AAT2552 Datasheet, PDF (15/33 Pages) Advanced Analogic Technologies – Total Power Solution for Portable Applications

AAT2552
Total Power Solution for Portable Applications
Functional Block Diagram
ADP
ISET
STAT
EN_BAT
ENB
MODE
INA
ENA
Current Compare
Constant Current
Reverse Blocking
Charge
Control
CV/Pre-Charge
UVLO
Charge Status
Voltage
Reference
Input
Err.
Amp
.
From
Charger Section
Over-Temperature
Protection
DH
Logic
DL
Fast Start
Control
Active Feedback
Control
+
Err.
Amp
-
Over-Current
Protection
Voltage
Reference
BAT
FBB
INB
LX
PGND
OUTA
FBA
Functional Description
The AAT2552 is a high performance power man-
agement IC comprised of a lithium-ion/polymer
battery charger, a step-down converter, and a lin-
ear regulator. The linear regulator is designed for
high-speed turn-on and fast transient response,
and good power supply ripple rejection. The step-
down converter operates in both fixed and variable
frequency modes for high efficiency performance.
The switching frequency is 1.5MHz, minimizing
the size of the inductor. In light load conditions,
the device enters power-saving mode; the switch-
ing frequency is reduced and the converter con-
sumes 45µA of current, making it ideal for battery-
operated applications.
2552.2007.04.1.0
AGND
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 charg-
er operates from the adapter/USB input voltage
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 out-
put pin is provided to indicate the battery 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 failure, the
device will automatically shut down, protecting the
charging device, control system, and the battery
under charge. Other features include an integrat-
ed reverse blocking diode and sense resistor.
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