BQ2057WSN (TEXAS INSTRUMENTS)

The BQ2057WSN is a Lithium-ion (Li-ion) and Lithium-polymer (Li-pol) linear charge-management Integrated Circuit which is designed for compact portable electronics. The BQ2057 continuously measures battery temperature using an external thermistor. For safety, the charge controller inhibits charge until the battery temperature is within user-defined thresholds. The charge controller 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), the charge controller precharges using a low current to condition the battery. The conditioning charge rate is approximately 10% 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 charge controller applies a constant current to the battery. An external sense-resistor sets the current.