AAT3698 Datasheet, PDF (11/21 Pages) Skyworks Solutions Inc. – 1.6A Linear Li-Ion Battery Charger in a 3x3 TDFN Package

DATA SHEET
AAT3698
1.6A Linear Li-Ion Battery Charger in a 3x3 TDFN Package
Functional Block Diagram
OVP
Switch
IN
OVP
Control
INCHR
TERM
ISET
EN
200kΩ
POK
POK
Current
Sense
UVLO
OVP Flag
Reverse
Blocking
5V LDO
1600kΩ
Charge
Control
BATS
BAT
POK
200kΩ
+
IN
-
BAT
GND
BAT
LDOOUT
NOBAT
ABO
ABI
STAT
Functional Description
The AAT3698-1/-2 is a high performance battery charger
IC which is designed to charge single-cell Lithium-Ion or
Polymer batteries with up to 1.6A of current from an
external power source. It is a stand-alone charging solu-
tion requiring minimum input components. The AAT3698-
1/-2 also includes a fast turn-off over-voltage protection
(OVP) circuit with +28V which consists of a low-resis-
tance MOSFET in series with the charge control circuit.
The AAT3698-1/-2 also features under-voltage lockout
protection, power OK, charge status monitoring, and a
5.0V LDO with 50mA output through the OVP switch.
Battery Charging Profile
Figure 1 illustrates the entire battery charging operation
profile, which consists of three (AAT3698-2) or four
(AAT3698-1) phases:
1. Preconditioning (Trickle) Charge
2. Constant Current Charge (CC)
3. Constant Voltage Charge (CV)
4. Automatic Recharge (AAT3698-1 only)
Preconditioning Charge
Battery charging commences only after the AAT3698-1/-
2 checks several conditions in order to maintain a safe
charging environment. The input supply must be above
the minimum operating voltage (V_MIN) or under-voltage
lockout threshold (V_UVLO) and the enable pin must be low
for the charging sequence to begin. When these condi-
tions have been met and a battery is connected to the
BAT pin, the AAT3698-1/-2 checks the state of the bat-
tery and determines which charging mode to apply. If
the battery voltage is below the preconditioning voltage
threshold (V_MIN), then the AAT3698-1/-2 begins precon-
ditioning the cell (trickle charging) by charging at 10%
of the programmed constant current. For example, if the
programmed fast charge current is 1000mA, then the
preconditioning (trickle) charge current is 100mA.
Battery cell preconditioning is a safety precaution for
deeply discharged cells and will also reduce the power
dissipation in the internal series pass transistor when the
voltage across the device is at greatest potential.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
201902B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 27, 2012
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