AAT3670 [ANALOGICTECH]
1.6A Dynamic Battery Charger and Power Manager; 1.6A动态电池充电器和电源管理器
| 型号： | AAT3670 |
| 厂家： | 
ADVANCED ANALOGIC TECHNOLOGIES |
| 描述： | 1.6A Dynamic Battery Charger and Power Manager |
| 文件： | 总32页 (文件大小：661K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
™
BatteryManager
General Description
Features
The AAT3670 BatteryManager is a highly integrated
single-cell lithium-ion/polymer (Li-ion) battery charger
and system power management IC that enables simul-
taneous battery charging and full system usage without
compromising the battery's charge cycle life. It operates
with low-voltage AC adapter (ADP) and USB inputs and
requires a minimum number of external components.
•
•
•
ADP, USB, or Battery Powers System Load
Through Internal Current-Limited Switches
Simultaneous Battery Charging and System
Usage
Voltage Sensed Charge Reduction Loop
to Minimize Charge Time, Even While the
System Operates
•
•
•
•
•
•
•
Digitized Thermal Loop
Battery Power Enable (ENBAT)
Battery Charge Timer (CT)
Battery Temperature Monitoring (TS)
Battery Charge Status Report (/STATx)
Automatic Recharge Sequencing
Battery Under-Voltage, Over-Voltage, and
Over-Current Protection
The AAT3670 selects ADP or USB to power the system
load and charge the battery when ADP/USB power is
available. The AAT3670 precisely regulates battery
charge voltage and current for 4.2V Li-ion cells. Charge
current can be programmed up to 1.6A for ADP charging
and 0.9A or 0.1A for USB charging by resistors on the
ADPSET/ USBSET pins. The charge termination current
threshold is set by an external resistor on the TERM pin.
•
•
•
System Load Current Limiting
Thermal Protection
24-pin 4x4mm QFN Package
The AAT3670 has a voltage-sensed charge current
reduction loop that enables system operation without a
power shortage. When the input voltage falls below the
programmable charge reduction threshold, the device
automatically reduces the charge current until the input
voltage returns to the threshold voltage.
Applications
Battery temperature and charge state are fully monitored
for fault conditions. In the event of a battery over-volt-
age/short-circuit/over-temperature condition, the charg-
er will automatically shut down, protecting the charging
device, control system, and battery. Two status monitor
output pins (STAT1 and STAT2) are provided to indicate
battery charge status by directly driving external LEDs.
•
•
•
•
•
•
Cellular Telephones
Digital Still Cameras
Personal Data Assistants (PDAs)
Hand Held PCs
MP3 Players and PMP
Other Li-ion Battery Powered Devices
The AAT3670 is available in a Pb-free, thermally-
enhanced, space-saving 24-pin 4x4mm QFN package.
Typical Application
STAT1
OUT
System Load
BATS
BAT
STAT2
ADP
Adapter Input
CBAT
10µF
CADP
10µF
AAT3670
Single Cell
Li-Ion/Poly
Battery
USB
EN
USB Input
T
VTS
TS
CUSB
10µF
RT
Enable
Enable Battery to OUT
USB Hi/Lo Select
ENBAT
CHRADP
CHRUSB
CT
USBSEL
ADPSET
USBSET
ADPLIM
USBLIM
TERM
CT
GND
RADPSET
RUSBSET
RADPLIM
RUSBLIM
RTERM
3670.2007.02.1.1
1
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
Pin Descriptions
Pin #
Name
Type
Function
1
USBSEL
I
Logic input. High for 100% USB charge current set by USBSET; low for 20% (con-
stant current charge mode) or 50% (trickle charge mode) charge current set by the
USBSET resistor.
2, 3
4, 5
6
OUT
BAT
ADP
O
I/O
I
System load output; a capacitor with a minimum value of 10µF (including all capaci-
tance on the load of OUT) is required.
Battery pack input/output. For best operation, a 1µF ceramic capacitor should be
placed between BAT and GND.
AC adapter input, source of system load and battery charging. Minimum 1µF input
capacitor.
7
8
VTS
TS
O
I
Voltage reference for battery temperature sensing.
Battery temperature sensing input. Use an NTC resistor from TS pin to ground and
a 1% standard resistor that has equal resistance of the NTC at 25°C from VTS to
TS for battery temperature sensing. Tie TS pin to ground to disable the temperature
sensing function.
9
BATS
I
Battery sense pin.
10
CHRADP
I/O
ADP voltage sensed charge reduction programmable pin. A resistor divider from
ADP to this pin and GND sets the charge reduction threshold. When this pin is
open, the charge reduction threshold is 4.6V. If this pin is tied to the ADP pin, the
charge reduction is disabled.
11
12
13
ADPLIM
USBLIM
ADPSET
I
I
I
Connect a resistor to this pin to set the ADP input current limit (including load switch
and charger currents).
Connect a resistor to this pin to set the USB input current limit (including load switch
and charger currents).
Connect a resistor to this pin to set the ADP charge current (for trickle charge and
constant current charge). The CC current set by this pin should be less than the
current limit set by ADPLIM, otherwise the CC current will be limited by ADPLIM.
Connect a resistor to this pin to set the USB charge current (for trickle charge and
constant current charge). The CC current set by this pin should be less than the
current limit set by USBLIM, otherwise the CC current will be limited by USBLIM.
Common ground.
14
USBSET
I
15
16
GND
I/O
I
TERM
Connect a resistor to this pin to program the charge termination current threshold.
No termination current setting when this pin is pulled up to a logic high level.
ADP/USB enable input. High or floating (internal pull-up) to enable ADP/USB
switch and ADP/USB battery charging; low to disable ADP/USB switch and
ADP/USB battery charging.
17
EN
I
2
3670.2007.02.1.1
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
Pin Descriptions (continued)
Pin #
Name
Type
Function
18
CT
I
Battery charge timer input pin. Connect a capacitor to this pin to set the ADP charge
timers. No time-out for USB charging. Timers are disabled when this pin is ground-
ed. The timer is suspended if the battery temperature is not within 0 to 50ºC or is in
charge reduction (either due to the supply voltage dropping or the device tempera-
ture rising) is activated. The timer continues where it left off after the battery temper-
ature returns to normal and the device is out of the charge reduction loops.
Open drain charger status reporting.
19
20
21
22
STAT2
STAT1
N/C
O
O
Open drain charger status reporting.
No connection.
USB
I
USB input, source of system load and battery charging when ADP is not available.
Minimum 1µF input capacitor.
23
CHRUSB
ENBAT
I/O
USB voltage sensed charge reduction programmable pin. A resistor divider from
USB to this pin and GND sets the charge reduction threshold. When this pin is
open, the charge reduction threshold is 4.5V. If this pin is tied to the USB pin,
charge reduction is disabled.
24
I
Battery load switch enable, active high.
EP
Exposed paddle (bottom). Connect to ground as closely as possible to the device.
Pin Configuration
QFN44-24
(Top View)
1
2
3
4
5
6
18
17
16
15
14
13
CT
EN
TERM
GND
USBSET
ADPSET
USBSEL
OUT
OUT
BAT
BAT
ADP
3670.2007.02.1.1
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AAT3670
1.6A Dynamic Battery Charger
and Power Manager
Absolute Maximum Ratings1
Symbol
Description
Value
Units
VP
VP
ADP, USB, BAT, OUT, BATS <30ms, Duty Cycle < 10%
ADP, USB BAT, OUT, BATS Continuous
USBSEL, EN, ENBAT, STAT1, STAT2
-0.3 to 7.0
-0.3 to 6
-0.3 to 6
V
V
V
VTS, TS, CT, ADPLIM, USBLIM, ADPSET, USBSET, TERM,
CHRADP, CHRUSB
VN
-0.3 to VP + 0.3
V
TJ
Operating Junction Temperature Range
Maximum Soldering Temperature (at Leads)
-40 to 150
300
°C
°C
TLEAD
Thermal Information2
Symbol
Description
Value
Units
θJA
PD
Maximum Thermal Resistance
Maximum Power Dissipation
50
°C/W
W
2.0
1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at condi-
tions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time.
2. Mounted on a FR4 board.
4
3670.2007.02.1.1
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
Electrical Characteristics
VADP = 5V, TA = -25°C to +85°C; unless otherwise noted, typical values are TA = 25°C.
