SLUSDF9 June 2020 BQ25790
In order to provide an output voltage on SYS, the device requires a power supply between 3.6 V and 24 V input with recommended >500mA current rating connected to VBUS or a 1s to 4s Li-Ion battery with voltage higher than VBAT_UVLO connected to BAT. The source current rating needs to be at least 3A for the buck-boost converter of the charger to provide maximum output power to SYS.
The charger does not support the testing condition when the battery connection is floating. The BAT pin has to be connected to a real battery or some devices which can emulate the battery, like the battery emulator or bulk capacitors. When the BAT pin is floating, please disable charge by setting EN_CHG to 0 or pulling low the EC pin. Otherwise, the voltage overshoot at SYS might trigger the SYSOVP protection periodically.