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Humming Noise in inductor in DC DC Buck converter

Question asked by manish31390 on Mar 30, 2015
Latest reply on Mar 30, 2015 by LucaV

Recently I design a DC-DC buck converter having switching freq approx 60khz with 33uH inductor and 20uF ceramic output capacitor( two cap placed in parallel). I am suffering from the humming noise coming from the inductor. What could be the reason for it?

 

I cannot control the switching freq of the converter as throughout my load conditions the freq remains almost constant.

I replaced the ceramic output capacitor with the same value of tantalum capacitor ( 20uF, two 10uF placed in parallel) then the noise goes off.
What could be the reason for this?

As the noise is coming from inductor and by changing the dielectric of the capacitor(ceramic changed to Tantalum) the noise goes off.

Can you please help me in understanding this phenomenon.

 

Thnaks in advance

Manish

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