Symbol
Description
Conditions
Min
Typ
Max
Units
Operation
AC Adapter Operating Voltage
Range
VADP
VUSB
VBAT
4.35
4.35
3.0
5.5
5.5
V
V
V
USB Operating Voltage Range
Battery Operating Voltage
Range
VBAT_EOC
Rising Edge
3.6
0.3
3.6
0.3
2.9
0.1
0.5
VUVLO_ADP
VUVLO_USB
VUVLO_BAT
ADP Under-Voltage Lockout
USB Under-Voltage Lockout
V
V
Hysteresis
Rising Edge
Hysteresis
Rising Edge
2.8
3.0
BAT Under-Voltage Lockout
ADP Normal Operating Current
ADP Shutdown Mode Current
USB Normal Operating Current
USB Shutdown Mode Current
V
Hysteresis
IADP OP
VADP = VEN = 5V, ICC = 1A
1
1
1
1
mA
µA
mA
µA
_
VADP = 5V, VEN = 0V,
IADP SHDN
_
VENBAT = 0V, No Load
IUSB OP
VUSB = VEN = 5V, ICC = 0.5A
0.5
_
V
USB = 5V, VEN = 0V,
VENBAT = 0V, No Load
BAT = VBAT_EOC, VADP = GND,
IUSB_SHDN
V
IBAT_OP
Battery Operating Current
VUSB = GND, VENBAT = 5V,
No Load
45
2
80
µA
VBAT = VBAT_EOC, VADP = 5V or
IBAT_SLP
Battery Sleep Current
5
1
µA
µA
VUSB = 5V, VEN = VENBAT = 5V
IBAT SHDN
Leakage Current from BAT Pin
VBAT = VBAT EOC, VENBAT = 0V
_
_
Power Switches
RDS(ON) SWA ADP-to-OUT FET On Resistance VADP = 5.0V
0.4
0.7
0.1
Ω
Ω
Ω
_
RDS(ON) SWU USB-to-OUT FET On Resistance VUSB = 5.0V
_
RDS(ON) SWB BAT-to-OUT FET On Resistance VBAT = 4.2V
_
ADP Battery Charging FET
On Resistance
RDS(ON)_CHA
RDS(ON)_CHU
VADP = 5.0V
VUSB = 5.0V
0.4
0.7
Ω
Ω
USB Battery Charging FET
On Resistance
3670.2007.02.1.1
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AAT3670
1.6A Dynamic Battery Charger
and Power Manager
Electrical Characteristics (continued)
VADP = 5V, TA = -25°C to +85°C; unless otherwise noted, typical values are TA = 25°C.
Symbol
Description
Conditions
Min
Typ
Max
Units
Battery Charge Voltage Regulation
Output Charge Voltage
VBAT_EOC
For 4.2V Cells
4.158
2.8
4.20
2.9
4.242
3.0
V
V
V
Regulation1
VMIN
Preconditioning Voltage Threshold
Battery Recharge Voltage
Threshold
VBAT_EOC - VBAT_EOC - VBAT_EOC -
VRCH
0.17
0.1
0.05
CHRADP Open;
Reduce Charge
Current When ADP
Default ADP Charge Reduction
Threshold
4.6
is Below VCHR TH
_
VCHR_TH
V
CHRUSB Open;
Reduce Charge
Current When USB
Default USB Charge Reduction
Threshold
4.5
2.0
is Below VCHR TH
_
CHRADP and CHRUSB Pin
Voltage Accuracy
VCHR_REG
1.9
2.1
V
Current Regulation
ILIM_ADP
ILIM_USB
ILIM_BAT
Maximum ADP Current Limit
1.6
0.9
2.3
A
A
A
Maximum USB Current Limit
BAT_OUT Current Limit (Fixed)
ADP Charge Constant Current
Charge Range
ICH_CC_ADP
ICH_CC_USB_H
ICH_CC_USB_L
100
50
1600
900
mA
mA
mA
USB High-Power Charge
Constant Current Charge Range
USB Low-Power Charge
USBSEL = 5V
USBSEL = 0V
10
180
Constant Current Charge Range
I
I
CH_CC_ADP = 1A
CH_CC_USB_H = 0.5A
Constant Current Charge
Current Regulation Tolerance
ΔICH_CC/ICH_CC
-12
12
%
ICH CC USB L = 0.1A
_
_
_
%
ICH_TKL_ADP ADP Charge Trickle Charge
10
10
50
ICH CC ADP
_
_
USB High-Power Charge
ICH_TKL_USB_H
%
USBSEL = 5V
USBSEL = 0V
Trickle Charge
ICH CC USBH
_
_
USB Low-Power Charge
ICH_TKL_USB_L
%
Trickle Charge
ICH CC USBL
_ _
1. The output charge voltage accuracy is specified over the 0° to 70°C ambient temperature range; operation over the -25°C to +85°C
temperature range is guaranteed by design.
6
3670.2007.02.1.1
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
Electrical Characteristics (continued)
VADP = 5V, TA = -25°C to +85°C; unless otherwise noted, typical values are TA = 25°C.
Symbol Description
Conditions
Min
Typ
Max
Units
Current Regulation (continued)
VADPLIM
VUSBLIM
ADPLIM Pin Voltage Regulation
USBLIM Pin Voltage Regulation
2
2
2
2
2
V
V
V
V
V
VADPSET ADPSET Pin Voltage Regulation
VUSBSET USBSET Pin Voltage Regulation
VTERM
TERM Pin Voltage Regulation
Constant Current Charge Current Set Factor:
KI_CC_ADP
29300
17900
3600
ICH ADP/IADPSET
_
Constant Current Charge Current Set Factor:
KI_CC_USBH
USBSEL = 5V
USBSEL=0V
ICH USB/IUSBSET
_
Constant Current Charge Current Set Factor:
KI_CC_USBL
ICH USB/IUSBSET
_
KI_LIM ADP Current Limit Set Factor: ILIM ADP/IADPLIM
27800
17600
3500
_
_
KI_LIM USBH Current Limit Set Factor: ILIM USB/IUSBLIM
USBSEL = 5V
USBSEL = 0V
_
_
KI_LIM USBL Current Limit Set Factor: ILIM USB/IUSBLIM
_
_
KI_TERM
Termination Current Set Factor: ICH TERM/ITERM
2000
_
Logic Control/Protection
VEN
VEN
Input High Threshold
1.6
V
V
Input Low Threshold
0.4
0.4
/STATx Pin
Sinks 8mA
VSTATx
TC
TTKL
VOVP
Output Low Voltage
V
Fast Charge (Constant Current and Constant
Voltage Charges Together) Timeout
CCT
=
ADP
6
hour
100nF USB
ADP
infinite
Tc/8
Trickle Charge Timeout
USB
infinite
Battery Over-Voltage Protection
Threshold
VBAT_EOC + VBAT_EOC + VBAT_EOC +
V
0.1
0.15
0.2
Battery Charge Over-Current
Protection Threshold
IOCP
IVTS
In All Modes
VVTS = 2.5V
100
%ICH_CC
mA
VTS Sourcing Capability
1
3670.2007.02.1.1
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AAT3670
1.6A Dynamic Battery Charger
and Power Manager
Electrical Characteristics (continued)
VADP = 5V, TA = -25°C to +85°C; unless otherwise noted, typical values are TA = 25°C.
