AAT3682
Lithium-Ion/Polymer Linear Battery Charger
Functional Block Diagram
VP
BAT
GATE
2X Trickle
Charge
Control
Loop Select
MUX
Driver
T2X
DRV
CSI
Current Loop
Error Amp
Microcontroller
Status Generator
STAT
VREF
Charge Status
MUX
Voltage Loop
Error Amp
Logic Control
BSENSE
LED Signal
Generator
Voltage
Comparator
Microcontroller
Read Enable
T2X
VSS
Temperature
Sense
Comparator
TS
Over-Current /
Power-On
Reset
Under-Voltage
Short-Circuit
Lock Out
VCC
Protection
Cell Preconditioning
Before the start of charging, the AAT3682 checks
Functional Description
The AAT3682 is a linear charger designed for single-
cell lithium-ion/polymer batteries. It is a full-featured
battery management system IC with multiple levels
of power savings, system communication, and pro-
tection integrated inside. Refer to the block diagram
above and the flow chart and typical charge profile
graph (Figures 1 and 2) in this section.
several conditions in order to maintain a safe charg-
ing environment. The input supply must be above
the minimum operating voltage, or under-voltage
lockout threshold (VUVLO), for the charging
sequence to begin. Also, the cell temperature, as
reported by a thermistor connected to the TS pin,
must be within the proper window for safe charging.
8
3682.2006.12.1.3
AAT [ ADVANCED ANALOG TECHNOLOGY, INC. ]
