The ISL95522 is a highly versatile combination battery charger configurable for operating as either a Hybrid Power Boost (HPB) charger or a Narrow VDC (NVDC) charger, supporting 2-, 3-, or 4-cell batteries. Both configurations allow the battery to work with the adapter to supply the system load when it exceeds the adapter capability, referred to as system Turbo mode. The HPB charger configuration reverse-boosts battery energy to the system bus to help the adapter provide the system power in Turbo mode. The NVDC charger configuration quickly turns on BGATE, which enables the battery to help the adapter provide the system power in Turbo mode.