SLUSDV2A May 2020 – May 2021 BQ25798
When the device is powered up from VBUS, the LDO is turned on when VVBUS_PRESENT < VBUS < VVBUS_OVP. When the device is powered up from battery only condition, the LDO is turned on at either one of the following conditions:
The REGN LDO supplies internal bias circuits and the MOSFETs gate drivers. The pull-up rails of ILIM_HIZ, TS, and STAT can be connected to REGN. The INT pin pull-up rail is recommended to be an external 1.8V or 3.3V voltage source, rather than REGN, because at battery only condition, the REGN might not be available. Except the charger related pull up rails, the REGN is not recommended to source any other external circuit. The REGN has to power the internal MOSFETs gate drivers, which is very critical for the charger normal operation.