[PStechPaul]

Rereading your post, I thought you meant metal oxide varistors, rather than resistors. And I'm just not familiar with the topology shown in the link. I found a similar half-bridge circuit in the following app note, but it does not have the third capacitor, which I think may be superfluous:
http://www.st.com/internet/com/TECHN...CD00003910.pdf

For my own purposes, I am planning to use a push-pull topology, for a step-up DC-DC converter. And I do not need regulation, so the PWM can be nearly 50% which makes almost pure DC after the FWB. The DC-DC converter being discussed here is used to convert the battery pack voltage of 144-300V or so, to 12VDC for the accessory battery. This is a new concept for me, so I don't have a good grasp of what is really needed and why these converters are designed as they are.