Bulk capacitor voltage rating

Posted by: ad_bg110 on 09/17/2009

I have designed an universal input type(90V AC to 300V AC) TOP245-GX based SMPS & PIexpert has suggested a 56mfd/400V bulk capacitor.

Now my question is why 400V? The peak voltage of a 300V AC is 300 X 1.414= 424V

So shouldn't the capacitor be rated for 450V instead of 400V ?

.............
Shantanu

Comments

You are correct. You should be using a 450 V capacitor.

Then can this be considered to be a bug in the PI Expert software that needs to be corrected?
..............
Shantanu

Yes if PIExpert says use a 400 V cap then this is a bug and needs to be corrected.

Thanks for the clarification.
..............
Shantanu