The ISL9518, ISL9518A are highly integrated Narrow VDCsystem voltage regulators and battery charger controllers.Operating parameters are programmable over the SystemManagement Bus (SMBus). The ISL9518, ISL9518A aredesigned for applications where the system power source iseither the battery pack or the output of the regulator/charger.This makes the max voltage to the system equal to the maxbattery voltage instead of the max adapter voltage. TheISL9518, ISL9518A also include a system to control tricklecharging deeply discharged batteries while maintainingsystem voltage at a user defined minimum. High efficiency isachieved with a DC/DC synchronous-rectifier buck converter,equipped with diode emulation for enhanced light loadefficiency and AC-adapter boosting prevention. The ISL9518,ISL9518A can charge two to four series connectedLithium-ion cells, at up to 8A charge current. The ISL9518has default settings for 2-cell systems and the ISL9518A hasdefault settings for 3-cell systems. Integrated MOSFETdrivers and bootstrap diode result in fewer components andsmaller implementation area. Low offset current-senseamplifiers provide high accuracy.The ISL9518, ISL9518A provide two open drain digitaloutputs that indicate the presence of the AC adapter andtrickle charge state. Trickle charge state and AC adapterpresent indicators are also available via SMBus. TheISL9518, ISL9518A also provide two analog outputs thatindicate the adapter current and battery discharge currentwith 4% accuracy.