I'm designing a device that needs to take a wide range of analog readings and I'm trying to keep it to one microcontroller with multiple input ADCs. I need to measure voltages between 0 and 12V as well as currents. I also need to measure the voltage drop over a P-Channel high side FET with precision (it should be somewhere around 150mV).
I know I could measure the upper and lower voltages and subtract them but the tolerances on the resistors would not provide accurate enough results.
I'm wondering if there is a way to isolate the voltage differential and amplify it with respect to ground?