I am looking at different options for implementing a fuel gauge/protection circuitry for a 4 series cells, 380mAh pack. I am already familiar with the BQ20Z655 but it states a restriction on the minimum capacity at 800mAh. I haven't found a good explanation for why this fuel gauge has a lower limit for its capacity.
For an alternative I was looking at using the BQ40Z50 or BQ76920. The webpage and datasheets don't show any restrictions on battery capacity. Can these chips be used for any capacity?
I suppose my main question is what is the limitation on many of the other fuel gauges that prevents them from being used with lower capacity packs? Is it the internal software or current sensing circuitry?