Symbol
Description
Conditions
Min
Typ
Max
Units
Logic Control/Protection (continued)
Threshold
Hysteresis
Threshold
Hysteresis
28
70
30
2
32
74
TS1
TS2
TS Hot Temperature Fault
TS Cold Temperature Fault
%VTS
%VTS
ºC
72
2
Digital Thermal Loop Entry
Threshold
TLOOP_IN
TLOOP_OUT
TLOOP_REG
TSHDN
For ADP Charging
For ADP Charging
For ADP Charging
115
95
Digital Thermal Loop Exit
Threshold
ºC
Digital Thermal Loop Regulated
Temperature
100
ºC
Chip Thermal Shutdown
Temperature
Threshold
Hysteresis
140
15
ºC
8
3670.2007.02.1.1
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
Typical Characteristics
Constant Current vs. Set Resistor
(VIN = 5V; VBAT = 3.5V)
Adapter Mode Supply Current vs. ADPSET Resistor
(VIN = 5V; VBAT = 3.5V)
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
0.8
ADP
0.7
ICCM
0.6
0.5
0.4
USBH
USBL
ITRICKLE
0.3
0.2
0.1
10
100
1000
10
100
1000
Set Resistor (kΩΩ)
ADPSET Resistor (kΩΩ)
USB Mode Supply Current vs. USBSET Resistor
(USBL; VIN = 5V; VBAT = 3.5V)
USB Mode Supply Current vs. USBSET Resistor
(USBH; VIN = 5V; VBAT = 3.5V)
0.8
0.7
0.8
0.7
ICCM
ICCM
0.6
0.5
0.4
0.3
0.2
0.1
0.6
ITRICKLE
0.5
0.4
0.3
0.2
0.1
ITRICKLE
10
100
1000
10
100
1000
USBSET Resistor (kΩΩ)
USBSET Resistor (kΩΩ)
End of Charge Voltage vs. Supply Voltage
End of Charge Voltage vs. Temperature
4.24
4.24
4.22
4.20
4.18
4.16
4.22
4.20
4.18
4.16
USBH
ADP
USBH
USBL
ADP
USBL
-40
-15
10
35
60
85
4.5
4.75
5.0
5.25
5.5
Supply Voltage (V)
Temperature (°°C)
3670.2007.02.1.1
9
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
Typical Characteristics
Recharge Threshold Voltage vs. Temperature
(VIN = 5.0V)
Preconditioning Threshold Voltage vs. Temperature
(VIN = 5.0V)
3.05
3.00
4.20
4.16
ADP
ADP
USBH
2.95
4.12
USBH
2.90
4.08
USBL
2.85
4.04
USBL
2.80
4.00
3.96
2.75
-40
-15
10
35
60
85
-40
-15
10
35
60
85
Temperature (°°C)
Temperature (°°C)
BAT to OUT Switch Voltage vs. Load Current
(VBAT = 3.95V)
Preconditioning Charging Current vs. Temperature
(VIN = 5.0V)
1.2
120
ADP
1
-40°C
0.8
100
25°C
0.6
0.4
0.2
80
60
40
0
+85°C
-0.2
-0.4
-0.6
-0.8
-1
USBH, USBL
20
0
-1.2
-40
-15
10
35
60
85
0
200 400 600 800 1000 1200 1400 1600 1800 2000 2200
Load Current (mA)
Temperature (°°C)
Charging Current vs. Battery Voltage
(ADP; ADPSET = 57.6KΩΩ)
Charging Current vs. Battery Voltage
(USBH; USBSET = 71.5KΩΩ)
1200
1000
800
600
400
200
0
600
500
400
300
200
100
0
2.5
2.9
3.3
3.7
4.1
4.5
2.5
2.9
3.3
3.7
4.1
4.5
Battery Voltage (V)
Battery Voltage (V)
10
3670.2007.02.1.1
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
Typical Characteristics
Charging Current vs. Battery Voltage
(USBL; USBSET = 71.5KΩΩ)
Constant Charge Current vs. Temperature
(VIN = 5.0V)
1100
120
100
80
60
40
20
0
1000
900
800
700
600
500
400
300
200
100
0
ADP
USBH
USBL
-40
-15
10
35
60
85
2.5
2.9
3.3
3.7
4.1
4.5
Battery Voltage (V)
Temperature (°°C)
Constant Charging Current vs. Supply Voltage
(ADP; CHRADP = Open; ADPSET = 57.6kΩΩ)
Constant Charging Current vs. Supply Voltage
(ADP; CHRADP = USB; ADPSET = 57.6kΩΩ)
1200
1000
1200
VBAT = 3.3V
1000
800
800
VBAT = 3.6V
VBAT = 3.3V, 3.6V, 3.9V
600
400
200
0
600
VBAT = 3.9V
400
200
0
4.0
4.5
5.0
5.5
6.0
4.0
4.5
5.0
5.5
6.0
Supply Voltage (V)
Supply Voltage (V)
Constant Charging Current vs. Supply Voltage
(USBL; CHRUSB = Open; USBSET = 71.5kΩΩ)
Constant Charging Current vs. Supply Voltage
(USBL; CHRUSB = USB; USBSET = 71.5kΩΩ)
120
120
VBAT = 3.3V, 3.6V
VBAT = 3.3V
100
100
80
80
VBAT = 3.6V
VBAT = 3.9V
60
60
40
20
0
VBAT = 3.9V
40
20
0
4.0
4.5
5.0
5.5
6.0
4.0
4.5
5.0
5.5
6.0
Supply Voltage (V)
Supply Voltage (V)
3670.2007.02.1.1
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AAT3670
1.6A Dynamic Battery Charger
and Power Manager
Typical Characteristics
Constant Charging Current vs. Supply Voltage
(USBH; CHRUSB = Open; USBSET = 71.5kΩΩ)
Constant Charging Current vs. Supply Voltage
(USBH; CHRUSB = USB; USBSET = 71.5kΩΩ)
600
600
VBAT = 3.3V
VBAT = 3.3V
500
500
VBAT = 3.9V
400
400
VBAT = 3.6V
VBAT = 3.6V
300
300
VBAT = 3.9V
200
200
100
0
100
0
4.0
4.5
5.0
5.5
6.0
4.0
4.5
5.0
5.5
6.0
Supply Voltage (V)
Supply Voltage (V)
Constant Charging Current vs.
Supply Voltage
Constant Charging Current vs.
Supply Voltage
(ADP; CHRADP = Open; VBAT = 3.6V; ADPSET = 57.6KΩΩ)
1200
(USBL; CHRUSB = Open; VBAT = 3.6V; USBSET = 71.5KΩ
120
-40°C
100
1000
+85°C
+25°C
80
25°C
800
+85°C
60
40
20
0
600
400
-40°C
200
0
4.3
4.4
4.5
4.6
4.7
4.8
4.9
4.3
4.4
4.5
4.6
4.7
4.8
4.9
Supply Voltage (V)
Supply Voltage (V)
Constant Charging Current vs.
Supply Voltage
(USBH; CHRUSB = Open; VBAT = 3.6V; USBSET = 71.5KΩ)
600
-40°C
500
400
300
200
100
0
25°C
+85°C
4.3
4.4
4.5
4.6
4.7
4.8
4.9
Supply Voltage (V)
12
3670.2007.02.1.1
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
Typical Characteristics
VIH vs. Supply Voltage
(ADP or USBL or USBH; EN = Rising)
VIL vs. Supply Voltage
(ADP or USBL or USBH; EN = Falling)
1.2
1.1
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
-40°C
25°C
-40°C
25°C
1.0
0.9
0.8
0.7
0.6
0.5
0.4
85°C
+85°C
4.2
4.4
4.6
4.8
5.0
5.2
5.4
5.6
5.8
6.0
4.2
4.4
4.6
4.8
5.0
5.2
5.4
5.6
5.8
6.0
Supply Voltage (V)
Supply Voltage (V)
VIH vs. Supply Voltage
(ENBAT = Rising)
VIL vs. Supply Voltage
(ENBAT = Falling)
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
25°C
-40°C
-40°C
25°C
85°C
85°C
4.2
4.4
4.6
4.8
5.0
5.2
5.4
5.6
5.8
6.0
4.2
4.4
4.6
4.8
5.0
5.2
5.4
5.6
5.8
6.0
Battery Voltage (V)
Battery Voltage (V)
Adapter and Charging Current vs. Output Current
(VBAT = 3.6V)
USB and Charging Current vs. Output Current
(USBL; VBAT = 3.6V)
1800
400
200
IADP
1600
1400
1200
1000
800
0
IUSBL
-200
ICH
ICH
-400
-600
-800
600
400
200
-1000
0
200
400
600
800
1000
0
200
400
600
800
1000
Output Current (mA)
Output Current (mA)
3670.2007.02.1.1
13
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
Typical Characteristics
USB and Charging Current vs. Output Current
(USBH; VBAT = 3.6V)
ADP Charge Current vs. Time
1200
1000
5.0
4.5
4.0
Charge Reduction
Mode Activated
800
1.0
0.5
0.0
IUSBH
600
400
ICH
200
1.0
0.5
0.0
0
-200
0
1
2
3
4
5
0
200
400
600
800
1000
Output Current (mA)
Time
USB Charge Current vs. Time
(USBH)
CT Current vs. Temperature
(CT = 0.1F)
5.0
4.5
4.0
550
548
546
544
542
540
538
536
534
532
Charge Reduction
Mode Activated
Constant
Current
0.5
0.0
Preconditioning
0.5
0.0
0
1
2
3
4
-40
-15
10
35
60
85
Time
Temperature (°°C)
CT Timeout vs. Temperature
(CT = 0.1F)
CT Pin Capacitance vs. Counter Timeout
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
7
6
5
4
3
2
1
0
Preconditioning Timeout
Constant Current
Constant Current Timeout
Preconditioning
0
10
20
30
40
50
60
-40
-15
10
35
60
85
Temperature (°C)
Time (hours)
14
3670.2007.02.1.1
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
Typical Characteristics
Percentage of VVTS vs. Temperature
(ADP or USBH or USBL; VIN = 5V)
Total Input Current vs. Output Current
(VBAT = 3.6V)
1800
1600
1400
1200
1000
800
80
70
60
50
40
30
20
10
0
IADP
VTS2
IUSBH
VTS1
600
IUSBL
400
200
0
0
200
400
600
800
1000
-40
-15
10
35
60
85
Temperature (°°C)
Output Current (mA)
Transient Response of OUT
When Switching from ADP to BAT
Transient Response of OUT
When Switching from BAT to ADP
➜
(VADP = 5V 0V)
➜
(VADP = 0V 5V)
OUT
5
4
3
2
1
0
5
4
3
2
1
0
OUT
BAT
ADP
BAT
ADP
Time (500µs/div)
Time (500µs/div)
Transient Response of OUT
When Switching From USBH to BAT
