What is the point / name of this circuit? Reverse voltage protection + current mirror?
What is the point / name of this circuit?

The name of the circuit is an &quot;ideal diode&quot;.
The point of the circuit is to conduct current in one direction only, like a diode, but to have a minimal forward voltage drop.
It is often used when combining multiple power supplies or sources, where the voltage drop of a conventional diode is undesirable.
It could also be used to protect a circuit from reverse applied voltage.
The principle of operation of this particular &quot;ideal diode&quot; is that if the voltage on emitter of Q1 is greater than the voltage on the emitter of Q2, the gate of M1 will be brought low, and M1 will conduct.
Addendum: This Power Electronoics Tips Article supplied to me by @Grant gives further details.