AAT3680
Lithium-Ion/Polymer
Linear Battery Charge Controller
Charge Status
Sleep / Charge Complete
Temp., OC, OV Fault
Battery Conditioning
Constant Current Mode
Constant Voltage Mode
Output Status
on/off
ON
LED Display
on/off
on/off
on/off
off / off / off / off
on / on / off / off
on / on / on / on
on / on / on / off
on / off / off / off
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
Figure 2: LED Display Output.
High-Speed Data Reporting
A high-speed data reporting application schematic
is shown in Figure 3. An optional system micro-
controller interface can be enabled by pulling up
the T2X pin to 4.5V to 5.5V during the power-up
sequence. The T2X pin should be pulled high with
the use of a 100kΩ resistor. If the input supply to
VP will not exceed 5.5V, then the T2X pin may be
tied directly to VP through a 100kΩ resistor. Since
this is a TTL-level circuit, it may not be pulled high-
er than 5.5V without risk of damage to the device.
When the high-speed data report feature is
enabled, the STAT output periods are sped up to
40µs, making the total status word 160µs in length
(see Figure 4).
An additional feature is the Output Status for
Battery Not Detected state. When the AAT3680
senses there is no battery connected to the BAT
pin, the STAT pin cycles for two periods, then
remains off for two periods.
When in high-speed data reporting, the AAT3680
will only trickle charge at the 2X trickle charge
level. This is because the TX2 pin is pulled high to
enable the high-speed data reporting.
A status display LED may not be connected to the
STAT pin when the high-speed data reporting is
being utilized. If both display modes are required,
the display LED must be switched out of the circuit
before the T2X pin is pulled high. Failing to do so
could cause problems with the high-speed switching
control circuits internal to the AAT3680.
R
SENSE
0.2
Q1
FZT788B
BATT+
VP
C2
10µF
VP
R1
2.5k
DRV
CSI
VP
C1
4.7µF
R2
100k
VSS
TX2
100k
BAT
TS
RT1
BATT-
AAT3680
TEMP
STAT
RT2
C3
0.1µF
Battery
Pack
STAT
Figure 3: High-Speed Data Reporting Application Schematic.
8
3680.2006.03.1.6
AAT [ ADVANCED ANALOG TECHNOLOGY, INC. ]
