C0098C0113C0050C0052C0057C0048C0049

SLUS527 – DECEMBER 2002
C0083C0073C0078C0071C0076C0069C0262C0067C0069C0076C0076 C0076C0073C0262C0073C0079C0078 C0065C0078C0068 C0076C0073C0262C0080C0079C0076 C0067C0072C0065C0082C0071C0069 C0077C0065C0078C0065C0071C0069C0077C0069C0078C0084 C0073C0067
C0070C0079C0082 C0079C0070C0070C0076C0073C0078C0069 C0065C0080C0080C0076C0073C0067C0065C0084C0073C0079C0078C0083
1
www.ti.com
FEATURES
C0068 Designed for Off-Line Charger Design for
Single-Cell Li-Ion Packs
C0068 Provides Control Feedback to a Primary-Side
Controller
C0068 Robust Battery Insertion and Removal
Detection
C0068 Charge Current and Voltage Regulation
Feedback to Primary-Side for High-Accuracy
Charging
C0068 Charge Termination by Minimum Current and
Time
C0068 Pre-Charge Conditioning Regulator with
Safety Timer
C0068 Charge Status Outputs for LED or Host
Processor Interface Indicates Charge-
in-Progress, Charge Completion, and Fault
Conditions
C0068 Temperature Monitoring Before and During
Charge
C0068 Short-Circuit Protection
C0068 Small, 14-Pin TSSOP Package
APPLICATIONS
C0068 Cradle Chargers for Digital Cameras
C0068 Desktop Chargers
C0068 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.
C0080C0082C0079C0068C0085C0067C0084C0073C0079C0078 C0068C0065C0084C0065 C0105C0110C0102C0111C0114C0109C0097C0116C0105C0111C0110 C0105C0115 C0099C0117C0114C0114C0101C0110C0116 C0097C0115 C0111C0102 C0112C0117C0098C0108C0105C0099C0097C0116C0105C0111C0110 C0100C0097C0116C0101C0046
C0080C0114C0111C0100C0117C0099C0116C0115 C0099C0111C0110C0102C0111C0114C0109 C0116C0111 C0115C0112C0101C0099C0105C0102C0105C0099C0097C0116C0105C0111C0110C0115 C0112C0101C0114 C0116C0104C0101 C0116C0101C0114C0109C0115 C0111C0102 C0084C0101C0120C0097C0115 C0073C0110C0115C0116C0114C0117C0109C0101C0110C0116C0115
C0115C0116C0097C0110C0100C0097C0114C0100 C0119C0097C0114C0114C0097C0110C0116C0121C0046 C0080C0114C0111C0100C0117C0099C0116C0105C0111C0110 C0112C0114C0111C0099C0101C0115C0115C0105C0110C0103 C0100C0111C0101C0115 C0110C0111C0116 C0110C0101C0099C0101C0115C0115C0097C0114C0105C0108C0121 C0105C0110C0099C0108C0117C0100C0101
C0116C0101C0115C0116C0105C0110C0103 C0111C0102 C0097C0108C0108 C0112C0097C0114C0097C0109C0101C0116C0101C0114C0115C0046
Copyright  2002, Texas Instruments Incorporated