Coupling factor of coupled output inductors is not important?

[treez]

Hello,
Please confirm that the coupling factor of coupled output inductors is not too important. That is, they do not need to be interleave wound.
The below simulation in LTspice shows a full bridge smps with a +/-40V output with coupled output inductors, which improve cross regulation in the +/-40V rails.

 

[FvM]

I'm not sure what you want to see in this simulation? There won't be no voltage asymmetry with symmetrical load. Secondly, if the load is large enough to achieve CM operation of the output inductors, the output voltage is roughly reproducing the average of rectified AC voltage and thus both outputs are still coupled despite of load asymmetry. But in DCM, inductor coupling becomes important.

 

[treez]

the loads are resistors of the same value here, but its actually going to be an half bridge audio amplifier. I am not sure if that represents a symmetrical load.

I hear you say that Coupled inductors are good for DCM case, but the following article does not make mention of that, it merely says that coupled inductors are required for smps's with more than one output in order to get good cross regulation
(part 5 of LHS of page 3)
https://www.ti.com/lit/an/slua119/slua119.pdf


..it doesn't say that the coupled inductors are only useful in DCM.

 

[FvM]

A halfbridge audio amp load is only symmetrical on average, low frequency output signals are "bouncing" the load between both supply nodes.