AAT3663_08 Datasheet, PDF (12/23 Pages) Advanced Analogic Technologies – 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications

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PRODUCT DATASHEET
AAT3663
1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications
Functional Block Diagram
Reverse Blocking
IN
Current
Compare
CV/
Precharge
ISET
TERM
Constant
Current
Charge
Control
ADPP#
Power
Detection
EN
75μA
AAT3663-2 Only
TS
Window Comparator
GND
UVLO
Over-Temp Thermal
Protect
Loop
Charge
Status
Watchdog
Timer
BAT
BATS
STAT 1
STAT 2
CT
Functional Description
The AAT3663 is a high performance battery charger
designed to charge single/dual cell Lithium-Ion or
Lithium-Polymer batteries with up to 1000mA of current
from an external power source. It is a highly integrated
stand-alone charging solution, with the least external
components required for complete functionality.
The AAT3663 precisely regulates end of charge battery
voltage and current for single cell 4.2V and dual cell 8.4V
lithium-ion/polymer battery with a programmable con-
stant current range from 100mA to 1A for fast charging
applications. The system has a default charge termina-
tion current set to 10 percent of the programmed fast
charge constant. The charge termination current may
also be user programmed by an external resistor.
During battery charging, the device temperature will rise.
In some cases with adapter (ADP) charging, the power
dissipation in the charge regulation pass device may
cause the junction temperature to rise and approach the
internal thermal shutdown threshold. Excessive power
dissipation is caused by the high input adapter voltage
versus the low output battery cell voltage difference at a
given constant charge current. In the event of an internal
over-temperature condition caused by excessive ambient
operating temperature or excessive power dissipation
conditions, the AAT3663 enables a digitally controlled
thermal loop system that will reduce the charging current
to prevent thermal shutdown. The digital thermal loop
will maintain the maximum possible battery charging
current for a given set of input to output power dissipa-
tion and ambient temperature conditions.
The digital thermal loop control is dynamic in the sense
that it will continue to adjust the battery charging current
as operating conditions change. The digital thermal loop
will reset and resume normal operation when the power
dissipation or over-temperature conditions are removed.
In the event of an over-voltage, over-current or over-
temperature false condition beyond the limits of the
digital thermal loop system, the device will automati-
cally shut down, thus protecting the charging device,
control system, and the battery under charge.
AAT3663 provides two status monitor pins, STAT1 and
STAT2. These pins are open drain MOSFET switches
intended to directly drive external LEDs to indicate the
battery charging state. A third status pin is prided to
indicate the presence of power on the input supply pin.
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3663.2008.01.1.2