Current sensing in a 500W Full Bridge SMPS

[Faringdon]

Hi,
Do you agree, in the attached 500W Full Bridge (28Vout, FSW=250kHz), Position 2 is a better place for the overcurrent sense than Position 1?
(LTspice and jpeg attached)

(But of course, as we all know, that a Full wave rectified current sense would have been better, in Position 1.....but we are being told, the way its done uses one rectifier diode instead of 4)

[T3sl4co1l]

Neither..?!

Tim

[Faringdon]

Thanks, so you  prefer bipolar CST with full bridge diodes output in position 1?
That would be my argument, but i am being told its three more diodes.

[T3sl4co1l]

I'd do it on the primary side (CT into FWB), or secondary with a DC shunt with control circuit secondary referred.  Perhaps both.  Possibly with a GDT ala ye olde TL494 circuit.

But doing an LLC is more feasible than ever these days, and current limit is somewhat free there.

Tim

[jonpaul]

at 500 W a double Foward is much simpler, full bridge unnecessary

J