Hi,
Why is this LTspice sim not regulating...its an attempt to regulate the output current.
Top FET getting turned on continuously.....a bootstrap driver cant do 100% duty , so why does it try to?
It is not likely to be the fault of LTspice. Let us start with what you are trying to do. If you are trying to get a fixed current into a load, then you need to provide for a voltage that will allow Ohm's law to be satisfied. Are you doing that?
Looks to me as though the load current is being regulated to about 4.8A, with the IC going into hiccup mode to do that.
Why aren't you relying on the chip's current sense amplifier to do the limiting, rather than using all that stuff you've encircled?
What load current are you aiming for?