To minimize power dissipation and voltage drop across the shunt resistor (RS), a value of 20mΩ is selected. Since the overcurrent level of 10A creates a 200mV drop across RS, R1 and R2 are calculated to create the voltage divider value of 200mV from the regulated 5V supply voltage. If the system is expected to operate close to the 10A maximum, hysteresis can be added to the design as shown in
Non-Inverting Comparator With Hysteresis.