Transient Response of OUT
When Switching From BAT to USBH
➜
➜
(VUSBH = 5V 0V; RLOAD = 7.8Ω)
(VUSBH = 0V 5V; RLOAD = 7.8Ω)
USBH
USBH
BAT
5
4
3
2
1
0
5
4
3
2
1
0
OUT
BAT
OUT
Time (500µs/div)
Time (500µs/div)
3670.2007.02.1.1
15
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
Typical Characteristics
Transient Response of OUT
When Switching From USBL to BAT
Transient Response of OUT
When Switching From BAT to USBL
➜
➜
(VUSBL = 5V 0V; RLOAD = 50Ω)
(VUSBL = 0V 5V; RLOAD = 50Ω)
USBL
USBL
5
4
3
2
1
0
5
4
3
2
1
0
BAT
OUT
BAT
OUT
Time (500µs/div)
Time (500µs/div)
Transient Response of OUT
When Switching From USBL to ADP
Transient Response of OUT
When Switching From ADP to USBL
➜
➜
(VADP = 5V 0V; RLOAD = 50Ω)
(VADP = 0V 5V; RLOAD = 50Ω)
USBL
USBL
5
4
3
2
1
0
5
4
3
2
1
0
OUT
OUT
ADP
ADP
Time (500µs/div)
Time (500µs/div)
Transient Response of OUT
When Switching From ADP to USBH
Transient Response of OUT
When Switching From USBH to ADP
➜
➜
(VADP = 0V 5V; RLOAD = 7.8Ω)
(VADP = 5V 0V; RLOAD = 7.8Ω)
USBH
OUT
USBH
5
4
3
2
1
0
5
4
3
2
1
0
OUT
ADP
ADP
Time (100µs/div)
Time (100µs/div)
16
3670.2007.02.1.1
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
Typical Characteristics
Transient Response of OUT When ADP is On
When USBH Switching from On to Off
Transient Response of OUT When ADP is On
When USBH Switching from Off to On
➜
➜
(VUSBH = 5V 0V; RLOAD = 7.8Ω)
(VUSBH = 0V 5V; RLOAD = 7.8Ω)
ADP
ADP
5
5
4
4
OUT
OUT
3
3
2
1
0
USBH
2
1
0
USBH
Time (500µs/div)
Time (500µs/div)
Transient Response of OUT
When Switching From ADP to USBL
Transient Response of OUT
When Switching From USBL to ADP
➜
➜
(VUSBL = 5V 0V; RLOAD = 50Ω)
(VUSBL = 0V 5V; RLOAD = 50Ω)
ADP, OUT
ADP, OUT
5
4
3
2
1
0
5
4
3
2
1
0
USBL
USBL
Time (500µs/div)
Time (500µs/div)
3670.2007.02.1.1
17
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
Functional Block Diagram
Switch 1
ADP
OUT
Switch 2
USB
EN
ENBAT
CT
BAT
BATS
TERM
Temperature and
Current Sense
ADPSET
Voltage
Sense
Ref.
Charge
System
Control
USBSET
ADPLIM
USBLIM
USBSEL
CHRADP
CHRUSB
TS
Temp.
Sense
VTS
Ref.
GND
STAT1 STAT2
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.
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.
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
When an input power source is applied to the
AAT3670, the device selects the adapter or USB
18
3670.2007.02.1.1
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
2.9V. When the battery voltage rises to 4.2V, the
charger will automatically switch to a constant volt-
age mode until the charge current is reduced to the
programmed charge termination current threshold.
The internal arrangement of load switches and
charge regulation device also provide dynamic
power sourcing to the system load. If the system
load exceeds the input current supply from the
adapter or USB source, additional current can be
sourced from the battery cell. At all times, the
device will manage distribution of power between
the source, the battery and the system simultane-
ously in order to support system power needs and
charge the battery cell with the maximum amount
of current possible.
the charging current to prevent the device from
thermal shutdown. The digital thermal loop will
maintain the maximum possible battery charging
current for the given set of input to output power
dissipation and ambient temperature conditions.
The digital thermal loop control is dynamic in the
sense that it will continue to adjust the battery
charging current as operating conditions change.
The digital thermal loop will reset and resume nor-
mal operation when the power dissipation or over-
temperature conditions are removed.
Battery temperature and charge state are fully mon-
itored for fault conditions. In the event of an over-
voltage, over-current, or over-temperature failure,
the device will automatically shut down, thus pro-
tecting the charging device, control system, and the
battery under charge. In addition to internal charge
controller thermal protection, the AAT3670 also pro-
vides a temperature sense feedback function
(VTS/TS pins) from the battery to shut down the
device in the event the battery exceeds its own ther-
mal limit during charging. All fault events are report-
ed to the user by two simple status LEDs.
The AAT3670 has a unique internal charge current
reduction loop control that will prevent an input
source from overload. In the case of USB charging
from a USB port VBUS supply, there are two events
which need to be guarded against. The first is
charging from a defective or inadequate USB host
supply; the second problem could arise if the pro-
grammed USB charge current plus the system sup-
ply demand through the AAT3670 exceeds the abil-
ity of a given USB port. In either case, the AAT3670
charge reduction (CHR) loop will activate when the
input source to the USB input drops below the
VCHR_TH threshold of 4.5V. The CHR loop will auto-
matically reduce the charge current to the battery
until the supply voltage recovers to a point above
the VCHR_TH threshold. The CHR loop protection
system also operates in the adapter input mode
with a 4.6V VCHR_TH threshold. This protects the
charger, system and source supply in the event an
adapter or power source does not meet the ADP
charging mode specification. In USB or adapter
mode charging, the CHR system will permit the
charging of a battery cell with the maximum possi-
ble amount of charge current for any given source
fault condition.
Charging Operation
The AAT3670 has four basic modes for the battery
charge cycle regardless of which charge input
function is selected, either the adapter input or
USB input: pre-conditioning/trickle charge, con-
stant current fast charge, constant voltage, and end
of charge/sleep mode.
Battery Preconditioning
Before the start of charging, the AAT3670 checks
several conditions in order to assure a safe charg-
ing environment. The input supply must be above
the minimum operating voltage, or under-voltage
lockout threshold (VUVLO), for the charging
sequence to begin. Also, the cell temperature, as
reported by a thermistor connected to the TS pin
from the battery, must be within the proper window
for safe charging. When these conditions have
been met and a battery is connected to the BAT pin,
the AAT3670 checks the state of the battery via the
battery voltage sensing (BATS) pin. If the cell volt-
age is below the preconditioning voltage threshold
(VMIN), the AAT3670 begins preconditioning the cell.
During battery charging, the device temperature
will rise. In some cases with adapter (ADP) charg-
ing, the power dissipation in the device may cause
the junction temperature to rise to close to its ther-
mal shutdown threshold. In the event of an internal
over-temperature condition caused by excessive
ambient operating temperature or excessive power
dissipation condition, the AAT3670 enables a digi-
tally controlled thermal loop system that will reduce
3670.2007.02.1.1
19
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
Preconditioning
Trickle Charge
Phase
Constant Current
Charge Phase
Constant Voltage
Charge Phase
End of Charge Voltage
Regulated Current
(4.2V)
I = Max CC
Constant Current Mode
Voltage Threshold
(2.9V)
Trickle Charge
Charge Termination Current
Figure 1: Current vs. Voltage Profile During Charging Phases.
