2kw pull-push offline smps

[eem2am]

powerbob:

This problem can be totally avoided by using a half bridge driver that has a capacitor in series with the primary winding to continually adjust transformer imbalance.

This has been widely discussed on this forum before

If you have a cap in series with pri then you MUST use voltage mode only.

And if you use voltage mode then what happens when it goes on overload.......well, it goes into cycle by cycle current limit, because all voltage mode half bridges need a pri current limit.......and when you go into cycle by cycle current limit then your half bridge rail splitter cap voltage drifts, which means you need to size the splitter caps for the full rail voltage which meakes them very very expensive.

Without a series cap you need to be in current mode with a half bridge.......but if in current mode then you need to have "average current mode" as per the LM5039....otherwise you rail splitter cap voltage will drift again

LM5039
http://www.ti.com/lit/ds/snvs621c/snvs621c.pdf

So i would choose full bridge over half bridge, unless you use the LM5039.