SLUSDF9 June 2020 BQ25790
The BQ25790 has two ACDRV drivers to control two optional sets of back-to-back power N-FETs, selecting and managing the power from two different input sources. In the POR sequence, the charger detects whether the ACFETs-RBFETs are present, then updates the ACRB1_STAT or ACRB2_STAT status bits accordingly. The ACFET1-RBFET1 or ACFET2-RBFET2 can be controlled by setting the register bit EN_ACDRV1 or EN_ACDRV2. If the external ACFET-RBFET is not present, then tie VAC1 / VAC2 to VBUS and connect ACDRV1 / ACDRV2 to GND. The power MUX drivers support three different application cases, which are elaborated in detail below.