Hi!
We're seeing about 120mV of peak-to-peak noise across our .1mOhm current sense resistor (WSLP5931L1000FEA 1% tolerance, +300ppm/ºC). We're trying to figure out how it could be possible to get an accurate current measurement in this situation.
What is a typical sense resistor noise level for successful circuits using the BQ76952?
For example, since 1 amp across a .1mOhm resistor is .1mV, our signal to noise level is 1:1000. How could we expect to measure 1amp or 10amps or even 100amps. Even if we used a 1mOhm sense resistor (which is used in the example circuit in the data sheet) 1amp would be deep in the noise floor.
Is the calibration effective enough to make up for this extreme of a signal-to-noise ratio? Is there anything else we're missing?
We've done our best to minimize the noise by putting the sense resistor on a separate board in a metal enclosure. And we've added and experimented with multiple filter capacitors.
We're considering trying to integrate a hall effect sensor to replace the sense resistor. Would a hall effect sensor be more likely to measure a wide range of currents accurately? Do many manufacturers choose hall effect sensors over sense resistors?
Thanks for any help!
