Flyback dc to dc converter switching frequency

Thread Starter

JMS026

Joined Oct 1, 2015
3
Hello friends, I am working on a project where I used flyback dc to dc converter to power up all circuit components.
My issue is related to switching frequency. When I use 100KHz switching frequency(using TOP Switch) my circuit works properly but when I switch to 400KHz (using DPA switch) the issue of noise interference in secondary side is started.

Is there any trend to use special filter capacitor/inductor at special locations to avoid primary sided noise from coupling with secondary sided circuit?
 

DickCappels

Joined Aug 21, 2008
10,152
Yes, there are three-legged filters to clean up very high frequency noise.

Yes, your schematic is important.

Do you know how the noise gets from the power supply primary to the circuit that is experiencing the interference? There are many possible paths besides through the rectifier on the transformer's output and the higher the frequency the more significant these sneak paths become (magnetic induction of the signal into the chassis, capacitive coupling of high dv/dt electric fields, ground loops, etc.
 
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