I have some questions concerning the attached schematic.
 
What is the topology used here? I am guessing flyback without feedback circuitry! 

Why is the TPS40211 utilized here? is it to provide more current? Rather than using the 15V of the input this chip is used to provide more current for the gate drivers to drive the IGBTs (require +4A). am I right?

The transformer has 2 identical secondaries each one is used to drive the output of a gate driver, which require a bi-bolar power supply how can I use each secondary to provide both +15V and -15V?

There is a note in the Gate driver transformer datasheet: 'These gate drive transformers are meant to operate between 50 and 300 kHz with a 12V, 45% bipolar waveform'. Does that mean it can't operate at 15V?

The circuits are basically the same as the typical recommendation in datasheets but I couldn't figure out the connection between the 2 ICs.

[![enter image description here][1]][1]


The circuit goes something like this:
[![enter image description here][2]][2]

Thank you,


  [1]: https://i.sstatic.net/KGBpB.png
  [2]: https://i.sstatic.net/L73jP.png