Current Sensing with Op Amps

I'm designing a current sensor for a switching regulator circuit (MAX668 run at 8V0 output) and I want to monitor the output current. I'm going to probably measure across a FET and then sense the current using an op amp and then another op amp as a comparator with one input being op amp1 and the second input being FPGA signal. I'm going to send this signal back to my FPGA.

The purpose of using the FET is so that I can shut off the output in the case of over current.

My question is regarding the amount of resistors required in this design. I know that the general design looks something like the image attached. I know the voltage divider can scale the gain but are R3 and R4 necessary?

I want to use the fewest amount of resistors possible.

Thanks!

Hi Jonathan,

Yes, it serves as gain controller without that op amps will simply saturate in its supply rails.

Op amps has a massive amplification and with that it is unpredictable without a feedback.

It can damage some of the component connected to it.

Hope it helps.

God Bless.

Best,
Neil