The SMBus clock and data lines have internal pulldown. When the gas gauge senses that both lines are low (such as during removal of the pack), the device performs auto-offset calibration and then goes into SLEEP mode to conserve power.
In SLEEP mode, the BQ40Z50 performs measurements, calculations, protection decisions, and data updates in adjustable time intervals. Between these intervals, the BQ40Z50 is in a reduced power stage. The BQ40Z50 has a wake function that enables exit from SLEEP mode when current flow or failure is detected.
