Why RC snubber is not recommended for the diode in the secondary output

[mh17]

I am using Viper27HD integrated circuit. RC snubber structure is not recommended for the diode in the secondary output on the datasheet and edesignsuite.

Resonance occurs between the secondary leakage inductance of the transformer and the parasitic capacitance of the diode and the peak level increases even more in the reverse voltage and damages the diode.

Why RC snubber is not recommended for the diode in the secondary output?

 

[Peter BENSCH]

Welcome @mh17, to the community!

The data sheet does not show a finished construction proposal, but provides recommendations. A snubber above the output diode that you have marked here can be provided if the reverse voltage of this diode is close to the output voltage. However, such a snubber can also be omitted if the reverse voltage is selected appropriately. However, it must be taken into account that Schottky diodes, for example, also have a higher forward voltage with a higher reverse voltage, which in turn reduces the efficiency of the converter.

Ultimately, it is always a decision for the project developer, who has to weigh up efficiency, costs and other parameters.

Hope that answers your question?

Regards
/Peter