AAT3681_08 Datasheet, PDF (8/15 Pages) Advanced Analogic Technologies – USB Port or AC Adapter Lithium-Ion/Polymer Battery Charger

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PRODUCT DATASHEET
AAT3681
USB Port or AC Adapter Lithium-Ion/Polymer Battery Charger
Functional Block Diagram
ADP
Reverse Blocking
BAT
Current
Compare
CV/
Precharge
ISET
Constant
Current
STAT
EN
Charge
Status
Charge
Control
UVLO
Over-
Temperature
Protection
GND
Functional Description
The AAT3681 is a high performance battery charger
designed to charge single cell lithium-ion/polymer bat-
teries with up to 300mA of current from an external
power source. It is a stand-alone charging solution, with
just one external component required for complete func-
tionality. The AAT3681 precisely regulates battery charge
voltage and current for 4.2V lithium-ion/polymer battery
cells.
The adapter/USB charge input constant current level can
be programmed up to 300mA for rapid charging applica-
tions. The AAT3681 is rated for operation from -40°C to
+85°C. In the event of operating ambient temperatures
exceeding the power dissipation abilities of the device
package for a given constant current charge level, the
charge control will enter into thermal limit.
A status monitor output pin is provided to indicate the
battery charge state by directly driving one external
LED.
Device junction temperature and charge state are fully
monitored for fault conditions. In the event of an over-
voltage or over-temperature failure, the device will auto-
matically shut down, protecting the charging device,
control system, and the battery under charge.
Charging Operation
The AAT3681 has four basic modes for the battery
charge cycle: pre-conditioning/trickle charge; constant
current/fast charge; constant voltage; and end of charge
(see Figure 1). (AAT3681-1 does not have trickle
charge.)
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3681.2007.12.1.5