AAT3687_08 Datasheet, PDF (9/20 Pages) Advanced Analogic Technologies – Lithium-Ion/Polymer Battery Charger

BatteryManager^TM
Functional Block Diagram
PRODUCT DATASHEET
AAT3687
Lithium-Ion/Polymer Battery Charger
ADPSET
ADP
ADPP#
STAT1
STAT2
DATA
EN
4.2V
Constant
Current
Current
Compare
Charge
Control
CV/
Precharge¹
UVLO
Over-
Temperature
Protection
BAT
Voltage
Sense
Reverse Blocking
Charge
Status
Serial
Data
IC enable
Window
Comparator
Watchdog
Timer
80µA
TS
CT
GND
Functional Description
The AAT3687 is a highly integrated single-cell lithium-
ion/polymer battery charger IC designed to operate with
standard AC adapter input sources, while requiring a
minimum number of external components. The AAT3687
precisely regulates battery charge voltage and current
for 4.2V lithium-ion/polymer battery cells.
The adapter charge input constant current level can be
programmed up to 1.5A for rapid charging applications.
The AAT3687 is rated for operation from -40°C to +85°C.
In the event of operating ambient temperatures exceed-
ing the power dissipation abilities of the device package
for a given constant current charge level, the charge
control will enter into thermal regulation. When the sys-
tem thermal regulation becomes active, the programmed
constant current charge amplitude will be automatically
reduced to a safe level for the current operating condi-
tion. Should the ambient operating temperature drop
below the thermal loop threshold, the system will auto-
matically resume charging at the full programmed con-
stant current level. This intelligent thermal management
system permits the AAT3687 to operate and safely
charge a battery cell over a wide range of ambient condi-
tions while maximizing the greatest possible charge cur-
rent for the given set of conditions.
Status monitor output pins are provided to indicate the
battery charge state by directly driving two external LEDs.
A serial interface output is also available to report any one
of 12 distinct charge states to the system microcontroller.
Battery temperature and charge state are fully monitored
for fault conditions. In the event of an over-voltage or
over-temperature failure, the device will automatically
shut down, thus protecting the charging device, control
system, and the battery under charge. In addition to
internal charge controller thermal protection, the AAT3687
also provides a temperature sense feedback function (TS
pin) from the battery to shut down the device in the
event the battery exceeds its own thermal limit during
charging. All fault events are reported to the user either
by the simple status LEDs or via the DATA pin function.
1. Precharge applies to AAT3687 and AAT3687-1 only.
3687.2008.04.1.12
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