Despite helpful replies from both Jeremy and Yilcan Guzelgunler, I got nowhere.
And so, heroically, gave up.
Now I am having another go, removing the 100% duty cycle requirement to make things a bit easier.
So two n-fets are now allowed on the output, as is a bootstrap circuit to power the top fet.
However, the logic end of the circuit has now only got a Li-ion cell to run from – so I am expecting to use mosfets with a low gate threshold – and the thing still has to operate from a bridge supply of between 4 and 20V.
Operating frequency will be somewhere in the 50kHz-1MHz range.
A pair of 2A mosfets inside the package as well would be icing on the cake.
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