The battery preconditioning trickle charge current
voltage reaches output charge regulation threshold
(VBAT_EOC) during constant current fast charge
phase. The regulation voltage level is factory pro-
grammed to 4.2V (±1%). The charge current in the
constant voltage mode drops as the battery cell
under charge reaches its maximum capacity.
is equal to the fast charge constant current divided
by 10 for the adapter and USB high input modes.
For example, if the programmed fast charge cur-
rent is 500mA, then the preconditioning mode
(trickle charge) current will be 50mA. In the USB
low charging mode, the preconditioning current is
set to the programmed fast charge current divided
by two. Cell preconditioning is a safety precaution
for a deeply discharged battery and also aids in
limiting power dissipation in the charge control
pass transistor when the voltage across the device
is at the greatest potential.
End of Charge Cycle Termination and
Recharge Sequence
When the charge current drops to the user pro-
grammed charge termination current at the end of
the constant voltage charging phase, the device
terminates charging and enters the sleep state.
The charger will remain in the sleep state until the
battery voltage decreases to a level below the bat-
tery recharge voltage threshold (VRCH). The charge
termination current is programmed via the RTERM
resistor.
Fast Charge/Constant Current Charging
Battery cell preconditioning continues until the volt-
age measured by the battery sense (BATS) pin
exceeds the preconditioning voltage threshold
(VMIN). At this point, the AAT3670 begins constant-
current charging fast charging phase. The fast
charge constant current (ICC) level is determined by
the charge mode (ADP, USBH or USBL) and is pro-
grammed by the user via the RADPSET and RUSBSET
resistors. The AAT3670 remains in constant current
charge mode until the battery reaches the voltage
When the input supply is disconnected, the charg-
er also automatically enters power-saving sleep
mode. Only consuming an ultra-low 1µA in sleep
mode, the AAT3670 minimizes battery drain when
not charging. This feature is particularly useful in
applications where the input supply level may fall
below the usable range of the charge reduction
control or under-voltage lockout level. In such
cases where the AAT3670 input voltage drops, the
device will enter the sleep mode and automatically
resume charging once the input supply has recov-
ered from its fault condition.
regulation point, VBAT_EOC
.
Constant Voltage Charging
The charge control system transitions to a regulated
constant voltage charging mode when the battery
20
3670.2007.02.1.1
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
connected to the CHRADP pin. The ADP charge
reduction feature may be disabled by shorting the
CHRADP pin directly to the ADP input pin.
Applications Information
AC Adapter/USB System Power
Charging
The following equation may be used to approxi-
mate the ADP charge reduction threshold above or
below 4.5V:
Adapter Input Mode
In the adapter mode, constant current charge lev-
els up to 1.6A may be programmed by the user.
The AAT3670 system control will always select the
adapter input over the USB supply input when ever
voltage is present on the ADP pin. The ADP input
will operate over a range from 4.35V to 5.5V.
2.0V
(R12/[R12 + R11])
Eq. 1: VADPCHR
=
where R11and R12 < 500kΩ.
The constant fast charge current for the adapter
input mode is set by the RADPSET resistor connected
between the ADPSET pin and ground. The battery
preconditioning or trickle charge current is fixed at
10% of the programmed fast charge constant current
level. Refer to Table 2 for recommended RADPSET
values for a desired constant current charge level.
Battery charging states will be indicated via the
STAT1 and STAT2 display LEDs. Please refer to the
Battery Charge Status Indication discussion for fur-
ther details on data reporting.
ADP
VADP
R11
850k
CHRADP
VCHR = 2.0V
R12
650k
ADP Charge Reduction
Under normal operation, the AAT3670 should be
operated from an adapter power source with a suffi-
cient capacity to supply the desired constant charge
current plus any additional load which may be
placed on the source by the operating system. In the
event that the power source to the ADP pin is unable
to provide the programmed fast charge constant cur-
rent, or if the system under charge must also share
supply current with other functions, the AAT3670 will
automatically reduce the ADP fast charge current
level to maintain the integrity of the source supply,
power the operating system, and charge the battery
cell with the remaining available current.
Figure 2: Internal Equivalent Circuit for the
CHRADP Pin.
Adapter Input Charge Inhibit and Resume
The AAT3670 has an under-voltage lockout
(UVLO) and power on reset feature to protect the
charger IC in the event the input supply to the
adapter pin drops below the UVLO threshold.
Under a UVLO condition, the charger will suspend
the charging process. When power is re-applied to
the adapter pin or the UVLO condition recovers,
the system charge control will asses the state of
charge on the battery cell and will automatically
resume charging in the appropriate mode for the
condition of the battery.
The ADP charge reduction system becomes active
when the voltage on the ADP input falls below the
ADP charge reduction threshold (VCHRADP), which is
preset to 4.6V. Should the input supply drop below
the VCHRADP threshold, the charge reduction system
will reduce the fast charge current level in a linear
fashion until the voltage sensed on the ADP input
recovers to a point above the charge reduction
threshold voltage. The ADP charge reduction
threshold (VCHRADP) may be externally set to a value
other than 4.6V by placing a resistor divider network
between the ADP pin and ground with the center
USB Input Mode
The AAT3670 provides an input for intelligent USB
charging. When no voltage is present on the
adapter input pin, the charge controller will auto-
matically switch to accepting power from the USB
input. The USB charge mode provides two pro-
grammable fast charge levels, USB high (USBH)
3670.2007.02.1.1
21
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
and USB low (USBL). The USBH mode can be set
as high as 900mA; however for most applications
utilizing a USB port as the source supply, 500mA is
the typical default USBH value and USBL is sub-
sequently set for 100mA. In the USBL fast charge
mode, the constant charging current is set to 20
percent of the programmed USBH. More simply
put, the USBL low fast charge level = USBH divid-
ed by five. The USBH or USBL modes may be
externally selected by USB select pin (USBSEL).
between VUSB and ground with the center connect-
ed to the CHRUSB pin. The USB charge reduction
feature may be disabled by shorting the CHRUSB
pin directly to the USB input pin.
The following equation may be used to approximate
a USB charge reduction threshold below 4.5V:
2.0V
(R2/[R2 + R1])
Eq. 2: VUSBCHR
=
In the USBH mode, the battery cell preconditioning
or trickle charge current is fixed at 10 percent of the
programmed fast charge constant current. In the
USBL mode, the trickle charge current is only
reduced to 50 percent of the programmed fast
charge constant current level.
where R1 and R2 < 1MΩ
USB
VUSB
When the USBSEL pin is connected to a logic high
level, the USBH level will be active. Conversely,
when USBSEL is pulled to a logic low level (ground)
the USBL level will be used for fast charging. Refer
to Table 2 for the recommended RUSBSET value to
program the desired USB input constant current
charge levels.
R1
1.0M
CHRUSB
VCHR = 2.0V
R2
800k
USB Charge Reduction
In many instances, product system designers have
an issue of not knowing the real properties of a
potential USB port to be used to supply power to
the battery charger. Typical powered USB ports
commonly found on desktop and notebook PCs
should supply up to 500mA. In the event a USB
port being used to supply the charger is unable to
provide the programmed fast charge current, or if
the system under charge must also share supply
current with other functions causing an overload to
the USB port, the AAT3670 will automatically
reduce USB fast charge current to maintain port
integrity and protect the host system.
Figure 3: Internal Equivalent Circuit for the
CHRUSB Pin.
USB Input Charge Inhibit and Resume
The AAT3670 under-voltage lockout (UVLO) and
power-on reset feature will function when the USB
input pin voltage level drops below the UVLO
threshold. At this point the charger will suspend
charging. When power is re-applied to the USB 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.
The USB charge reduction system becomes active
when the voltage on the USB input falls below the
USB charge reduction threshold (VCHRUSB), which is
typically 4.5V. Regardless of which USB charge
function is selected (USBH or USBL), the charge
reduction system will reduce the fast charge current
level in a linear fashion until the voltage sensed on
the USB input recovers above the charge reduction
threshold voltage. The USB charge reduction
threshold (VCHRUSB) may be externally set to a value
lower than 4.5V by placing a resistor divider network
End of Charge Termination
The AAT3670 provides a user-programmable
charge termination current at the end of the charge
cycles. When the battery cell voltage as sensed by
the BATS pin reaches 4.2V, the charge control will
transition from constant current fast charge mode to
constant voltage mode. In constant voltage mode,
the battery cell voltage will be regulated at 4.2V.
