Analogic AAT3663 1a linear li-ion battery charger for single and dual cell application Datasheet

AAT3663
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
General Description
Features
The AAT3663 BatteryManager™ is a member of
AnalogicTech’s Total Power Management IC™
family. This device is an integrated single/dual cell
Lithium-Ion (Li-Ion) / polymer battery charger IC
designed to operate from USB ports or an AC
adapter inputs up to an input voltage of 13.2V.
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AAT3663 precisely regulates battery charge voltage and current for 4.2V and 8.4V Li-Ion battery
cells. The battery charging current is user programmed up to 1A by an external resistor.
Battery charge state is continuously monitored for
fault conditions. A Digital Thermal Loop Control
maintains the maximum possible battery charging
current for the optimum set of input to output power
dissipation and ambient temperature conditions. In
the event of an over-current, over-voltage, shortcircuit, or over-temperature fault condition, the
device will automatically shut down, thus protecting
the charger and the battery under charge.
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Two status monitor output pins are provided to indicate the battery charge status by directly driving
external LEDs. Additionally, an open-drain powersource detection output (ADPP#) is provided to
report presence of an input power supply
BatteryManager™
4.0V ~ 13.2V Input Voltage Range
Compatible with USB or AC Adapter Sources
Programmable Fast Charge Current from
100mA to 1A
Programmable Charge Termination Current
Digital Thermal Loop Charge Reduction
Less Than 0.4µA Battery Leakage Current
Programming Charge Timer
Battery Temperature Sensing
Battery Temp Sense Open Circuit Detection
Automatic Recharge Sequencing
Automatic Trickle Charge for Battery
Pre-Conditioning
Automatic Charge Termination
Shutdown/Sleep Mode
Less than 1µA Shutdown Current
Over-Voltage and Over-Current Protection
Power On Reset and Soft Start
3x3mm 14-pin TDFN Package
Applications
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•
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The AAT3663 is available in a thermally enhanced,
space-saving, 14-pin 3x3 mm TDFN package and
is specified for operation over the -40°C to +85°C
temperature range.
Bluetooth™ Headset
Cell Phones
Digital Still Cameras
MP3 Players
Personal Data Assistants (PDAs)
Other Li-Ion Battery Powered Devices
Typical Application
ON/OFF
EN BATS
VIN
IN
BATT+
BAT
10μF
AAT3663
BATT-TEMP
STAT1
TS
STAT2
TERM
ISET
ADPP#
GND
Battery
Pack
CT
CT
3663.2007.10.1.0
RSET
R TERM
1
AAT3663
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
Pin Description
Pin #
Symbol
Type
1
EN
I
2
CT
I
3
ISET
I
4
5
GND
TS
I/O
I/O
6
BATS
I
7
8, 9
10
BAT
IN
STAT1
O
I
O
11
STAT2
O
12
ADPP#
O
13
TERM
I
14
N/C
Function
Enable pin, Active high with internal pull-down. If not used, pull high to the IN pin to
continuously enable the charger IC when input power is applied.
Charge timer programming pin. A 0.1µF ceramic capacitor should be connected
between this pin and GND. Connect directly to GND to disable the timer function.
Charge current programming pin. Connect a resistor between this pin and GND to
program the constant fast charge current.
IC ground connection. Connect this pin to power ground.
Battery temperature sense input. Connect the Li-Ion battery pack NTC resistor terminal to this pin.
Battery voltage sense pin. Connect this pin directly to the positive battery terminal. If
this function is not used, connect to the BAT pin directly.
Battery charge output pin. Connect to the positive battery terminal.
Power supply input pin. Connect the input USB port or Adapter power source to this pin
Charge status pin, open-drain output. Connect the STAT1 LED with a series ballast
resistor between IN and this pin.
Charge status pin, open-drain output. Connect the STAT2 LED with a series ballast
resistor between IN and this pin.
Input supply power-good status pin, open-drain output. Connect the ADPP# status
LED with a series ballast resistor between IN and this pin.
Charge termination current programming input pin. Connect a resistor between this
pin and GND to program the charge termination current. When TERM is open, the
termination current is 10% (default sertting) of the set maximum charge current.
No connection.
