Multi output flback cross regulation?

How about "none of the above" Try this:

) !! ---------- -12V ) !! ( ) !! ( ) !! ( ) !! -----+-->!--GND ) !! ! ) !! =3D=3D=3D C1 ) !! ! ) !! -----+-->!--+12V ) !! ( ) !! ( ) !! ( ) !! ------ ) !! ! ) !! ------+-->!---+5V ) !! ( ) !! ( ) !! ( ) !! ------GND ) !!

C1 ensures that the two 12V windings have the same AC waveform on them. This reduces the difference between the 12V supplies to the resistive drops. It also means that they both act to couple with the turns of the 5V.

In a non-isolated case making the design into a SEPIC by putting a capacitor from the primary to one of the secondary windings can help. The winding the capacitor hooks to should be the highest load one.

If you really want tight regulation, you can put a MOSFET in series with the 5V rectifier and switch it off when the 5V doesn't need more energy given to it. The +12 supply can be used to run the circuit that does this.

Thanks MooseFET

My +/- 12V doesn't have to be that tight of regulation +/- 10% is good enough. My 5V rail is supplying some expensive (for me anyways) op amps along with an additional -5V supply so that needs to be +/-

I'll proto it so I can test as many variations as possible.

I see I made a spelling mistake for flyback:) Whoops.

Do the -5 like I showed the +12 connected to the -12. This will hold them together tightly. You can regulate the +5 and get a fairly solid

-5.

If you continue both windings, to make the +12 and -12 you can't use the capacitor trick so the -12 has to have its own winding.

If you wanted 15V you could use 6 identical windings and hook them up as required.