Generation of overlapping 50:50 push pull signals for a cascaded buck-push-pull-converter.
Cascaded Buck-Push-Pull converters offer fast load regulation as well a sparing out some filter components, as the transformer acts as output inductor.
This topology is a current fed one and therefore the current flow may not abort. Push-Pull signals need a short overlapping time.
It took me some time figure out this easy way, after fiddling around with a SG3525 model and inverters...