Pin Configuration
TDFN33-14
(Top View)
EN
CT
ISET
GND
TS
BATS
BAT
2
1
14
2
13
3
12
4
11
5
10
6
9
7
8
N/C
TERM
ADPP#
STAT2
STAT1
IN
IN
3663.2007.10.1.0
AAT3663
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
Absolute Maximum Ratings1
Symbol
VIN
VN
VN
TJ
TLEAD
Description
IN Continuous Voltage
STAT1, STAT2, ADPP#, EN, BAT, BATS
TS, CT, TERM, ISET
Operating Junction Temperature Range
Maximum Soldering Temperature (at Leads)
Value
Units
-0.3 to 14
-0.3 to VIN + 0.3
-0.3 to 5.5
-40 to 150
300
V
V
V
°C
°C
Value
Units
50
2
°C/W
W
Thermal Information2
Symbol
θJA
PD
Description
Maximum Thermal Resistance (TDFN3x3)
Maximum Power Dissipation
AAT3663 Feature Options
Product
Number of Battery Cells
Battery Temperature Sense
AAT3663-4.2-1
AAT3663-4.2-2
AAT3663-8.4-1
AAT3663-8.4-2
Single
Single
Dual
Dual
For Use With Any NTC Thermistor
For Use With 10kΩ NTC Thermistor
For Use With Any NTC Thermistor
For Use With 10kΩ NTC Thermistor
1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions 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.
3663.2007.10.1.0
3
AAT3663
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
Electrical Characteristics
VIN = 5V, TA = -25 to +85°C; Unless otherwise noted, typical values are at TA = 25°C
Symbol
Description
Conditions
Min
Rising Edge
4.0
3
Operation
VIN
Input Voltage Range
Under Voltage Lockout Threshold
VUVLO
UVLO Hysteresis
Adapter Present Indicator Threshold
VADPP_TH
Voltage, VIN – VBAT
IOP
Operating Current
ISHUTDOWN Shutdown Current
ILEAKAGE
Leakage Current from BAT Pin
ENLEAKAGE EN Pin Leakage
Voltage Regulation
VBAT_EOC
ΔVBAT_EOC/
VBAT_EOC
VMIN
End of Charge Voltage Regulation
VIN > VUVLO
Charge Current = 100mA
VBAT = 4.25V, EN = GND
VBAT = 4V, IN = Open
VEN = 5V
AAT3663-4.2
AAT3663-8.4
4.158
8.316
AAT3663-4.2
AAT3663-8.4
2.5
5.0
Battery Recharge Voltage Threshold
Current Regulation
ICC_RANGE Charge Current Programmable Range
VISET
KISET
VTERM
ICH_TRK
ICH_TERM
4
V
V
mV
50
100
mV
0.35
0.4
0.4
0.6
1
1
2
mA
µA
µA
µA
4.2
8.4
4.242
8.484
2.6
5.2
100
Constant-Current Mode
Charge Current
RISET = 1.74KΩ (for 1A),
VBAT = 3.6V
RISET = 17.8KΩ (for 0.1A),
VBAT = 3.6V
ISET Pin Voltage
Charge Current Set Factor:
ICH_CC/ISET
TERM Pin Voltage
Trickle-Charge Current
Constant Current Mode,
VBAT = 3.6V
RTERM = 40kΩ
Charge Termination Current Threshold
TERM pin open
RTERM = 13.3 kΩ,
ICH_CC ≥ 800mA
Charging Devices
RDS(ON)
Charging Transistor ON Resistance
Logic Control / Protection
Input High Threshold
VEN
Input Low Threshold
VSTAT
Output Low Voltage
ISTAT
STAT Pin Current Sink Capability
13.2
4
2.7
5.4
V
V
1000
900
1000
1100
80
100
120
mA
mA
2
V
900
5
5
0.6
10
10
15
15
% ICH_CC
% ICH_CC
8
10
12
% ICH_CC
330
500
mΩ
VIN = 5V
V
1.6
STAT Pin Sinks 4mA
V
%
VBAT_EOC
- 0.1
VBAT_EOC
- 0.2
AAT3663-8.4
ICH_CC
Units
0.5
AAT3663-4.2
VRCH
Max
150
End of Charge Voltage Accuracy
Preconditioning Voltage Threshold
