AAT3687
Lithium-Ion/Polymer Battery Charger
System Operation Flow Chart
ADP
Voltage
ADP > VADPP
Yes
Yes
Yes
UVLO
VP > VUVLO
Output
ADPP
Switch
No
No
Sleep
Mode
No
Enable
Thermal
Loop
Power On
Reset
ADP
Loop
No
Device
Temperature
Monitor
Timing
Expire
Fault
Conditions Monitor
OV, OT
Yes
TJ > 110°C
Yes
No
Yes
Shut Down
Thermal Loop
Current
Reduction
Battery
Temperature Monitor
VTS1 < TS < VTS2
No
Battery
Temperature
Charge
Safety Timer
Yes
(AAT3687)
Yes
Set
Low Current
Conditioning
Recharge Test
VRCH > VBAT
Preconditioning Test
VMIN > VBAT
No
No
Yes
Yes
Current
Charging
Mode
Current Phase Test
VEOC > VBAT
No
Voltage
Charging
Mode
Voltage Phase Test
IBAT > ITERM
No
Charge
Completed
The constant current fast charge current for the
adapter input is set by the RSET resistor connected
between the ADPSET and ground. Refer to Table 1
for recommended RSET values for a desired con-
stant current charge level. The presence of voltage
on the adapter input is indicated by the ADPP# pin
function. This indicator pin uses an internal open
drain device that will pull the ADPP# pin low when
Application Information
Adapter Power Input
Constant current charge levels up to 1.5A may be
programmed by the user when powered from a suf-
ficient input power source. The AAT3687 will oper-
ate from the adapter input over a 4.0V to 5.5V
range.
3687.2006.10.1.7
11
AAT [ ADVANCED ANALOG TECHNOLOGY, INC. ]
