AAT3663 Datasheet, PDF (13/22 Pages) Advanced Analogic Technologies – 1A Linear Li-Ion Battery Charger for Single and Dual Cell Applications

AAT3663
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
Application Information
Adapter or USB Power Input
Constant current charge levels up to 1A may be
programmed by the user when powered from a suf-
ficient input power source. The AAT3663 will oper-
ate over an input voltage range from 4.0V to 13.2V.
The low input voltage capability of the AAT3663
permits charging single cell Li-Ion/Poly batteries
from USB ports and lower voltage input power
sources. The high 13.2V input rating of this device
allows for the use of a wide range of input power
sources for both single and dual cell Li-Ion/Poly
applications.
Adapter Input Charge Inhibit and
Resume
The AAT3663 has an under-voltage lockout (UVLO)
and power on reset feature so that if the input sup-
ply to the IN pin drops below the UVLO threshold,
the charger will suspend charging and shut down.
When power is reapplied to the IN pin or the UVLO
condition recovers, the system charge control 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.
Battery Connection and Battery Voltage
Sensing
Battery Connection
A single or dual cell Li-Ion/Polymer battery should
be connected between the BAT pin and ground.
Battery Voltage Sensing
The BATS pin is provided to employ an accurate
voltage sensing capability to measure the positive
terminal voltage at the battery cell being charged.
This function reduces measured battery cell volt-
age error between the battery terminal and the
charge control IC. The AAT3663 charge control cir-
cuit will base charging mode states upon the volt-
age sensed at the BATS pin. The BATS pin must
be connected to the battery terminal for correct
operation. If the battery voltage sense function is
not needed, the BATS pin should be terminated
directly to the BAT pin. If there is concern of the
battery sense function inadvertently becoming an
open circuit, the BATS pin may be terminated to the
BAT pin using a 10kΩ resistor. Under normal oper-
ation, the connection to the battery terminal will be
close to 0Ω; if the BATS connection becomes an
open circuit, the 10kΩ resistor will provide feed-
back to the BATS pin from the BAT connection with
a voltage sensing accuracy loss of 1mV or less.
Enable (EN)
EN is a logic input (active high) to enable the
charger, this function is internally pulled down to
ground. When the device is initially enabled or if
the EN pin is cycled low and then 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 measured battery voltage on the BATS pin.
Programming Charge Current
The constant current mode charge level is user pro-
grammed with a set resistor (R_SET) connected
between the ISET pin and ground. The accuracy of
the constant charge current, as well as the precon-
ditioning trickle charge current, is dominated by the
tolerance of the set resistor used. For this reason, a
1% tolerance metal film resistor is recommended for
the set resistor function. The constant charge cur-
rent levels from 100mA to 1A may be set by select-
ing the appropriate resistor value from Table 1.
Constant Charging
Current (mA)
100
200
300
400
500
600
700
800
900
1000
Set Resistor
Value (kΩ)
17.8
8.87
5.9
4.42
3.57
2.94
2.55
2.21
1.96
1.78
Table 1: R_SET Values.
3663.2007.10.1.0
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