Hi shichen717,
I have calculated Rsense in 4.7Ohm and I can use an ADC (ex. AD7789 with AIN(-) connected to AGND) without input buffer. Do you think I could have any problems on low voltage with such a resistor's value?
Could you please send me (if it isn't too much trouble) a basic schematic of the two versions of non-floating method, in order to help me better understand the two solutions you propose me?
Thank you