Your homework: What configuration is the current sense amplifier opamp, and what is the gain?
How many volts per amp of current (V = IR) will come out of the resistor, and the opamp, respectively?
What voltage is being fed in to the current limit opamp to be compared to the current sense amplifier output, and what does it in fact try to regulate the current to since you know the voltage ratios? (random example: non-inverting = 1V, inverting input = 0.1V, and if at 1V per A, therefor it strives for a 100mA limit.)
Why may a low value resistor be useful when high currents are used? Burden voltage, is a key term.
Would it be possible to add a bypass NPN to increase the current to 3-5 A?
As long as the return path includes the sense resistor, I do not see why not!
Tiger.