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TPS562200: high frequency sounds in DC-DC circuit with TPS562200.

Kyutae Kim
Intellectual 330 points
Part Number: TPS562200
Other Parts Discussed in Thread: TPS562209, TPS562208

Hi, All.

I've made 5V switching regulator circuit like attached diagram, and very high frequency sound is generated as the circuit provides 5V output.

It's very annoying, and what is worse the sound is amplified as the 5V is applied to an LCD board as an Vcc.

Could you check the attached, and provide me your idea where this sound noise come from, and how I can remove it?

  • 0
    TI__Expert 4875 points

    Hi Kyutae,

    The sound should coming from the vibration of the inductor. There could be two conditions that cause it. One is instability of the control loop and the other is the switching frequency drops to 20KHz. Since you component is selected according to Webench model, it should not because of instability. I am not sure whether your load is varying. TPS562200 is an eco mode part which will lower its frequency during light load. In your load condition, the frequency may drop below 20kHz and you could hear the sound from inductor. Please check on the frequency of SW node waveform and if it drops to 20kHz, then it should be the cause. In this case, you could increase the inductor further and it may increase the frequency a bit or you could switch to use fixed frequency device like TPS562208 or TPS562209. They will have the constant frequency under different load condition. Thanks!

    Best,

    Anthony

  • 0 in reply to Anthony Lang
    Intellectual 330 points

    Hi Anthony.

    Thanks for your help.

    For a clarification, do you think only changing the IC to TPS562208 or TPS562209 without other component changes in the circuit can solve this coil noise issue? Or should I have to check all the component as well with this IC change?

    Thanks and regards.

  • 0 in reply to Kyutae Kim
    TI__Expert 4875 points
    Hi Kyutae,

    TPS562208 and TPS562209 is BOM to BOM with TPS562200. You could directly replace the IC without other change.

    Best,
    Anthony
  • 0 in reply to Anthony Lang
    Intellectual 330 points
    Thanks, Anthony. I will replace the IC to check the issue!!