Features

➤ Safe charge of Lithium Ion battery

packs

➤ Voltage-regulated currentlimited

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 switchmode

power conversion

➤ Direct LED control outputs display

charge status and fault conditions

General Description

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 outside

the preconfigured limits.

The bq2054 provides status indications

of all charger states and faults

for accurate determination of the

battery and charge system conditions.