AAT2557
500mA Battery Charger and 300mA
LDO Regulator for Portable Systems
Functional Block Diagram
Reverse Blocking
BAT
ADP
-
-
+
Constant
Current
Charge
Control
ISET
VREF
STAT
Over-
Temperature
Protection
UVLO
EN_BAT
BYP
INLDO
Err.
Amp.
VREF
Over-
Current
Protection
OUTLDO
ENLDO
GND
charger operates from the adapter/USB input volt-
age range from 4V to 6.5V. The adapter/USB
charging current level can be programmed up to
500mA for rapid charging applications. A status
monitor output pin is provided to indicate the bat-
tery charge state by directly driving one external
LED. Internal device temperature and charging
state are fully monitored for fault conditions. In the
event of an over-voltage or over-temperature fail-
ure, the device will automatically shut down, pro-
tecting the charging device, control system, and
the battery under charge. Other features include
an integrated reverse blocking diode and sense
resistor.
Functional Description
The AAT2557 is a high performance power man-
agement IC comprised of a lithium-ion/polymer
battery charger and a linear regulator. The linear
regulator is designed for high-speed turn-on, fast
transient response, good power supply ripple
rejection, and low noise.
Battery Charger
The battery charger is designed for single-cell lithi-
um-ion/polymer batteries using a constant current
and constant voltage algorithm. The battery
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2557.2007.06.1.0
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
