AAT3688
USB Port Lithium-Ion/Polymer Battery Charger
System Operation Flow Chart
Switch
On
Yes
UVLO
P > VUVLO
No
USB
Power
Sleep
Mode
V
0
1
USB Low
Current Loop
USB Detect
USBSEL= ?
Power On
Reset
USB High
Current Loop
Yes
Fault Conditions
Monitor
OV, OT
No
Shut Down
Mode
Battery
Temperature Monitor
No
Yes
Battery
Temp. Fault
VTS1 < TS < VTS2
USB Voltage
Regulation
Enable
No
No
Yes
Yes
Yes
Recharge Test
VRCH > VBAT
Low Current
Conditioning
Charge
USB Voltage Test
VUSB < 4.5V
Preconditioning Test
MIN > VBAT
V
Yes
No
USB
Loop Current
Reduction in USB
Charging Mode
Current
Charging
Mode
Current Phase Test
V
EOC > VBAT
No
Yes
Voltage
Charging
Mode
Voltage Phase Test
BAT > ITERM
I
No
Charge
Completed
12
3688.2006.10.1.5
AAT [ ADVANCED ANALOG TECHNOLOGY, INC. ]
