AAT3690 Datasheet, PDF (9/20 Pages) Advanced Analogic Technologies – 1.0A USB Port/Adapter Lithium-Ion/Polymer Battery Charger

AAT3690
1.0A USB Port/Adapter
Lithium-Ion/Polymer Battery Charger
Functional Block Diagram
USB
USBSET
ADPSET
ADP
STAT1
STAT2
EN
Reverse Blocking
Charge
Reduction
Loop
Current
Compare
Constant
Current
Current
Compare
Charge
Control
CV
UVLO
Over-
Temperature
Protect
BAT
Voltage
Sense
Charge
Status
Reverse Blocking
80μA
Window
Comparator
IC enable
Watchdog
Timer
TS
CT
GND
Functional Description
The AAT3690 is a highly integrated single-cell lithi-
um-ion/polymer battery charger IC designed to
operate with USB port and AC adapter inputs, while
requiring a minimum number of external compo-
nents. The AAT3690 precisely regulates battery
charge voltage and current for 4.2V lithium-ion/poly-
mer battery cells.
The adapter charge input constant current level can
be programmed up to 1.0A for rapid charging appli-
cations. In the absence of a high-current adapter
input source, the AAT3690 can be powered from a
USB port V_BUS supply. The USB constant charge
current can be externally programmed for maximum
constant current charge levels up to 1A.
The USB mode has an automatic Charge
Reduction Loop control to allow users to charge
the battery with limited available current from a
USB port while maintaining the regulated port volt-
3690.2007.01.1.2
age. This system assures the battery charge func-
tion will not overload a USB port while charging if
other system demands also share power with the
respective port supply. The USB charge function is
automatically disabled when an adapter input
power source greater than 4.4V is present.
Status monitor output pins are provided to indicate
the battery charge status by directly driving two
external LEDs.
Battery temperature and charge state are fully mon-
itored for fault conditions. In the event of an over-
voltage or over-temperature condition, the device
will automatically shut down, thus protecting the
charging device, control system, and the battery
under charge. In addition to internal charge con-
troller thermal protection, the AAT3690 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.
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