The charge current will drop as the battery reaches
its full charge capacity. When the charge current
22
3670.2007.02.1.1
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
drops to the programmed end of charge (EOC) cur-
rent, the charge cycle is complete and the charge
controller terminates the charging process.
the end-of-charge function will be disabled and the
battery will float charge in the constant voltage
mode indefinitely or until the cell voltage is brought
below the constant voltage threshold.
The charge termination current is user pro-
grammed by the value of RTERM, which is connect-
ed between the TERM pin and ground. Use the
values listed in Table 1 to set the desired charge
termination current. The programmed charge ter-
mination current will remain at the same set level
regardless of which fast charge ADP, USBH or
USBL constant current mode is selected.
System Power Output
The power to the system is supplied via the OUT
pin. OUT will source power from either the ADP or
USB inputs when an external power source is
applied. When the battery charging function is com-
plete and the charging power source is removed,
the system will be powered from the battery via
Load Switch 3, referring to the AAT3670 block dia-
gram. The maximum current that can be supplied
from the ADP or USB inputs to a system load is
bounded by the user programmed ADPLIM and
USBLIM level. If the current consumption from the
system load exceeds that of the ADP or USB input
sources, the IC will draw current from the battery to
make up the difference as long as the battery cell
voltage remains above 2.9V. Power from the bat-
tery to the OUT pin is controlled by the ENBAT func-
tion. When the ENBAT is disabled the leakage cur-
rent from the battery to the load is less than 1µA.
Ω
ITERM (mA)
RTERM (k )
320
174
125
95
11.0
21.0
30.9
41.2
51.1
61.9
71.5
80.6
90.9
100.0
110.0
77
64
58
50
49
42
37
Battery Connection and Battery Voltage
Sensing
Table 1: Charge Termination Current
Programming Resistor Values.
Battery Connection
If the desired end of charge termination current
level is not listed in Table 1, the TERM resistor
value may be calculated by the following equation:
The single cell Li-ion battery should be connected
between the BAT pin and ground. The internal load
switching network will connect the battery to the
system load and apply the charging current.
For the Adapter input mode:
Battery Voltage Sensing
The BATS pin is provided to employ an accurate volt-
age sensing capability to measure the terminal volt-
age at the battery cell being charged. This function
reduces measured battery cell voltage error between
the battery terminal and the charge control IC. The
AAT3670 charge control circuit will base charging
mode states upon the voltage 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 con-
cern of the battery sense function inadvertently
becoming an open circuit, the BATS pin may be ter-
minated to the BAT pin using a 10Ω resistor. Under
normal operation, the connection to the battery ter-
V
⎛
⎝
⎞
⎠
TERM
RTERM = K ·
ICC
Where:
K
= KI_TERM = 2000
VTERM = 2V
ICC
= Fast charge constant current
The constants K and VTERM are specified in the
Typical Characteristics section of this datasheet.
The end-of-charge termination current function can
be disabled by pulling the TERM pin high via con-
necting the TERM pin to the BAT pin. In this state,
3670.2007.02.1.1
23
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
minal will be close to 0Ω; if the BATS connection
becomes an open circuit, the 10Ω will provide feed-
back to the BATS pin from the BAT connection will a
1mV or less loss in sensed voltage accuracy.
USB charge mode. When the USBSEL pin is pulled
to a voltage level above the VUSBSEL(H) threshold, the
USBH current level will be selected. Conversely, this
pin should be pulled below the VUSBSEL(L) threshold
to enable the USBL charge level; the USBL charge
current will be set to 20% of the set USBH level. For
typical USB charging applications, the USBH and
USBL functions are fixed for 500mA and 100mA
USB fast charge levels. However, the charge level of
USBH may be set from 50mA to 900mA and USBL
will in turn be fixed at 20% of the USBH level
depending upon the system design requirements for
a given USB charge application. Refer to Table 2
and Figure 4 for recommended RUSBSET values.
Enable
The AAT3670 provides an enable function to con-
trol the charger IC on and off. The enable (EN) pin
is active high. When pulled to a logic low level, the
AAT3670 will be shut down and forced into the
sleep state. Charging will be halted regardless of
the battery voltage or charging state. When the
device is 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 cell voltage.
ICC
(mA)
ADP
USBH
USBL
RSET (kΩ) RSET (kΩ) RSET (kΩ)
Battery Enable
50
90
1300
681
590
412
309
249
205
154
121
93.1
73.2
64.9
57.6
48.7
38.3
34.8
750
453
383
249
187
150
124
90.9
71.5
54.9
43.2
38.3
150
80.6
71.5
47.5
34.8
Since the AAT3670 provides battery power switching
as well as charging function, a battery enable pin
(ENBAT) is provided so the power from the battery via
the BAT pin to the OUT pin may be externally con-
trolled. The ENBAT function allows the user to control
power to the systems regardless of charging state,
input power source, or charge enable (EN) state.
100
150
200
250
300
400
500
650
800
900
1000
1200
1500
1600
It may be desirable for some system designs to dis-
connect the battery from the load during charging.
This may be accomplished by pulling the ENBAT
pin low, while the device is enabled for charging
(EN high).
Programming Charge Current
The fast charge constant current charge level for
both adapter and USB input modes are pro-
grammed with set resistors placed between the
ADPSET or USBSET pins and ground. The accu-
racy of the fast charge constant current and the
preconditioning trickle charge current are dominat-
ed by the tolerance of the set resistor used. For
this reason, 1% tolerance metal film resistors are
recommended for this set resistor function.
Table 2: RSET Values.
1800
1600
1400
1200
1000
800
USBH
ADP
Fast charge constant current levels from 50mA to
1.6A may be set by selecting the appropriate resis-
tor value from Table 2. The RADPSET resistor should
be connected between the ADPSET pin and ground.
600
USBL
400
200
0
10
100
1000
10000
The USB input fast charge constant current charge
control provides up to 900mA of charge current and
is set in the USBH mode. The USBSEL pin is used
to select the high or low charge current levels in the
RSET (kΩ)
Figure 4: Fast Charge Current vs. Set Resistor
(VIN = 5V; VBAT = 3.5V).
24
3670.2007.02.1.1
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
If the desired current charge current level is not list-
ed in Table 2, the ADPSET and USBSET resistor
values may be calculated by the following equations:
The initial thermal loop current can be estimated by
the following equations:
In ADP mode: ITLOOP = ICCADP · 0.44
In USB mode: ITLOOP = ICCUSBH · 0.44
For the Adapter input mode:
The thermal loop control re-evaluates the internal
die temperature every three seconds and adjusts
the fast charge current back up in small steps up
to the full fast charge current level or until an equi-
librium current is discovered and maximized for
the given ambient temperature condition. In this
manner, the thermal loop controls the system
charge level. The AAT3670 will always provide the
highest possible level of constant current in the
fast charge mode for any given ambient tempera-
ture condition.
V
⎛
⎝
⎞
ADPSET
RADPSET = K ·
ICC
⎠
Where:
K
= KI_CCADP = 29300
VADPSET = 2V
ICC
= Fast Charge Constant Current
For the USB input mode:
V
Programmable Watchdog Timer
⎛
⎝
⎞
USBSET
RUSBSET = K ·
ICC
The AAT3670 contains a watchdog timing circuit
which operates only in adapter charging mode.
Typically a 0.1µF ceramic capacitor is connected
between the CT pin and ground. When a 0.1µF
ceramic capacitor is used, the device will time a
shutdown condition if the trickle charge mode
exceeds 45 minutes. When the device transitions
to the trickle charge to the fast charge constant cur-
rent mode and then to the constant voltage mode,
the timing counter is reset and will time out after 3
hours for each mode.
⎠
Where:
K
K
= KI_CCUSBH = 17900 (USBH)
= KI_CCUSBL = 3600 (USBL)
VUSBSET = 2V
ICC
= Fast Charge Constant Current
All constants K and VADP/USBSET are specified in the
Typical Characteristics section of this datasheet.
