[mschuster91]

> The MOSFETs I'm using comes in a TO-220 package. The metal tab of the MOSFET is technically tied to its drain pin. Electrical isolation must be applied to avoid conduction between the other sets of MOSFETs. I usually leave the upper MOSFETs from the H-Bridge unisolated as they share a common drain pin (Vcc).

Oh holy, that's not good. If the screw threads manage to touch the inner side of the hole of the metal tab, you have electrical connection.

Besides that, I don't see a short-circuit protection on there - not sure if the "overcurrent" feedback can handle a dead short before the FETs blow up.