ISL6291

® ISL6291 Data Sheet November 2003 FN9102.1 Li-ion/Li Polymer Linear Battery Charger The ISL6291 provides a low-cost integrated charger solution for single-cell Li-ion and Li Polymer rechargeable batteries. No external pass element, current sensing resistor, or reverse blocking diode is required with this solution. The ISL6291 is a constant-current (CC)/constant-voltage (CV) charger. The constant charge current is programmable up to 2.0A with an external signal resistor. An internal trimmed current-sense circuit guarantees 10% accuracy, with no bulky external current-sense resistor. The constant voltage is either 4.1V or 4.2V. The charger always preconditions the battery with 1/10 of the programmed charge current at the beginning of a charge cycle, until it verifies that the battery can be fast-charged. A safety timer prevents over-charging a dead battery. The charging terminates as the charge current falls below the programmed minimum current during the CV mode. The charger automatically re-charges the battery when the battery voltage drops below a recharge threshold. A simple interface with an NTC thermistor avoids charging the battery outside a programmable temperature window. A thermalfoldback feature of the ISL6291 guarantees safe operation when the printed circuit board space is limited for thermal dissipation. The charger reduces the charge current automatically, as the internal temperature rises above a preset level, to prevent further temperature rise. When the wal...