LM5050MK-1EVAL: Why we need a Schotty diode in the Vin to Vout in the Or-ing controller design

Hi,

I am implementing the Or-ing controller for the redundant power supply application. 

In some circuitry, I see the Schotty diode between the input and out.

I have no idea what's the purpose of this design since the main idea of implementing the LM5050 is to replace the diode. 

Can you share the idea of it?

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