Hbridge transformer driving series cap

[Jamie Morken]

Hi,

I am driving a transformer with an Hbridge, like this circuit:

http://www.hills2.u-net.com/electron/fullbrdg.gif

I am wondering about using a series cap on the transformers primary,
if it is necessary or not. I am using an FPGA to control the fets
gates, so should be able to keep the on times of one Hbridge leg very
close to the on time of the opposite Hbridge leg to minimize the
DC current in the transformers primary, but can the flux build up and
saturate the transformer without a series cap?

cheers,
Jamie