Texas Instruments BQ2057TSN

Low Dropout Linear 2-cell Li-Ion Charge Controller with AutoCompTM, 8.2V 8-SOIC -20 to 70
Linear Charge Management Li-Ion/Li-Pol 2000mA 8.2V 8-Pin SOIC Tube
Battery Management IC; Battery Management Function:Charger, Protector, Status Monitor; Battery Type:Li-Ion, Li Polymer; Input Voltage Primary Max:18.3V; Charge Current Max:2A; Output Voltage Max:8.2V; No. of Series Cells:2 ;RoHS Compliant: Yes
The BENCHMARQ bq2057 series advanced Lithium-Ion (Li-Ion) and Lithium-Polymer (Li-Pol) linear charge-management ICs are designed for cost-sensitive and compact portable electronics. They combine high-accuracy current and voltage regulation,battery conditioning, temperature monitoring, charge termination, charge-status indication, and AutoCompcharge-rate compensation in a single 8-pin IC. MSOP, TS SOP, and SOIC package options are offered to fit awide range of end applications. The bq2057 continuously measures battery temperature using an external thermistor. For safety, the bq2057 inhibits charge until the battery temperatureis within user-defined thresholds. The bq2057 then charges the battery in three phases: conditioning,constant current, and constant voltage. If the battery voltage is below the low-voltage threshold, V (min), thebq2057 precharges using a low current to condition the battery. The conditioning charge rate is approximately10% of the regulation current. The conditioning current also minimizes heat dissipation in the external pass-element during the initial stage of the charge. After conditioning, the bq2057 applies a constant current tothe battery. An external sense-resistor sets the current. The sense-resistor can be on either the high or low side of the battery without additional components. The constant-current phase continues until the battery reaches the charge-regulation voltage.