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TPS54560: Noise issue while testing with load.

Part Number: TPS54560


I have designed a circuit using TPS54560BQDDARQ1 DC DC convertor operating input voltage is 26V to 28V. Output voltage designed is 24V.
The circuit is same which was given in the TI Webench designer tool.

The circuit works fine at load and no load condition.

Issue : There is a hissing sound coming from the circuit when the load is connected. At no load condition its works fine. 

Please advice so that i can solve this issue.

Thanks in advance

  • Hi,

    It sounds like the circuit is regulating and operating properly at both no load and with load at steady state.

    Generally there are two components that can be the source of hissing/whinning in a step down circuit. The first one is the output capacitor and the second one is the inductor.

    First can you let me know what the schematic looks like so I can get a rough idea of what your system circuit is? Also can you provide the SW waveform at both load load and at load to help me get an idea of what the SW behavior of the converter is at the hissing/buzzing condition? 

    The hissing may be coming from the piezo-electric effects on the capacitor. This can go away if you reduce the capacitor ESR by using MLCC with low ESR.

    If it is the inductor then this may be due to mechanical resonance of the component by the electrical condition of your circuit. Either changing the switching frequency is often the best way to eliminate the noise or using a larger component with more mechanical dampening will help dampen or shift the audible resonance to a different frequency.



  • Hey, 

    Thanks for the reply. 

    I have attached the image of the circuit. Please check. 

    I have also sent the snap of SW signal at Load and No load conditions. 

    Please find the design link below.
    Power Designer (

    At Load Condition SW signal
    AT Load Condition SW signals

    Signal looks fine.

    At Load Condition SW Signals

  • Hi Harshith, Jimmy is out so I will respond.

    Your SW node looks fuzzy, there should not be a peak-peak of 4.8V in no load. 

    What are the exact part numbers you are using for CIN, COUT and L1 and D1?

    Also please share the pdf output of the webench report. That link goes to a default design.


  • Hi,

    We have not heard back from you for some time and assume that you were able to resolve the issue on your end.

    If you have any remaining questions, please comment and the thread will reopen for further discussion.

    Thank you for using the E2E forum.