Active clamp flyback SMPS

[eem2am]

Has any reader tried to do an active clamp flyback to power a class D amplifier?

I cannot find a controller for it.....they all seem to be for active clamp forwards.

The leakage dissipation of a normal flyback at 350W is a pain......the clamp components need to be big.
-I have to say i reject use of DZ clamps, since TVS's are in "DO" packages, and these are simply NOT meant for continuous power dissipation of more then 1W, at the very most.

There is good reason why TVS diodes are not made in TO220 heatsinkable packages.....its because theyre not supposed to be used with continuous significant power.

[eem2am]

Actually i find controller for Active Clamp Flyback...UCC2891.

...However, i am disappointed in this topology.....it is advertised as ZVS.

But the ZVS only applies to the turn on of the fet....not the turn off.

....this is a little pointless in a flyback, because the turn-off switching loss is by far the worst........even in a normal flyback, the turn-on switching loss is snubbed by the leakage, so i cannot see much point in the active clamp flyback.....though i have to admit that turn-off switching losses will be a little reduced as the VDS at turn off isnt quite so high.