I know that current shunt monitor ICs and high common-mode voltage differential amplifiers like the INA117 and AD629 exist but I'd like to know if it's possible to use a regular instrumentation amplifier where its input range is bounded by its power supply (e.g. AD623, INA177) and pre-attenuate the common-mode voltage using discrete or semidiscrete components.
I thought that using a voltage divider on the input and then compensating the gain factor proportionally would work if the in-amp has a high enough CMRR for the desired input range. I vaguely suspect that it's not that simple. If so, are there other (better) options to do this? I read something about using a current mirror but I don't really understand how that applies in this case.