I was building an ESC. Motor V=22V max current I=90A Battery max current I=60A. My controller is a MIC4607 (Datasheet:http://ww1.microchip.com/downloads/en/DeviceDoc/20005610B.pdf) The PWM f=16kHz but i will try to get 20kHz later. As you see there is a RSNS resistor, which is conected to the Source of the MOSFETs and to the MIC4607, where ILIM+ and ILIM- is a comparator which would trigger if the voltage rises above 200mV and turn all High-Side MOSFETs off. I want to use this function to protect my Batteries and Motor from overcurrent.
My Question is how do I do that. I would need a SHUNT resistor but they are very bulky. I found SMD shunts https://www.mouser.it/ProductDetail/KOA-Speer/PSJ2NTEB1L00F?qs=sGAEpiMZZMtlleCFQhR%2fzfOI4xHs7IDUutBqgYbi4Il52bsccUJZvA%3d%3d this one has 1mOhm resistence and could withstand the amps P=I^2*R would be 3.6W. Is this possible? The Voltagedrop over it would be only 60mV but i could amplify it. An other solution would be the measure the current at the Battery with the currentsensors of Alegro, up to 100A bidirectional and just apply a voltage to IlIM+ if the current excides the max allowed current, that would instantly switch off the MOSFETs.