Knowingly, BQ76942 has it's own current sensing capability with SRP and SRN, allowing to measure on a current sense resistor in the range of +-200mV (higher with fault current).
In my application low side current sense resistor is not feasible.
I need to be able to measure 250A peaks (fault current) and about 100A-175A continuous (@26Vbat max).
With a current sense resistor of 1mR, the resistor would dissipate roughly 30.6W and 62.5W peak - not feasible due to space constraints of such sense resistor and just can't allow that power loss continuously.
I was thinking if I could keep the power loss through current sense path low but still manage to use the BQ functionality.
1. Would it be possible NOT to use BQ76942's current sense pins, but use f.i a Hall Effect current sensor (<100uR series resistance), interface this to a microcontroller and via I2C communicate the current value to BQ76942 ?
This way to I'd hope to keep BQ informed about the current and still be able to use built-in features ?
2. Instead use still a Hall Effect current sensor, but convert it's output range (+-2.5V) to +-200mV to the BQ76942's SRP and SRN ?
I imagine this to be more 'autonomous', if smth were to happen with the uC, the current can still be measured.
Or
in Your humble experience, is there any other solution to allow the least power loss when sensing high current but still have BQ's protection and measurement features?