Typ
0.4
0.4
8
V
V
mA
3663.2007.10.1.0
AAT3663
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
Electrical Characteristics
VIN = 5V, TA = -25 to +85°C; Unless otherwise noted, typical values are at TA = 25°C
Symbol
Description
Logic Control / Protection
VADDP#
Output Low Voltage
IADPP#
ADDP# Current Sink Capability
VOVP
Over-Voltage Protection Threshold
VOCP
TK
TV
ITS
Over-Current Protection Threshold
Trickle Charging Time-Out
Trickle and Constant Current
Mode Time-Out
Constant Voltage Mode Time-Out
Current Source from TS Pin
TS1
TS Hot Temperature Fault
TS2
TS Cold Temperature Fault
VTS1
High Temperature Threshold
VTS2
Low Temperature Threshold
TC
TLOOP_IN
TLOOP_OUT
TREG
TSHDN
3663.2007.10.1.0
Conditions
Typ
ADPP# Pin Sinks 4mA
AAT3663-4.2
AAT3663-8.4
Max
Units
0.4
8
V
mA
CT = 100nF, VIN = 5V
4.4
8.8
105
TC/8
%VCS
Hour
CT = 100nF, VIN = 5V
3
Hour
CT = 100nF, VIN = 5V
AAT3663-2 Only
Threshold, AAT3663-2 Only
Hysteresis, AAT3663-2 Only
Threshold, AAT3663-2 Only
Hysteresis, AAT3663-2 Only
Threshold, AAT3663-1 Only
Hysteresis, AAT3663-1 Only
Threshold, AAT3663-1 Only
Hysteresis, AAT3663-1 Only
Digital Thermal Loop Entering
Threshold
Digital Thermal Loop Exiting
Threshold
Digital Thermal Loop Regulation
Over-Temperature Shutdown
Min
Threshold
Hysteresis
71
316
2.30
29.1
58.2
3
75
331
25
2.39
25
30
2
60
2
V
79
346
2.48
30.9
61.8
Hour
µA
mV
mV
%VIN
%VIN
115
ºC
85
ºC
100
140
15
ºC
ºC
5
AAT3663
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
Typical Characteristics
Constant Charging Current
vs. Set Resistor Values
Operating Current (µA)
2000
1800
1600
1400
Constant Current Mode
1200
1000
800
600
400
200
Preconditioning Mode
0
1
10
100
Constant Charge Current (mA)
Operating Current vs ISET Resistor
10000
1000
100
10
1
1
10
RSET (kΩ
Ω)
100
RSET (kΩ
Ω)
End of Charge Voltage Accuracy vs. Input Voltage
End of Charge Voltage vs. Temperature
0.100
4.220
0.075
4.215
Battery Voltage (V)
End of Charge
Voltage Accuracy (%)
(VBAT_EOC = 4.2V)
0.050
0.025
0.000
-0.025
-0.050
4.210
4.205
4.200
4.195
4.190
4.185
-0.075
4.180
-0.100
4
5
6
7
8
9
10
11
12
13
-40
14
-15
Input Voltage (V)
35
60
85
Recharge Voltage vs. Temperature
(VIN = 5V; RSET = 8.87kΩ
Ω)
4.120
4.14
4.115
4.13
Battery Voltage (V)
Battery Voltage (V)
Recharge Threshold Voltage vs. Input Voltage
4.110
4.105
4.100
4.095
4.090
4.12
4.11
4.10
4.09
4.08
4.07
4.085
4.06
4.080
4
5
6
7
8
9
10
Input Voltage (V)
6
10
Temperature (°C)
11
12
13
14
-40
-15
10
35
60
85
Temperature (ºC)
3663.2007.10.1.0
AAT3663
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
Typical Characteristics
Constant Charging Current vs. VBAT
Constant Charging Current vs. Battery Voltage
(RSET = 8.87kΩ
Ω)
1200
VIN = 13.2V
210
1.78K
1000
180
VIN = 12V
VIN = 9.5V
150
ICH (mA)
Charging Current (mA)
240
VIN = 7.5V
120
VIN = 5V
90
2.21K
800
600
3.57K
400
60
8.87K
200
30
0
2.5
0
2.3
2.5
2.7
2.9
3.1
3.3
3.5
3.7
