AAT3690 Datasheet, PDF (13/20 Pages) Advanced Analogic Technologies – 1.0A USB Port/Adapter Lithium-Ion/Polymer Battery Charger

AAT3690
1.0A USB Port/Adapter
Lithium-Ion/Polymer Battery Charger
I_CC
50
75
100
200
300
400
500
600
700
800
900
1000
ADP
R_SET (kΩ)
N/A
N/A
84.5
43.2
28.0
21.0
16.9
13.3
11.5
10.2
9.09
8.06
USB
R_SET (kΩ)
86.6
57.6
42.2
21.0
13.7
10.2
8.06
6.65
5.62
4.87
4.32
3.83
Table 1: Resistor Values.
The USB charge reduction system becomes active
when the voltage on the USB input falls below the
USB charge reduction threshold, which is typically
4.5V. The charge reduction system will reduce the
fast charge current level in a linear fashion until the
voltage sensed on the USB input recovers above
the charge reduction threshold voltage.
USB Input Charge Inhibit and Resume
The AAT3690 UVLO and power on reset feature
will function when the USB input pin voltage level
drops below the UVLO threshold. At this point, the
charger will suspend charging and shut down.
When power is re-applied to the USB pin or the
UVLO condition recovers, the system charge con-
trol will assess the state of charge on the battery
cell and will automatically resume charging in the
appropriate mode for the condition of the battery.
Enable / Disable
The AAT3690 provides an enable function to con-
trol the charger IC on and off. The enable (EN) pin
is active high and is internally pulled up to the high-
er voltage of ADP and USB supplies. When pulled
to a logic low level, the AAT3690 will be shut down
and forced into the sleep state. Charging will be
halted regardless of the battery voltage or charging
state. When the device is re-enabled, the charge
control circuit will automatically reset and resume
charging functions with the appropriate charging
mode based on the battery charge state and meas-
ured cell voltage.
Programming Charge Current
The fast charge constant current charge level for
both Adapter and USB input modes are pro-
grammed with set resistors placed between the
ADPSET and USBSET pins and ground. The accu-
racy of the fast charge is dominated by the toler-
ance of the set resistor used. For this reason, 1%
tolerance metal film resistors are recommended for
the set resistor function.
ADP fast charge constant current levels from 100mA
to 1.0A may be set by selecting the appropriate
resistor value from Table 1.
The USB charge may be set to any level between
50mA and 1.0A depending upon the system design
requirements for a given USB charge application.
Refer to Table 1 and Figure 2 for recommended
R_SETUSB values.
10000
1000
ADP
100
USB
10
1
10
100
R_SET (kΩ)
Figure 2: I_FASTCHARGE vs. R_SET.
3690.2007.01.1.2
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