SLUSCU0I March 2018 – September 2020 BQ77915
When the CHG driver is off, CHG is pulled to VSS, the PACK– terminal can be pulled up to the PACK+ level when a load is connected. This can put the gate-source voltage above the absolute max of the MOSFET rating. Thus, it is common to place a Zener diode across the CHG FET’s gate source to protect the CHG FET. Additional components are added when a Zener is used to limit current going into the CHG pin, as well as reducing the impact on rise time. See Figure 10-4 for details.