3.9
4.1
4.3
2.7
2.9
VBAT (V)
3.5
3.7
3.9
4.1
4.3
Preconditioning Threshold Voltage vs. Temperature
2.70
2.70
2.68
2.68
Battery Voltage (V)
Battery Voltage (V)
3.3
Battery Voltage (V)
Preconditioning Threshold Voltage vs. Input Voltage
2.66
2.64
2.62
2.60
2.58
2.56
2.54
2.66
2.64
2.62
2.60
2.58
2.56
2.54
2.52
2.52
2.50
2.50
4
5
6
7
8
9
10
11
12
13
14
-40
-15
Input Voltage (V)
10
35
60
85
Temperature (°C)
Preconditioning Charge Current
vs. Input Voltage
Temperature Sense Output Current
vs. Temperature
120
80
79
RSET = 1.78kΩ
100
78
RSET = 2.21kΩ
80
60
77
ITS (µA)
ICH_TRK (mA)
3.1
RSET = 3.57kΩ
40
76
75
74
73
RSET = 8.87kΩ
20
72
71
70
0
4
5
6
7
8
9
10
11
Input Voltage (V)
3663.2007.10.1.0
12
13
14
-40
-15
10
35
60
85
Temperature (°C)
7
AAT3663
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
Typical Characteristics
Constant Charge Current vs. Input Voltage
Shutdown Current vs. Input Voltage
2.40
Shutdown Current (µA)
Charge Current (mA)
240
230
VBAT = 3.5V
VBAT = 3V
220
210
200
190
VBAT = 3.9V
180
170
VBAT = 4.1V
160
2.10
85°C
1.80
25°C
1.50
1.20
0.90
-40°C
0.60
0.30
0.00
4
5
6
7
8
10
11
12
13
14
4
5
6
7
Input Voltage (V)
1.60
1.40
1.40
1.20
VEN(L) (V)
VEN(H) (V)
10
11
12
13
14
Input Low Threshold vs. Input Voltage
1.60
-40°C
1.00
0.80
25°C
9
Input Voltage (V)
Input High Threshold vs. Input Voltage
0.60
8
1.20
-40°C
1.00
0.80
0.60
85°C
0.40
25°C
85°C
0.40
4
5
6
7
8
9
10
11
12
13
4
14
5
6
Input Voltage (V)
7
8
9
10
11
12
13
14
Input Voltage (V)
Charging Transistor On Resistance
vs. Input Voltage
Termination Current to Constant Current
Ratio (%) vs. Termination Resistance
600
50
45
ICH_TERM/ICH_CC (%)
500
RDS(ON) (mΩ
Ω)
85°C
400
300
200
100
-40°C
25°C
35
30
25
20
15
10
5
0
0
4.0
4.4
4.8
5.2
5.6
6.0
6.4
6.8
Input Voltage (V)
8
40
7.2
7.6
8.0
8.4
0
10
20
30
40
50
60
RTERM (kΩ
Ω)
3663.2007.10.1.0
AAT3663
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
Typical Characteristics
CT Pin Capacitance vs. Counter Timeout
1.0
Capacitance (µF)
0.9
0.8
0.7
Preconditioning Timeout
0.6
0.5
0.4
Preconditioning + Constant
Current Timeout or Constant
Voltage Timeout
0.3
0.2
0.1
0.0
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Timeout (h)
3663.2007.10.1.0
9
AAT3663
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
Functional Block Diagram
Reverse Blocking
IN
BAT
CV/
Precharge
Current
Compare
ISET
Constant
Current
TERM
ADPP#
Charge
Control
UVLO
Over-Temp
Protect
Power
Detection
BATS
Charge
Status
Thermal
Loop
STAT 1
STAT 2
EN
75μA
AAT3663-2 Only
Watchdog
Timer
TS
CT
Window Comparator
GND
Functional Description
The AAT3663 is a high performance battery charger
designed to charge single/dual cell Lithium-Ion or
Lithium-Polymer batteries with up to 1000mA of current
from an external power source. It is a highly integrated
stand-alone charging solution, with the least external
components required for complete functionality.
