The bq2954 Li-Ion Charge-Management IC uses a flexible pulse-width modulation regulator to control voltage and current during charging. The regulator frequency is set by an external capacitor for design flexibility. The switch-mode design minimizes power dissipation.

For safety, the bq2954 inhibits fast charging until the battery voltage and temperature are within configured limits. If the battery voltage is less than the low-voltage threshold, the bq2954 provides low-current conditioning of the battery.

For charge qualification, the bq2954 uses an external thermistor to measure battery temperature. Charging begins when power is applied or the battery is inserted

The bq2954 charges a battery in two phases. First a constant-current phase replenishes approximately 70% of battery capacity. Then a voltage- regulation phase completes the battery charge.

The bq2954 provides status indications of all charger states and faults for accurate determination of the battery and charge-system conditions.

• Safe charge of Li-Ion battery packs
• Pulse-width modulation control for current and voltage regulation
• Programmable high-side/low-side current-sense
• Fast charge terminated by selectable minimum current; safety backup termination at maximum time
• Precharge qualification detects shorted or damaged cells and conditions battery
• Charging continuously qualified by temperature and voltage limits
• Direct LED control outputs to display charge status and fault conditions