AAT3692 Datasheet, PDF (10/19 Pages) Skyworks Solutions Inc. – Dual Input 1.6A Linear Charger with 28V OVP in a 3x4 TDFN Package

DATA SHEET
AAT3692
Dual Input 1.6A Linear Charger with 28V OVP in a 3x4 TDFN Package
Functional Block Diagram
USB
USBCH
USBSET
EN
TERM
ADPSET
POK
ADPCH
OVP Switch
OVP Sense
and Control
Current
Sense
OVP Sense
and Control
Power
Detection
Current
Sense
Reverse Blocking
Charge
Control
CV/ pre -
charge
UVLO
Over-Temp.
Protection
Charge
Status
BAT
NOBAT
STAT
ADP
Reverse Blocking
GND
Functional Description
The AAT3692 is a high performance battery charger
designed to charge single cell lithium-ion or polymer bat-
teries with up to 1600mA charging current from an
adapter (ADP) power source, or with up to 500mA charg-
ing current from an USB power source. The AAT3692 is
a stand-alone charging solution, with just a few external
components required for complete functionality. Both
input paths include a fast turn-off over-voltage protec-
tion (OVP) circuit with voltage up to +28V and an under-
voltage lockout level of 3.0V.
The AAT3692 automatically selects the charging source
from USB or ADP according to ADP and USB voltage. The
ADP path is always the high priority charging path when
ADP voltage is higher than 4.5V. The charging current is
determined by the selected charging path and its exter-
nal set resistor (R_SET).
USB charging uses an automatic charge reduction loop
control to allow battery charging with limited available
current from a USB port while maintaining the regulated
port voltage. This system assures that the battery
charge function will not overload a USB port while charg-
ing if other system demands also share power with the
respective port supply.
During adapter charging, high set charging current or
high ambient operating temperature may cause the
AAT3692 junction temperature to rise up to 110°C. A
special digital thermal loop control system is employed
to maximize charging current by dynamically decreasing
the battery charging current.
Thermal protection suspends the AAT3692's charging
function when internal dissipation becomes excessive,
while the OVP function remains available. The junction
over-temperature threshold is 140°C with 15°C of hys-
teresis. Once an over-temperature condition is removed,
the charging function automatically recovers.
The status monitor output pin (STAT) is designed to indi-
cate the battery charge status with open-drain structure
by directly driving one external LED. The power OK out-
put pin (POK) is targeted as a system power valid indica-
tion signal for charging.
Battery Charging Operation
Regardless of which charge input function is selected
(adapter input or USB input), the AAT3692 has three
basic modes for the battery charge cycle: precondition-
ing (trickle) charge, constant current/fast charge, and
constant voltage charge. When no automatic charge
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [e-mail] • www.skyworksinc.com
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201895B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • April 27, 2012