The bq2054 Lithium Ion Fast-Charge IC is designed to optimize charging of lithium ion (Li-Ion) chemistry batteries. A flexible pulse-width modulation regulator allows the bq2054 to control voltage and current during charging. The regulator frequency is set by an external capacitor for design flexibility. The switch-mode design keeps power dissipation to a minimum.

The bq2054 measures battery temperature using an external thermistor for charge qualification. Charging begins when power is applied or on battery insertion.

For safety, the bq2054 inhibits charging until the battery voltage and temperature are within configured limits. If the battery voltage is less than the low-voltage threshold, the bq2054 provides low-current conditioning of the battery.

A constant current-charging phase replenishes up to 70% of the charge capacity, and a voltage-regulated phase returns the battery to full. The charge cycle terminates when the charging current falls below a user-selectable current limit. For safety, charging terminates after maximum time and is suspended if the temperature is out-side the preconfigured limits.

The bq2054 provides status indications of all charger states and faults for accurate determination of the battery and charge system conditions.

• Safe charge of Lithium Ion battery packs
• Voltage-regulated current-limited charging
• Fast charge terminated by selectable minimum current; safety backup termination on maximum time
• Charging continuously qualified by temperature and voltage limits
• Pulse-width modulation control ideal for high-efficiency switch-mode power conversion
• Direct LED control outputs display charge status and fault conditions