SLUSDF9 June 2020 BQ25790
If only battery is present and the voltage is above UVLO threshold (VBAT_UVLOZ), the BATFET turns on and connects the battery to the system through the internal BATFET. The REGN LDO stays off to minimize the quiescent current. The low RDS(ON) of BATFET and the low quiescent current on BAT minimize the conduction loss and maximize the battery run time. The device always monitors discharge current through the BATFET.