BQ2057SN (TEXAS INSTRUMENTS)

The BQ2057SN is an advance linear charge management Integrated Circuit for single and two cell lithium ion and lithium polymer. This IC combines high-accuracy current and voltage regulation, battery conditioning, temperature monitoring, charge termination, charge-status indication and AutoComp charge-rate. The BQ2057 continuously measures battery temperature using an external thermistor. For safety, the IC inhibits charge until the battery temperature is within user-defined thresholds. The IC 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 IC pre-charges 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 IC applies a constant current to the battery.