AAT3684 Datasheet, PDF (8/17 Pages) Advanced Analogic Technologies – 500mA USB Port or AC Adapter Lithium-Ion/Polymer Battery Charger

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PRODUCT DATASHEET
AAT3684
500mA 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 AAT3684 is a high performance battery charger
designed to charge single cell lithium-ion/polymer bat-
teries with up to 500mA 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 AAT3684 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 500mA for rapid charging applica-
tions. The AAT3684 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.
Battery temperature and charge state are fully moni-
tored for fault conditions. In the event of an over-voltage
or over-temperature failure, the device will automati-
cally shut down, protecting the charging device, control
system, and the battery under charge.
Charging Operation
The AAT3684 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.) (AAT3684-1 does not have trick-
le charge.)
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