I want to use negative power supply to ensure the output can go down to zero on a low side current sense opamp. The prolem is if current flows in the oppozitte direction. then we have negative voltage on the output going to the ADC. The ADC is a part of a PIC MCU and it has diode to ground, so I can put current limiting resistor (1k - pic will work with up to 10k voltage source resistance) and it should be fine. But is there any other way to make sure the output voltage doesn't go much below 0V.
P.S. Current can flow in the opposite direction in few ways - if R1 is a battery being charged, if R1 has a big capacitor and the V1 goes down by few volts.