The 'MOSFET' diode idea is something I've used for several years now, and it works beautifully. The focus of the article is on the lower voltage drop in low-voltage applications, but it also works a treat in lowering dissipation in high power applications.

The scheme, as presented in the article, only works for voltages lower than 20V (the gate breakdown voltage of most MOSFETs), but can easily be adapted for higher voltages, with the addition of a zener diode, like so:


As good as this idea is, you must be aware of the fact that this is not a real diode! If the voltage on the source-side of the FET should become higher than the drain voltage, the FET will still be on.


Rob.