Features

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

Pre-charge 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

General Description

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 qualifiction, 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.