Hi,
Please spell out regarding the particular of a buck circuit you want to indulge with. Input voltage, output power and voltage requirement etc. then help can be provided.Even a detail circuit also can be provided. Thanks.
There are two points contradicting usage of UC3843 and similar in this case.
- A level shifting driver with boostrap function would be needed
- There's no simple way to connect the current measurement, that is expected for current mode operation.
In my opinion, it's much simpler to use one of various available buck converter controllers for an external NFET switch.
As FvM mentionned, you need a level shifting circuit between this driver and your MOSFET.
You can do it using a transformer, this will help you to get a floating node voltage to the MOSFET gate.
A transformer 1:1 turns ratio is usually sufficient.