BQ24901 Datasheet, PDF (1/18 Pages) Texas Instruments – SINGLE-CELL LI-ION AND LI-POL CHARGE MANAGEMENT IC FOR OFFLINE APPLICATIONS

bq24901
SLUS527 – DECEMBER 2002
SINGLEĆCELL LIĆION AND LIĆPOL CHARGE MANAGEMENT IC
FOR OFFLINE APPLICATIONS
FEATURES
D Designed for Off-Line Charger Design for
Single-Cell Li-Ion Packs
D Provides Control Feedback to a Primary-Side
Controller
D Robust Battery Insertion and Removal
Detection
D Charge Current and Voltage Regulation
Feedback to Primary-Side for High-Accuracy
Charging
D Charge Termination by Minimum Current and
Time
D Pre-Charge Conditioning Regulator with
Safety Timer
D Charge Status Outputs for LED or Host
Processor Interface Indicates Charge-
in-Progress, Charge Completion, and Fault
Conditions
D Temperature Monitoring Before and During
Charge
D Short-Circuit Protection
D Small, 14-Pin TSSOP Package
APPLICATIONS
D Cradle Chargers for Digital Cameras
D Desktop Chargers
D Handheld Devices
DESCRIPTION
The bq24901 Li-Ion charge management devices
are designed specifically for off-line charger
applications. The bq24901 resides on the
secondary-side of the transformer and provides
the control feedback to a variety of primary side
controllers. The bq24901 offers current or voltage
regulation feedback, temperature monitoring,
charge status, and adjustable charge termination,
in a single monolithic device. During
battery-absent or charge-complete conditions,
the bq24901 continuously regulates the
secondary-side voltage, used as V_CC supply to
the device.
The bq24901 features a time-limited precon–
ditioning phase to condition deeply discharged
cells. The pre-conditioning phase is achieved by
linear regulation in the secondary side. Following
preconditioning, the bq24901 regulates the
charge current to the value set by the external
current sense resistor. Once the battery reaches
the charge voltage, the voltage regulation loop
takes over and completes the charge cycle. The
accuracy of the voltage regulation is better than
±30mV. Charge is terminated based on minimum
current. The minimum current level is set through
TADJ pin. An internal five-hour charge timer
provides a backup for charge termination.
The bq24901 is designed to reliably detect battery
insertion and removal conditions, including packs
with open protectors. Other standard features
include a recharge feature activated when the
battery voltage falls below the V_RCH threshold.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
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Copyright  2002, Texas Instruments Incorporated
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