Brownout function with LinkSwitch-CV

First, I apologize for my English, it's not at a good level.
I use LNK623D in my design.
Study of the functional block diagram suggests that if I hold the FB output at zero level, then the switching of power MOSFET disabled and output voltage removed.
How this conclusion is correct and acceptable use of the FB output circuit in this mode?
May be ready circuit decisions for implementing brownout function with LinkSwitch-CV family?

Thanks,
Andrei Skvortsov