SLUSDF9 June 2020 BQ25790
The charger enters HIZ mode when EN_HIZ bit is set to 1. The HIZ mode refers to a charger state, in which the REGN LDO is off, and the converter stops switching even if the adapter is present. Similar to the battery only condition, the charger is in a low quiescent current mode, turns off the ADC and turns on the BATFET to support the system load.
Some of the faults like VBUS_OVP, VSYS_OVP, VBAT_OVP and OTG_OVP, force only the converter to stop switching but keep the REGN on. While some of the faults like VSYS_SHORT and IBUS_OCP, force the charger into HIZ mode by setting EN_HIZ=1. More details could be found in the fault protection section.