C0098C0113C0050C0052C0050C0048C0048C0044 C0098C0113C0050C0052C0050C0048C0049C0044 C0098C0113C0050C0052C0050C0048C0050
C0098C0113C0050C0052C0050C0048C0051C0044 C0098C0113C0050C0052C0050C0048C0052C0044 C0098C0113C0050C0052C0050C0048C0053
SLUS501A – OCTOBER 2001
C0083C0073C0078C0071C0076C0069C0262C0067C0072C0073C0080 C0076C0073C0262C0073C0079C0078 C0065C0078C0068 C0076C0073C0262C0080C0079C0076 C0067C0072C0065C0082C0071C0069 C0077C0065C0078C0065C0071C0069C0077C0069C0078C0084 C0073C0067
C0070C0079C0082 C0067C0085C0082C0082C0069C0078C0084C0262C0076C0073C0077C0073C0084C0069C0068 C0065C0080C0080C0076C0073C0067C0065C0084C0073C0079C0078C0083
1
www.ti.com
FEATURES
C0068 Designed Specifically to Work With
Current-Limited Wall Supplies
C0068 Ideal for Low Dropout Charger Design for
Single-Cell Li-Ion Packs With Coke or
Graphite Anodes
C0068 Integrated PowerFET for 500 mA
C0068 Integrated Voltage Regulation With 0.5%
Accuracy
C0068 Battery Insertion and Removal Detection
C0068 Charge Termination by Minimum Current and
Time
C0068 Pre-Charge Conditioning With Safety Timer
C0068 Sleep Mode for Low-Power Consumption
C0068 Charge Status Output for LED or Host
Processor Interface Indicates
Charge-in-Progress, Charge Completion, and
Fault Conditions
C0068 Optional Temperature Monitoring Before and
During Charge
C0068 Small, 8-Pin Power-Pad MSOP Package
TYPICAL APPLICATION

DESCRIPTION
The bq2420x series are simple Li-Ion linear
charge management devices targeted at low-cost
and space limited charger applications. The
bq2420x series offer integrated powerFET,
high-accuracy voltage regulation, temperature
monitoring, charge status, and charge
termination, in a single monolithic device.
The bq2420x is designed to work with a
current-limited wall-mount transformer and
therefore does not provide any current regulation.
However, these devices offer a fixed internal
current limit to prevent damage to the internal
powerFET. A time-limited pre-conditioning phase
is provided to condition deeply discharged cells.
Once the battery reaches the charge voltage, the
high accuracy voltage regulation loop takes over
and completes the charge cycle. Charge is
terminated based on minimum current. An internal
charge timer provides a backup safety for charge
termination.
Other standard features include an automatic
sleep mode activated when V
CC
falls below the
battery voltage and a recharge feature activated
when the battery voltage falls below the V
RCH
threshold.
In addition to the standard features, the core
product provides two additional enhancements:
temperature monitoring and status display. The
temperature-sense circuit continuously measures
battery temperature using an external thermistor
and inhibits charge until the battery temperature is
within the user–defined thresholds. The STAT pin
indicates three conditions of operation of the
charger. These conditions are charge-
in-progress, charge complete, and fault. This
output can be used to drive an LED or an interface
to a microcontroller.
Copyright  2001, Texas Instruments Incorporated
1
4
2
8IN
VCC
VSS
OUT
7BAT
6CE
5N/C
C1
bq24202DGN
3STAT
DC+
DC–
R1
C1
+
BATTERY PACK
UDG–01111
C0080C0082C0079C0068C0085C0067C0084C0073C0079C0078 C0068C0065C0084C0065 C0105C0110C0102C0111C0114C0109C0097C0116C0105C0111C0110 C0105C0115 C0099C0117C0114C0114C0101C0110C0116 C0097C0115 C0111C0102 C0112C0117C0098C0108C0105C0099C0097C0116C0105C0111C0110 C0100C0097C0116C0101C0046
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C0115C0116C0097C0110C0100C0097C0114C0100 C0119C0097C0114C0114C0097C0110C0116C0121C0046 C0080C0114C0111C0100C0117C0099C0116C0105C0111C0110 C0112C0114C0111C0099C0101C0115C0115C0105C0110C0103 C0100C0111C0101C0115 C0110C0111C0116 C0110C0101C0099C0101C0115C0115C0097C0114C0105C0108C0121 C0105C0110C0099C0108C0117C0100C0101
C0116C0101C0115C0116C0105C0110C0103 C0111C0102 C0097C0108C0108 C0112C0097C0114C0097C0109C0101C0116C0101C0114C0115C0046