Summary for a 0.1µF used for the timing capacitor:
Trickle Charge (TC) time out = 45 minutes
Protection Circuitry
Thermal Loop Control
Fast Charge Constant Current (CC) time out =
3 hours
Due to the integrated nature of the linear charging
control pass devices for both the adapter and USB
modes, a special thermal loop control system has
been employed to maximize charging current under
all operating conditions. The thermal management
system measures the internal circuit die temperature
and reduces the charge current when the device
exceeds a preset internal temperature control
threshold. Once the thermal loop control becomes
active, the constant charge current is initially
reduced by a factor of 0.44.
Constant Voltage (VC) mode time out = 3 hours
The CT pin is driven by a constant current source
and will provide a linear response to increases in
the timing capacitor value. Thus, if the timing
capacitor were to be doubled from the nominal
0.1µF value, the time out time of the CC + CV
modes would be doubled. The corresponding trick-
le charge time out time would be the combined CC
+ VC time divided by 8.
3670.2007.02.1.1
25
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
If the programmable watchdog timer function is not
needed it may be disabled the terminating the CT
pin to ground. The CT pin should not be left float-
ing or un-terminated; this will cause errors in the
internal timing control circuit.
Ω
Ω
ICC (mA)
RADPLIM (k )
RUSBLIM (k )
50
90
1300
681
590
412
309
249
205
154
121
93.1
73.2
64.9
57.6
48.7
38.3
34.8
750
453
383
249
187
150
124
90.9
71.5
54.9
43.2
38.3
100
150
200
250
300
400
500
650
800
900
1000
1200
1500
1600
The charge timer control will suspend the timing
count in any given mode in the event a fault condi-
tion occurs. Such fault conditions include digital
thermal loop charge current reduction, ADP or USB
charge reduction, battery temperature fault, and
battery current sharing with the output during the
charging cycle. When the fault condition recovers,
the counter will resume the timing function. The
charge timer will automatically reset when the
AAT3670 enable pin is reset or cycled off and on.
The constant current provided to charge the timing
capacitor is very small and this pin is susceptible to
noise and changes in capacitance value.
Therefore, the timing capacitor should be physical-
ly located on the printed circuit board layout as
close as possible to the CT pin. Since the accura-
cy of the internal timer is determined by the capac-
itance value, a 10% tolerance or better ceramic
capacitor is recommended. Ceramic capacitor
materials such as X7R and X5R type are a good
choice for this application.
Table 3: Current Limit Programming
Resistor Values.
If the desired charge current limit level is not listed in
Table 3, the ADPLIM and USBLIM set resistor val-
ues may be calculated by the following equations:
For the Adapter input mode:
Over-Current Protection
V
⎛
⎝
⎞
ADPLIM
The AAT3670 provides over-current protection to
both the battery and system output modes for both
the ADP and USB input sources.
RADPLIM = K ·
ICC
⎠
Where:
K
The over-current protection threshold is user pro-
grammable and independent from the constant
charge current setting. The set resistor RADPLIM is
connected between the ADPLIM pin and ground to
program the ADP power path current limit up to
1.6A. The set resistor RUSBLIM is connected
between the USBLIM pin and ground to program
the USB power path current limit up to 900mA. For
both the ADP and USB charge paths, the pro-
grammed constant current fast charge level may
not exceed the respective ADPLIM and USBLIM
set points. Refer to Table 3 for the ADPLIM and
USBLIM programming resistor values.
= KI_LIM_ADP = 27800
VADPLIM = 2V
ICC = Fast Charge Constant Current
For the USB input mode:
V
⎛
⎝
⎞
⎠
USBLIM
RUSBLIM = K ·
ICC
Where:
K
K
= KI_LIM_USBH = 17600 (USBH)
= KI_LIM_USBL = 3500 (USBL)
VUSBLIM = 2V
ICC = Fast Charge Constant Current
26
3670.2007.02.1.1
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
All constants K and VADP/USBLIM are specified in the
Typical Characteristics section of this datasheet.
resistor for RT. To determine the actual operating
temperature window for the the NTC thermistor and
the TS pin, one must first specify the NTC thermis-
tor to be used, then refer to the thermistor datasheet
to determine its characteristics.
Over-Voltage Protection
An over-voltage event is defined as a condition
where the voltage on the BATS pin exceeds the
maximum battery charge voltage and is set by the
over-voltage protection threshold (VOVP). If an
over-voltage condition occurs, the AAT3670 charge
control will shutdown the device until voltage on the
BATS pin drops below the over-voltage protection
threshold (VOVP). The AAT3670 will resume normal
charging operation once the battery over-voltage
condition is removed. During an over-voltage
event, the STAT2 LED will report a system fault.
The internal battery temperature sensing system is
comprised of two comparators which establish a
voltage window for safe operation. The thresholds
for the TS operating window are bounded by the
TS1 and TS2 specifications. Referring to the elec-
trical characteristics table in this datasheet, the TS1
threshold = 0.30 · VVTS and the TS2 threshold =
0.72 · VVTS. The VTS pin is capable of sourcing up
to 2mA.
Over-Temperature Shutdown
VTS
The AAT3670 has a thermal protection control cir-
cuit which will shut down charging functions should
the internal die temperature exceed the preset
thermal limit threshold.
0.72 · VVTS
RT
-
TS
Battery Cold Fault
Battery Hot Fault
+
-
Battery Temperature Fault Monitoring
In the event of a battery over-temperature condition,
the charge control will turn off the internal charge
path regulation device and report the fault condition
via the STAT2 display LED. After the system recov-
ers from a temperature fault, the device will resume
charging operation. The AAT3670 checks battery
temperature before starting the charge cycle, as
well as during all stages of charging.
RNTC
T
+
0.30 · VVTS
Figure 5: Battery Temperature Sense Circuit.
Typically, batteries employ the use of a negative
temperature coefficient (NTC) thermistor that is
integrated into the battery package. Most com-
monly used NTC thermistors used in battery packs
are approximately 10kΩ at room temperature
(25°C). However, the AAT3670 TS pin, in conjunc-
tion with the VTS pin, permits the use of almost any
value of NTC thermistor.
VTS
RT
0.72V
-
TS
Battery Cold Fault
Battery Hot Fault
+
There are two pins associated with the battery tem-
perature sensing function, TS and VTS. The battery
pack thermistor should be connected between the
TS pin and ground. The VTS pin is provided to allow
the user to program battery temperature sense
thresholds depending upon the value of the NTC
thermistor used in a given battery pack. A resistor
(RT) connected between the VTS pin and the TS pin
will set a bias for the NTC thermistor function. The
TS function has been designed such that a default
NTC thermistor value of 10kΩ will then require a 10k
RADJ
-
0.30V
+
RNTC
T
Figure 6: Battery Temperature Sense Circuit
with Externally Adjusted Window Threshold.
3670.2007.02.1.1
27
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
If the use of the battery temperature sense function
is not required, it may be disabled by disconnecting
the VTS pin from the TS pin and terminating the TS
pin to ground. The VTS pin can be left floating.
ommended to exceed 8mA for driving an individual
status LED. The required ballast resistor value can
be estimated using the following formulas:
For connection to the adapter supply:
Battery Charge Status Indication
The AAT3670 indicates the status of the battery
under charge using two status LED driver outputs.
These two LEDs can indicate simple functions
such as no battery charge activity, battery charg-
ing, charge complete and charge fault.
(VADP - VF(LED)
ILED(STAT1/2)
)
RB(STAT1/2)
=
Eq. 3:
Example: RB(STAT1) = (5.5V - 2.0V) 2mA = 1.75kΩ
Note: Red LED forward voltage (VF) is typically
2.0V @ 2mA.
Status Indicator Display
System charging status may be displayed using
one or two LEDs in conjunction with the STAT1 and
STAT2 pins on the AAT3670. These two pins are
simple switches to connect the status LED cath-
odes to ground. It is not necessary to use both dis-
play LEDs if a user simply wants to have a single
lamp to show "charging" or "not charging". This can
be accomplished by using the STAT1 pin and a sin-
gle LED. Using two LEDs and both STAT pins sim-
ply gives the user more information for the various
charging states. Refer to Table 4 for LED display
definitions.
For connection to the USB supply:
(VUSB - VF(LED)
ILED(STAT1/2)
)
RB(STAT1/2)
=
Eq. 4:
Example: RB(STAT2) = (5.0V - 3.2V) 2mA = 900Ω
Note: Green LED forward voltage (VF) is typically
3.2V @ 2mA.
