Ideal diode - PNP emitter-base breakdown voltage question (PMOSFET)
You are correct, as is, the left side of the circuit would conduct back if the right side was about 5.6V higher than the left side. Interestingly, the right side does not have this problem since the internal diode in the MOSFET keeps the voltage in check.

As such, when dealing with higher voltages the circuit needs to be augmented to prevent back driving through the comparator. When necessary it is also required that the gate voltage be limited within Vgs Max. 

The circuit below performs both functions up to the 30V limit of the BAT54C. R1 and R2 prevent a charge from building on Vbe when they are back biased. D3, along with R5, limits Vgs to 12V.







simulate this circuit &ndash; Schematic created using CircuitLab