The Differential Amplifier
The differential input voltage rating is 32v, but my load supply is up to 80v. I have found more expensive current sense ICs that have input protection up to 500v, but I like the 324 because it's super cheap and comes in quad packages.
The actual voltage across the amplifier's inputs will not exceed very small values during sensing, and technically the two terminals of the 1mOhm sense resistor should never have more than 32v differential potential between them, but when idle, the high side resistor may have a difference of 80ish volts between the negative supply (GND) and the inputs.
Will this blow out the opamp? If so, can I use some clever diode protection trick to keep the opamp input voltage down?