AAT3680 Advanced Analogic Technologies, AAT3680 Datasheet - Page 6

• Manufacturer Part Number: AAT3680
• Description: Lithium-Ion Linear Battery Charge Controller
• Manufacturer: Advanced Analogic Technologies

Constant Voltage Charging
When the battery's voltage reaches V
constant-current mode, the AAT3680 transitions to
constant-voltage mode. The regulation voltage is
factory programmed: 4.1V and 4.2V (or 8.2V and
8.4V for two-cell applications) are available to sup-
port different anode materials in Lithium Ion cells.
In constant-voltage operation, the AAT3680 moni-
tors the cell voltage and terminates the charging
cycle when the voltage across R
approximately 10mV.
6
Temperature
Temperature
Fault
Fault
SENSE
Figure 1: AAT3680 Operational Flow Chart
< V
decreases to
RCH
No
CH
Lithium-Ion Linear Battery Charge Controller
during
Preconditioning Test
Current Phase Test
Temperature Test
Charge Complete
Power On Reset
Charge Complete
V
Phase Test
Power On Reset
R
Latch Off
V
V
V
TS > V
TS < V
MIN
Voltage
SENSE
CH
TERM
P
UVLO
Latch Off
> V
> V
> V
UVLO
TS1
TS2
No
No
BAT
No
Yes
BAT
< I
Yes
BAT
Charge Cycle Termination, Recharge
Sequence
After the charge cycle is complete, the AAT3680
latches off the pass device and automatically enters
power-saving sleep mode. Either of two possible
conditions will bring the IC out of sleep mode: the
battery voltage at the BAT pin drops below V
(recharge threshold voltage) or the AAT3680 is reset
by cycling the input supply through the power-on
sequence. Falling below V
is time to initiate a new charge cycle.
No
Yes
Yes
Yes
(Trickle Charge)
Low Current
Conditioning
Shut Down
Conditioning
Low Current
Charging
Charging
Charge
Shut Down
Current
Voltage
Charging
Charging
Mode
Mode
Mode
Voltage
Charge
Current
Mode
Mode
Mode
RCH
signals the IC that it
AAT3680
3680.2003.4.0.91
RCH