The ISL6256, ISL6256A is a highly integrated battery charger
controller for Li-ion/Li-ion polymer batteries. High Efficiency is
achieved by a synchronous buck topology and the use of a
MOSFET, instead of a diode, for selecting power from the
adapter or battery. The low side MOSFET emulates a diode at
light loads to improve the light load efficiency and prevent
system bus boosting.
The constant output voltage can be selected for 2, 3 and 4
series Li-ion cells with 0.5% accuracy over-temperature. It can
also be programmed between 4.2V + 5%/cell and
4.2V - 5%/cell to optimize battery capacity. When supplying
the load and battery charger simultaneously, the input current
limit for the AC adapter is programmable to within 3%
accuracy to avoid overloading the AC adapter, and to allow
the system to make efficient use of available adapter power
for charging. It also has a wide range of programmable
charging current. The ISL6256, ISL6256A provides outputs
that are used to monitor the current drawn from the AC
adapter, and monitor for the presence of an AC adapter. The
ISL6256, ISL6256A automatically transitions from regulating
current mode to regulating voltage mode.
ISL6256, ISL6256A has a feature for automatic power source
selection by switching to the battery when the AC adapter is
removed or switching to the AC adapter when the AC adapter is
available. It also provides a DC adapter monitor to support
aircraft power applications with the option of no battery charging.

Features
• ±0.5% Charge Voltage Accuracy (-10°C to +100°C)
• ±3% Accurate Input Current Limit
• ±3% Accurate Battery Charge Current Limit
• ±25% Accurate Battery Trickle Charge Current Limit
• Programmable Charge Current Limit, Adapter Current
Limit and Charge Voltage
• Fixed 300kHz PWM Synchronous Buck Controller with
Diode Emulation at Light Load
• Overvoltage Protection
• Output for Current Drawn from AC Adapter
• AC Adapter Present Indicator
• Fast Input Current Limit Response
• Input Voltage Range 7V to 25V
• Support 2-, 3- and 4-Cells Battery Pack
• Up to 17.64V Battery-Voltage Set Point
• Control Adapter Power Source Select MOSFET
• Thermal Shutdown
• Aircraft Power Capable
• DC Adapter Present Indicator
• Battery Discharge MOSFET Control
• Less than 10µA Battery Leakage Current
• Supports Pulse Charging
• Pb-free (RoHS Compliant)

Applications
• Notebook, Desknote and Sub-notebook Computers
• Personal Digital Assistant