Using synchronous rectifers with fullbridge smps with full diode bridge at secondary?

[treez]

Hello,
I wish to do a 850W full bridge with vin = 28v and vout = 34v.

I wish to use synchronous rectifiers in a full diode bridge secondary, (as in the schematic below) but its not possible to use Bootstrap high side gate driver IC's (eg LTC4440) for the high side sync rectifiers. Or am I wrong about this?

I believe that the bootstrap refresh circuit just wont work in the full diode bridge configuration as in the below schematic, is there any way of using such bootstrap high side fet driver ICs with a full diode bridge output?

LTC3901 datasheet (sync rectifier controller)...
http://cds.linear.com/docs/en/datasheet/3901f.pdf

LTC4440 bootstrap high side fet driver IC...
http://cds.linear.com/docs/en/datasheet/4440fa.pdf

 

[FvM]

I don't see why bootstrap shouldn't work. There's no functional difference between synchronous rectifier and H-bridge in active quadrants, except for current polarity.

 

[treez]

I don't suppose you have any idea why this LTspice simulation of the LTC3723-1 bridge controller and LTC3901 synchronous rectifier controller wont work?
(LTspice sim and schematic attached)

LTC3901 datasheet
http://cds.linear.com/docs/en/datasheet/3901f.pdf

LTC3723-1 datasheet
http://cds.linear.com/docs/en/datasheet/372312f.pdf

 

[FvM]

Both the current sense and the synchronization of secondary switchers aren't working correctly.

The current sense apparently triggers the overload comparator periodically.

The synchronization pulse transformer seems to ruin the waveform.