AAT3683_08 Datasheet, PDF (14/23 Pages) Advanced Analogic Technologies – 1A Linear Li-Ion Battery Charger

BatteryManager^TM
10000
1000
100
10
1
10
100
R_SET (kΩ)
Figure 2: Constant Charging Current
vs. Set Resistor Values.
Programmable Charge
Termination Current
The charge termination current I_{CH_TERM} can be pro-
grammed by connecting a resistor from TERM to GND:
I_{CH_TERM}
=
15µA · R_TERM
2V
·
I_{CH_CC}
If the TERM pin is left open, the termination current will
set to 10% of the constant charging current as the
default value.
When the charge current drops to the defaulted 10% of
the programmed charge current level or programmed
terminated current in the constant voltage mode, the
device terminates charging and goes into a sleep state.
The charger will remain in this sleep state until the bat-
tery voltage decreases to a level below the battery
recharge voltage threshold (V_RCH).
Consuming very low current in sleep state, the AAT3683
minimizes battery drain when it is not charging. This
feature is particularly useful in applications where the
input supply level may fall below the battery charge or
under-voltage lockout level. In such cases where the
AAT3683 input voltage drops, the device will enter sleep
state and automatically resume charging once the input
supply has recovered from the fault condition.
PRODUCT DATASHEET
AAT3683
1A Linear Li-Ion Battery Charger
Charge Status Output
The AAT3683 provides battery charge status via a status
pin (AAT3683-4 provides battery charge status via two
status pins). This pin is internally connected to an
N-channel open-drain MOSFET, which can be used drive
an external LED. The status pin can indicate the follow-
ing conditions (AAT3683-2, AAT3683-3):
Event Description
No battery charging activity
Battery charging via adapter or USB port
Charging completed
STATUS
OFF
ON
OFF
Table 2: LED Status Indicator
(AAT3683-2/AAT3683-3).
The status pins can indicate the following conditions
(AAT3683-4):
Event Description
Charge enabled without battery
Battery charging
Charge completed
Fault
STAT1
FLASH¹
ON
OFF
OFF
STAT2
FLASH¹
OFF
ON
OFF
Table 3: LEDs Status Indicator
(AAT3683-4).
The LED should be biased with as little current as neces-
sary to create reasonable illumination; therefore, a bal-
last resistor should be placed between the LED cathode
and the STAT pin. LED current consumption will add to
the overall thermal power budget for the device pack-
age, hence it is good to keep the LED drive current to a
minimum. 2mA should be sufficient to drive most low-
cost green or red LEDs. It is not recommended to exceed
8mA for driving an individual status LED.
1. Flashing rate depends on output capacitance.
14
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