LTC4359 For 100V Application

D2 prevents Q1 from avalanching when OUT voltage rises due to an inductive load (relevant since your load is a motor).
This works in parallel with the snubber, which dampens ringing.

The 10Meg is a bleeder resistor for the GATE pin.
If input is suddenly disconnected, V_GS will settle to 0V, and Q1 will turn off.

In terms of your project, don't expect that by ORing multiple supplies they will share evenly. (known as "droop sharing")
Mismatch in supply voltage, cable resistance, etc, will cause one supply to carry most of the load.

-Aaron

D2 prevents Q1 from avalanching when OUT voltage rises due to an inductive load (relevant since your load is a motor).
This works in parallel with the snubber, which dampens ringing.

The 10Meg is a bleeder resistor for the GATE pin.
If input is suddenly disconnected, V_GS will settle to 0V, and Q1 will turn off.

In terms of your project, don't expect that by ORing multiple supplies they will share evenly. (known as "droop sharing")
Mismatch in supply voltage, cable resistance, etc, will cause one supply to carry most of the load.

-Aaron

Thank you very much! Im not too worried about load sharing between the ORing since LiPo batteries should be able to load balance. I am also planning to add a reverse polarity protection circuit before the ideal diode, and a load dump circuit that is triggered by the voltage spikes (anything above 130V) induced from motor braking to dissipate the braking energy at the output. A quick sketch of the circuit is attached below, can I get some input on the design?

Beautifully drawn circuit.
The reverse polarity protection section is redundant, as the LTC4359 will handle that function.
The  load dump circuit is creative, but I can't comment on how well it would work. I'd try using TVS first.

Thank you!

- In terms of reverse polarity, wouldn't current conduct from R4 through D2 back to the battery's negative terminal if Q2 wasn't there?

- Yea, if the braking current is big then R7 may not be able to handle it. TVS are able to handle micro-seconds transients, but will not be able to handle 300ms of braking energy. I'll think a little bit more on that part. 

- Regarding the snubber circuit, would you advise having a snubber per MOSFET in parallel, or just a single snubber circuit will do (I'm planning to parallel at least 7 MOSFETs to keep the temperature rise low using AOTL66518).