The ISL6256, ISL6256A is a highly integrated battery chargercontroller for Li-ion/Li-ion polymer batteries. High Efficiency isachieved by a synchronous buck topology and the use of aMOSFET, instead of a diode, for selecting power from theadapter or battery. The low side MOSFET emulates a diode atlight loads to improve the light load efficiency and preventsystem bus boosting.The constant output voltage can be selected for 2, 3 and 4series Li-ion cells with 0.5% accuracy over-temperature. It canalso be programmed between 4.2V + 5%/cell and4.2V - 5%/cell to optimize battery capacity. When supplyingthe load and battery charger simultaneously, the input currentlimit for the AC adapter is programmable to within 3%accuracy to avoid overloading the AC adapter, and to allowthe system to make efficient use of available adapter powerfor charging. It also has a wide range of programmablecharging current. The ISL6256, ISL6256A provides outputsthat are used to monitor the current drawn from the ACadapter, and monitor for the presence of an AC adapter. TheISL6256, ISL6256A automatically transitions from regulatingcurrent mode to regulating voltage mode.ISL6256, ISL6256A has a feature for automatic power sourceselection by switching to the battery when the AC adapter isremoved or switching to the AC adapter when the AC adapteris available. It also provides a DC adapter monitor to supportaircraft power applications with the option of no battery charging.