I have this given circuit:
I can see by the look of it that this is a power rail "choosing" circuit. When
VBUS is applied and there is no
+5V, then the body diode of
Q1 simply conducts.
I am trying to understand what the logic behind this circuit is, when
+5V are supplied externally at the same time. I think that
Q1 is being turned off when
+5V is higher than
VBUS, but I can't explain it.
I would appreciate some hints, as I cannot really follow the scenario here with the