -> 6.8uH, 4.7uH, 3.3uH

2. change the value of output capacitor -> totally 20uF and 10uF

3. change the value of R and C of comp pin (based on the E2E thread below)

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/581991/tps55340-tps55340evm-147-sepic-application-question

but there is still audible noise even we tried these 3 methods.

is there anything that we can remove this noise?

and please let me know if you need more information about this. Thanks.

Best regards,

Chase

  • 0
    TI__Mastermind 19130 points

    Hi Chase,

    Sorry to hear that you are having noise issues with the TPS55340 circuit.

    First of all, what load conditions is this in? 

    Secondly, can you check to see if there is any vibrations coming from the components itself, such as the inductor? 

    Thanks,

    Richard 

  • 0 in reply to Richard Fu22
    Genius 5000 points

    Dear Richard,

    Thank you for your support. Actually Here was lunar new year's holidays.

    anyway I answer your additional question.

    1. the load of the output is about 16.5V/2A. input is 8V.

    2. there was not recognizable vibration on TPS54330, inductor and capacitor when contacting it.

    and here is another condition, the input is not constant, it is on during 50ms, and off on during 50ms, so the frequency is 10Hz.

    is it possible to make a audible noise in this condition? what if I change the frequency like 1KHz or higher? would it still have audible noise?

    Best regards,

    Chase

  • 0 in reply to Chase Jeong
    Genius 5000 points

    Dear Richard,

    Please let me know if there are any updates about the issue above.

    and here are more results that the customer tested;

    - they did not hear any audible noise if the input is constant. (not 10Hz pulse.)

    - they did not hear any noise too, if the pulse is over 1Hz.

    so my thinking is that if the frequency of input voltage is matched to make some resonance, we hear audible noise. does it make sense?

    please find some history about it, and it would be very helpful if there are any formula or reference document about it.

    Best regards,

    Chase

  • 0 in reply to Chase Jeong
    Genius 5000 points

    Dear Richard,

    Please let me know if there are any updates about the issue above.

    It would be very happy if you give me some advices to solve this problem.

    Best regards,

    Chase