The BQ25790 is a fully integrated switch-mode buck-boost charger for 1-4 cell Li-ion battery and Li-polymer battery. The integration includes 4 switching MOSFETs (Q1, Q2, Q3, Q4), input and charging current sensing circuits, the battery FET (QBAT) and all the loop compensation of the buck-boost converter. It provides high power density and design flexibility to charge batteries across the full input voltage range for USB Type-C™ and USB power delivery (USB-PD) applications such as smart phone, tablet and other portable devices.

The charger supports the narrow VDC power path management, in which the system is regulated at a voltage slightly higher than the battery voltage, but not drop below the minimum system voltage. The system keeps operating even when the battery is completely discharged or removed. When load power exceeds input source rating, the battery gets into supplement mode and prevents the input source from being overloaded and the system from crashing.

The device charges a battery from a wide range of the input sources including legacy USB adapter to high voltage USB PD adapter and traditional barrel adapter. The charger automatically sets converter to be buck, boost or buck-boost configurations based on input voltage and battery voltage without the host control. The dual input source selector manages the power flowing from two different input sources. The inputs selection is controlled by the host through I2C with default source #1 (VAC1) as the primary input and the source #2 (VAC2) as the secondary input.Read more