ISL6257

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
• 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
• Support Pulse Charging
• Charge any Battery Chemistry: Li-Ion, NiCd, NiMH, etc.
• Pb-Free Plus Anneal Available (RoHS Compliant)




Application

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




Pinout






Specifications

DCIN, CSIP, CSON to GND. . . . . . . . . . . . . . . . . . . -0.3V to +28V
CSIP-CSIN, CSOP-CSON. . . . . . . . . . . . . . . . . . . -0.3V to +0.3V
CSIP-SGATE, CSIP-BGATE . . . . . . . . . . . . . . . . . .. . -0.3V to 16V
PHASE to GND . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . -7V to 30V
BOOT to GND . . . . . . . . . . . . . . . . . . . . . . . .. . . . -0.3V to +35V
BOOT to VDDP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -2V to 28V
ACLIM, ACPRN, CHLIM, DCPRN, VDD to GND. . . . . . . -0.3V to 7V
BOOT-PHASE, VDDP-PGND . . . . . . . . . . . . . . . . . . . . . -0.3V to 7V
ACSET and DCSET to GND (Note 1) . . . . . . . -0.3V to VDD + 0.3V
FB, ICOMP, VCOMP to GND. . . . . . . . . . . . . . -0.3V to VDD + 0.3V
VREF, CELLS to GND . . . . . . . . . . . . . . . . . . -0.3V to VDD + 0.3V
EN, VADJ, PGND to GND . . . . . . . . . . . . . . . . -0.3V to VDD + 0.3V
UGATE. . . . . . . . . . . . . . . . . . . . . . . PHASE-0.3V to BOOT + 0.3V
LGATE . . . . . . . . . . . . . . . . . . . . . . . . PGND-0.3V to VDDP + 0.3V
PGND to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +0.3V




Description

The ISL6257 is a highly integrated battery charger controller for Li-Ion/Li-Ion polymer batteries. ISL6257 is designed for Narrow VDC applications where the system power source is either the battery pack or the regulated output of the charger. This makes the max voltage to the system equal to the max battery voltage instead of the max adapter voltage. Operating at lower system voltage can improve overall efficiency. High efficiency is achieved in the charger with a synchronous buck topology. 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% per cell and 4.2V - 5% per 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 ISL6257 automatically transitions from regulating current mode to regulating voltage mode.