AAT3681AIJS-4.2-2-T1 ANALOGICTECH [Advanced Analogic Technologies], AAT3681AIJS-4.2-2-T1 Datasheet - Page 8

• Manufacturer Part Number: AAT3681AIJS-4.2-2-T1
• Description: 500mA USB Port or AC Adapter Lithium-Ion/Polymer Battery Charger
• Manufacturer: ANALOGICTECH [Advanced Analogic Technologies]

Functional Block Diagram
Functional Description
The AAT3681A is a high performance battery
charger designed to charge single cell lithium-
ion/polymer batteries with up to 500mA of current
from an external power source. It is a stand-alone
charging solution, with just one external compo-
nent required for complete functionality. The
AAT3681A precisely regulates battery charge volt-
age and current for 4.2V lithium-ion/polymer bat-
tery cells.
The adapter/USB charge input constant current
level can be programmed up to 500mA for rapid
charging applications. The AAT3681A is rated for
operation from -40°C to +85°C. In the event of oper-
ating 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.
8
STAT
ISET
ADP
EN
Charge
Status
Compare
Constant
Current
Current
Lithium-Ion/Polymer Battery Charger
Charge
Control
Reverse Blocking
A status monitor output pin is provided to indicate
the battery charge state by directly driving one
external LED.
Device junction temperature and charge 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.
Charging Operation
The AAT3681A has four basic modes for the bat-
tery charge cycle: pre-conditioning/trickle charge;
constant current/fast charge; constant voltage; and
end of charge. (See Figure 1.) (AAT3681A-1 does
not have trickle charge.)
500mA USB Port or AC Adapter
Temperature
Precharge
Protection
UVLO
Over-
CV/
AAT3681A
GND
BAT
3681A.2007.10.1.2