Right now circuit is non isolated logic ground and power ground is star connectedIR2110 doesn't provide isolation between VSS and COM, only a level shifter and a few volts compliance. In so far it's no safety feature, but can possibly avoid interference between output stage and logic. A galvanic connection between DC- and logic ground is required. Depends on your layout if you can take advantage of separate ground pins.
FAN7380 has very weak drive...said to be for CF lamps etc.
I m using ir2110 for 110vac acim at 2khz pwmHi,
FANxxx is 8 pin IC,
IR2110 is 14/16 pin IC.
With 8 pins you are limited in IOs.
I agree with FvM.
If you need a more detailed answer we need to know more details about your application.
In your current application, how much voltage difference ( peak peak) do you expect between COM and VSS?
A schematic and a PCB layout whould be helpful.
May I ask why you choose FAN7380 ... when you are not satisfied with it?