This is an example of how a bootstrap can be used to convert a 5V signal to a signal much stronger than the high voltage at the MOSFETs drain. (Or is it source? Either way, I mean the equivalent of the BJT’s emitter.) That way, the MOSFET can be turned on fully without any voltage drop and without a p-channel one being used. Because of this there is a voltage drop of half a volt at 50 amps. This equates to only 25W dissipation for 50A.
