AAT3670ISK-4.2-T1 View Datasheet(PDF) - Analog Technology Inc
Part Name
Description
MFG CO.
'AAT3670ISK-4.2-T1' PDF : 32 Pages View PDF
Functional Block Diagram
ADP
Switch 1
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
OUT
USB
EN
ENBAT
CT
TERM
ADPSET
USBSET
ADPLIM
USBLIM
USBSEL
CHRADP
CHRUSB
Switch 2
Charge
System
Control
Temperature and
Current Sense
BAT
BATS
Voltage
Sense
Ref.
Temp.
Sense
TS
VTS
Ref.
STAT1 STAT2
Functional Description
The AAT3670 is a dual input dynamic battery
charge and power control IC. The dual input capa-
bility is designed to accommodate both AC power
adapter and USB port power sources. In addition,
this device also provides dynamic power control to
charge a single cell Li-ion battery cell and power a
system simultaneously.
The device contains separate charge regulation
pass devices to control the charge current or volt-
age for both the adapter (ADP) and USB (USB)
input power paths. The AAT3670 also contains
three additional load switches to control and route
input power to charge the battery, supply the sys-
tem load and manage power from the battery to the
system load. This charge control and switch array
permits dynamic charging of the battery cell and
control of power to the system load simultaneously.
When an input power source is applied to the
AAT3670, the device selects the adapter or USB
18
GND
input to provide power to the system load and
charge the battery. If power is present on both the
ADP and USB inputs, the system will select the
ADP input since it provides greater power levels
and charges the battery with a greater current.
Without a valid ADP/USB supply present, the bat-
tery will power the system load as long as the bat-
tery voltage is greater than 2.9V. The battery volt-
age sense circuit will disconnect the battery from
the load if the cell voltage falls below 2.9V to pro-
tect the battery cell from over-discharge which
would result in shortened battery life.
The system load current drawn from the battery is
limited internally. The AAT3670 precisely regulates
battery charge voltage and current for 4.2V Li-ion
battery cells, and the battery charge current can be
programmed up to 1.6A for ADP charging and up to
0.9A for USB charging. During battery charge, the
AAT3670 pre-conditions (trickle charge) the battery
with lower current when the battery voltage is less
than 2.9V, and it charges the battery in a constant
current mode when the battery voltage is above
3670.2007.02.1.1
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