TINA/Spice/UCC28950: In the smps examples folder, for steady state UCC28950 why does replacing the synchronous rectification with a diode bridge not give the same output.

Tool/software: TINA-TI or Spice Models

Hello everyone,

I am trying to simulate my smps design which incorporates a 2 winding transformer along with a diode bridge instead of the center tapped transformer with synchronous rectification. 

When I delete the synchronous rectification portion of the model and replace it with a diode bridge and connect the two inner windings of the transformer and double the ratio, I assumed this would give me the same output, but instead Vo just keeps decreasing

Does anyone have a method to simulate a 2 winding transformer (one primary, one secondary) with a diode bridge?  Ideal transformer doesn't work either.

Here's a picture of my attempt.