Cross regulation in flyback?

[grizedale]

Hi

I am doing an offline flyback at 50W.

There is a split rail of +/-35V (+/- 2v) (at 40W)

Also there is a 5V, 20W rail which needs to be 4.5V to 5.5V absolute max

Is it ever advisable to do such a thing without a secondary side smps to give the 5V.

I would have thought cross regulation would never be good enough to give the required 5V output with sufficient accuracy?

 

[atripathi]

You can give a try with tighter coupling between all windings, and making 5V output as primary control point.