Author Topic: How to eliminate acoustic noise in high current circuits?  (Read 171 times)

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Offline MikeLemon

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Hello there,

In every circuit I build with a simple switching mosfet at 10KHZ+ with 5A+ (to around 40A) I get audio able noises even tough I don't use any inductive components like inductors and such.

Any hint on how to eliminate such noises?

Thanks for helping.
 

Offline hlavac

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Re: How to eliminate acoustic noise in high current circuits?
« Reply #1 on: Yesterday at 03:03:56 am »
Ceramic caps making the noise?
Easiest fix may be to move up the switching frequency above 25kHz...
Good enough is the enemy of the best.
 

Offline SiliconWizard

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Re: How to eliminate acoustic noise in high current circuits?
« Reply #2 on: Yesterday at 03:31:29 am »
Yes ceramic caps can be pretty noisy especially SMD ones, transmitting vibration to the PCB they are soldered on.

A few pointers:
https://www.edn.com/design/components-and-packaging/4364020/Reduce-acoustic-noise-from-capacitors

Now if you don't use any ceramic cap in the power section we'll have to look elsewhere obviously.
 

Offline tpowell1830

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Re: How to eliminate acoustic noise in high current circuits?
« Reply #3 on: Yesterday at 03:40:01 am »
Could also be board layout, the traces are inductors and the PCB is a sounding board?

Potting could reduce the noise.
PEACE===>T
 

Offline SeanB

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Re: How to eliminate acoustic noise in high current circuits?
« Reply #4 on: Yesterday at 04:51:37 am »
Traces near a steel chassis, where you get nice magnetic forces turning the chassis into a speaker.
 

Offline ejeffrey

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Re: How to eliminate acoustic noise in high current circuits?
« Reply #5 on: Yesterday at 06:04:29 am »
Also remember that your circuit includes the part *before* the switch too.  If you have inductors or capacitors on the input/supply side they can make noise just as well as the load side.
 


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