For connection to the BAT supply:
The LED anodes should be connected to USB, ADP,
BAT, or OUT depending upon the system design
requirements. The LEDs should be biased with as
little current as necessary to create reasonable illu-
mination. A ballast resistor should be placed
between the status LED cathodes and the STAT1/2
pins. LED current consumption will add to the over
thermal power budget for the device package, hence
it is good reason to keep the LED drive current to a
minimum. 2mA should be sufficient to drive most
common low cost green or red LEDs. It is not rec-
(VBAT - VF(LED)
ILED(STAT1/2)
)
RB(STAT1/2)
=
Eq. 5:
Example: RB(STAT2) = (3.6V - 3.2V) 2mA = 200Ω
Note: Green LED forward voltage (VF) is typically
3.2V @ 2mA.
Event Description
STAT1
End of Charge (TERM Current Reached in CVM), Battery OV, Timeout, or Charge Disabled
No Battery (With Charge Enabled)
OFF
Flash (1Hz, 40% duty)
ON
Battery Charging (Including Suspended Charging Due to Battery OT/UT, or Device OT )
Event Description
STAT2
Charge Disabled, No Battery, End of Charge, or Charging Without Faults
Faults (Battery OV/OT/UT, or Device OT) or Timeout
OFF
ON
Table 4: LED Status Indicator (STATx Pulled Up to a Voltage Source with Resistors and LED).
28
3670.2007.02.1.1
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
No Battery Present Indication
First, the maximum power dissipation for a given
situation should the calculated:
If the AAT3670 charger IC is powered and enabled
from either the ADP or USB input, yet no battery is
connected to the BAT and BATS pins, the STAT1
LED will flash at a 1Hz rate with an approximate
40% duty cycle when a 10µF capacitor is connect-
ed between the BAT pin and ground. The flash rate
of the STAT1 LED can be adjusted by changing the
value of the battery output (BAT pin) capacitor. If
the capacitor value is increased above 20µF, the
no battery detect flashing function will be defeated.
Eq. 7: PD = [(VIN - VBAT) · ICC + (VIN · IOP) + (IOUT2 · RDS(ON)
)
Where:
PD
= Total power dissipation by the device
VIN
= either VADP or VUSB, depending on which
mode is selected
The flash rate of the no battery detect function may
be approximated by the following equation:
VBAT
ICC
= Battery voltage as seen at the BAT pin
= Maximum constant fast charge current
programmed for the application
I · T
V
IOP
= Quiescent current consumed by the
charger IC for normal operation
C =
Eq. 6:
IOUT
= Load current to system from the OUT pin
Where:
C = Capacitor value
RDS(ON) = On-resistance of load switch between
ADP or USB and OUT
I = Start up source current from the BAT pin = 5µA
Next, the maximum operating ambient temperature
for a given application can be estimated based on
the thermal resistance of the 4x4 QFN package
when sufficiently mounted to a PCB layout and the
internal thermal loop temperature threshold.
V = Difference voltage between the end of charge
voltage and the battery recharge threshold =
0.2V
T = Rate of LED flashing in seconds
Eq. 8: TA = TJ - (θJA · PD)
Thermal Considerations
The AAT3670 is available in a 4x4mm 24-pin QFN
package which can provide up to 2.0W of power
dissipation when it is properly bonded to a printed
circuit board, but can achieve a maximum thermal
resistance of 37°C/W with printed circuit board
enhancement. Many considerations should be
taken into account when designing the printed cir-
cuit board layout as well as the placement of the
charger IC package in proximity to other heat gen-
erating devices in a given application design. The
ambient temperature around the charger IC will
also have an effect on the thermal limits of a bat-
tery charging application. The maximum limits that
can be expected for a given ambient condition can
be estimated by the following discussion:
Where:
TA = Ambient temperature in °C
TJ = Maximum device junction temperature below
the thermal loop threshold
PD = Total power dissipation by the device
θJA = Package thermal resistance in °C/W
3670.2007.02.1.1
29
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
Example:
Capacitor Selection
For an application where the fast charge current for
the adapter mode is set to 1A, VADP = 5.0V, and the
worst-case battery voltage at 3.0V with the system
load disabled, what is the maximum ambient temper-
ature where the thermal limiting will become active?
Input Capacitor
In general, it is good design practice to place a
decoupling capacitor between the ADP and USB
pins and ground. An input capacitor in the range of
1µF to 22µF is recommended. If the source supply
is unregulated, it may be necessary to increase the
capacitance to keep the input voltage above the
under-voltage lockout threshold during device
enable and when battery charging is initiated.
Given:
VADP = 5.0V
VBAT = 3.0V
ICC = 1A
If the AAT3670 adapter input is to be used in a sys-
tem with an external power supply source, such as
a typical AC-to-DC wall adapter, then a CIN capac-
itor in the range of 10µF should be used. A larger
input capacitor in this application will minimize
switching or power bounce effects when the power
supply is "hot plugged" in. Likewise, a 10µF or
greater input capacitor is recommended for the
USB input to help buffer the effects of USB source
power switching, noise and input cable impedance.
IOP = 0.75mA
TJ = 110°C
θ
JA = 37°C/W
IOUT = 0
RDS(ON) = 0.4Ω
Using Equation 7, calculate the device power dissi-
pation for the stated condition:
Output Capacitor
The AAT3670 only requires a 1µF ceramic capaci-
tor on the BAT pin to maintain circuit stability. This
value should be increased to 10µF or more if the
battery connection is made any distance from the
charger output. If the AAT3670 is to be used in
applications where the battery can be removed
from the charger, such as with the case with desk-
top charging cradles, an output capacitor greater
than 10µF, but less than 20µF, may be required to
retard the device from cycling on and off when no
battery is present.
PD = (5.0V - 3.0V)(1A) + (5.0V · 0.75mA) + (02 · 0.4Ω)
Eq. 9:
= 2.00375W
The maximum ambient temperature before the
AAT3670 thermal loop becomes active can now be
calculated using Equation 8:
Eq. 10:
TA = 110°C - (37°C/W · 2.00375W)
= 35.86°C
Printed Circuit Board Layout
Considerations
Therefore, under the stated conditions for this
worst-case power dissipation example, the
AAT3670 will enter the thermal loop and lower the
fast charge constant current when the ambient
operating temperature rises above 35.86°C.
For the best results, it is recommended to physically
place the battery pack as close as possible to the
AAT3670 BAT pin as possible. To minimize voltage
drops on the PCB, keep the high current carrying
traces adequately wide. For maximum power dissi-
pation of the AAT3670 QFN package, the metal sub-
strate should be solder bonded to the board. It is
also recommended to maximize the substrate con-
tact to the PCB ground plane layer to further increase
local heat dissipation. Refer to the AAT3670 evalua-
tion board for a good layout example.
30
3670.2007.02.1.1
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
Ordering Information
Package
Marking1
Part Number (Tape and Reel)2
AAT3670ISK-4.2-T1
QFN44-24
TFXYY
All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means
semiconductor products that are in compliance with current RoHS standards, including
the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more
information, please visit our website at http://www.analogictech.com/pbfree.
Package Information3
QFN44-24
Pin 1 Identification
0.305 0.075
Pin 1 Dot By Marking
19
24
18
1
R0.030Max
13
6
12
7
4.000 0.050
2.7 0.05
Top View
Bottom View
0.214 0.036
Side View
All dimensions in millimeters.
1. XYY = assembly and date code.
2. Sample stock is generally held on part numbers listed in BOLD.
3. The leadless package family, which includes QFN, TQFN, DFN, TDFN and STDFN, has exposed copper (unplated) at the end of the
lead terminals due to the manufacturing process. A solder fillet at the exposed copper edge cannot be guaranteed and is not required
to ensure a proper bottom solder connection.
3670.2007.02.1.1
31
AAT3670
1.6A Dynamic Battery Charger
and Power Manager
© Advanced Analogic Technologies, Inc.
AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights,
or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice.
Customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold sub-
ject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. AnalogicTech
warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with AnalogicTech’s standard warranty. Testing and other quality con-
trol techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed.
AnalogicTech and the AnalogicTech logo are trademarks of Advanced Analogic Technologies Incorporated. All other brand and product names appearing in this document are regis-
tered trademarks or trademarks of their respective holders.
Advanced Analogic Technologies, Inc.
830 E. Arques Avenue, Sunnyvale, CA 94085
Phone (408) 737-4600
Fax (408) 737-4611
32
3670.2007.02.1.1
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