I figured I might ask on here before trying to reinvent the wheel. I am using a buck converter (4A average output load, LTC3835 controller) and want the voltage regulated at 5V across 6 feet of cable (3 feet on the power line, and 3 feet on the ground line). I don't have the option to use thicker wire, so I was going to run some sense lines out to the load.
I think the best approach is to use a difference amplifier to subtract the power and ground sense lines and feed that voltage to the feedback resistors. I used LTSpice to simulate a DC operating point using 5V and 1V into the difference amplifier and the output comes out to be 4V.
Does anyone have any experience doing this? Am I going to mess up the control loop by adding this external difference amplifier? Suggestions?