The BQ2461x uses a SLEEP comparator to determine the source of power on the VCC pin, because VCC can be supplied either from the battery or the adapter. If the VCC voltage is greater than the SRN voltage, BQ2461x enables the ACFET and disables BATFET. If all other conditions are met for charging, the BQ2461x then attempts to charge the battery (see Enable and Disable Charging). If the SRN voltage is greater than VCC, indicating that the battery is the power source, the BQ2461x enables the BATFET and enters a low quiescent current (<15 μA) SLEEP mode to minimize current drain from the battery.
If VCC is below the UVLO threshold, the device is disabled, ACFET turns off and BATFET turns on.