yes eric thats true,having a some mfd cap at bridge nad the scheme u said will do the job...even i did this in one of my design and it works well,but problem is that due to some other issues i can not use a cap in excess of .1,some software approach will have to be employed.

and as per mr gowrish question >>> i m using square wave with half bridge with center tap transformer,n ofcourse pwm is there.