How to protect reverse polarized when there are two different power sources

Question

The meaning of the title is, when connecting a DC buck converter and a lithium-ion battery, to ask how to protect the converter from the reverse polarity of the battery

first i will use ideal diode like this answer in this post

So it will cut off the current from the battery

and next things to consider is reverse polarity protection

I was trying to find some circuit examples on the internet and found a similar example circuit with battery charger reverse polarity protection

I just can't use the example circuit because I'm planning a 30V output and equivalent battery series connection or normal load(other circuit or something else)

Another problem is that the second power source is charging the gate of N mosfet, so no power is provided to the load when connecting a resistor to this circuit

I thought about using a optocoupler

what about this circuit

I have simulated the circuit here

optocoupler is activate only when the second supply is connected in reverse polarity

No matter how much I think about it

it too difficult if the electric potential of the two power sources is not separated

it look okay?

I'm worried that the high voltage will destroy the device

and I wonder if there is a better circuit

i need some feedback

thank you for your attention

Answer 1

What you need is some kind of oring controller. They are just like ideal diodes but with more than one input. Each source is usually gated with back to back MOSFETs and there is some logic that chooses which source connect to the output (often simply the higher voltage one). You could do it in discretes but they are quite cheap to buy.