JAJSFS8 July 2018 BQ25601D
If only battery is present and the voltage is above depletion threshold (VBAT_DPL_RISE), the BATFET turns on and connects battery to system. The REGN stays off to minimize the quiescent current. The low RDSON of BATFET and the low quiescent current on BAT minimize the conduction loss and maximize the battery run time.
The device always monitors the discharge current through BATFET (Supplement Mode). When the system is overloaded or shorted (IBAT > IBATFET_OCP), the device turns off BATFET immediately and set BATFET_DIS bit to indicate BATFET is disabled until the input source plugs in again or one of the methods described in BATFET Enable (Exit Shipping Mode) is applied to re-enable BATFET.