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berkeman
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Aug18-08, 11:45 AM
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Quote Quote by ElectroPhysics View Post
I have a problem with my switch mode power supply, smps. It creates audio sound when I power it up, especially at minimum load. As I increase the load then sound disappears and in some designs it is still there. I don't know what to do. It is a bottleneck for me. Anyone who knows what to do about it. I'm operating it at 50KHz which is well above audio frequency.
Most likely it is magnetostriction noise in your main switching magnetic component. What topology is your SMPS? What transformer/inductor are you using? The general fix/prevention is to put some epoxy material in the gap of your transformer. Who is your transformer/inductor supplier?