The AAT3663 precisely regulates end of charge battery voltage and current for single cell 4.2V and dual
cell 8.4V lithium-ion/polymer battery with a programmable constant current range from 100mA to 1A for
fast charging applications. The system has a default
charge termination current set to 10 percent of the programmed fast charge constant. The charge termination current may also be user programmed by an
external resistor.
During battery charging, the device temperature will
rise. In some cases with adapter (ADP) charging, the
power dissipation in the charge regulation pass device
may cause the junction temperature to rise and
approach the internal thermal shutdown threshold.
Excessive power dissipation is caused by the high
input adapter voltage versus the low output battery cell
voltage difference at a given constant charge current.
10
In the event of an internal over-temperature condition
caused by excessive ambient operating temperature
or excessive power dissipation conditions, the
AAT3663 enables a digitally controlled thermal loop
system that will reduce the charging current to prevent
thermal shutdown. The digital thermal loop will maintain the maximum possible battery charging current for
a 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 normal operation when
the power dissipation or over-temperature conditions
are removed.
In the event of an over-voltage, over-current or overtemperature false condition beyond the limits of the
digital thermal loop system, the device will automatically shut down, thus protecting the charging device,
control system, and the battery under charge.
AAT3663 provides two status monitor pins, STAT1 and
STAT2. These pins are open drain MOSFET switches
intended to directly drive external LEDs to indicate the
battery charging state. A third status pin is prided to
3663.2007.10.1.0
AAT3663
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
indicate the presence of power on the input supply pin.
This open drain MOSFET switch may be used to either
power a display LED or to alert a system microcontroller for the presence on input power.
Battery Charging Operation
Figure 1 illustrates the entire battery charging profile
and operation, which consists of three phases:
Constant Current Charging
Trickle charging continues until the battery voltage
reaches the VMIN threshold. At this point, the AAT3663
begins constant-current fast charging. The current
level for this mode is programmed using a single resistor from the ISET pin to ground. Programmed current
can be set at a minimum 100mA up to a maximum 1A.
Constant Voltage Charging
1. Preconditioning (Trickle) Charge
2. Constant Current Charge
3. Constant Voltage Charge
When power is initially applied or when a battery pack
is connected to the BAT pin, battery charging commences after the AAT3663 checks several conditions
in order to maintain a safe charging environment. The
input supply must be above the minimum operating
voltage (UVLO) and the enable pin must be high (internally pulled down). When the battery is connected to
the BAT pin the AAT3663 checks the condition of the
battery and determines which charging mode to apply.
Battery Preconditioning
If the battery voltage is below VMIN, the AAT3663 begins
battery trickle charging by charging at 10% of the programmed constant-current. For example, if the programmed current is 500mA, then the trickle charge current is 50mA. Trickle charging is a recommended safety precaution for a deeply discharged cell and maximizes the charge cycle life of the battery. In addition,
charger IC power dissipation for the internal series pass
MOSFET is minimized when the input-output voltage
differential is at its highest. This in turn allows the
charging operation to commence over wider thermal
and input to output voltage differential conditions.
Preconditioning
Trickle Charge
Phase
Constant current charging continues until such time
that the battery voltage reaches the voltage regulation
point VBAT_REG. When the battery voltage reaches
VBAT_REG, the AAT3663 will transition to the constantvoltage mode. The regulation voltage is factory programmed to a nominal 4.2V for the AAT3663-4.2
option and to 8.4V for the AAT3663-8.4 option. Under
default conditions with the TERM pin not connected
(open circuit), constant voltage charging will continue
until the charge current has reduced to 10% of the programmed current. Placing a resistor between the
TERM pin and ground allows the user to program a
desired termination current.
After the charge cycle is complete, the AAT3663 turns
off the series pass device and automatically goes into
a power saving sleep mode. During this time the series
pass device will block current in both directions therefore preventing the battery discharging through the IC.
The AAT3663 will remain in sleep mode, until either the
battery terminal voltage drops below the VRCH threshold, the charger EN pin is recycled or the charging
power source is reconnected. In all cases the
AAT3663 will monitor all battery parameters and
resume charging in the appropriate mode.
Constant Current
Charge Phase
Constant Voltage
Charge Phase
Charge Complete Voltage
I = Max CC
Regulated Current
Constant Current Mode
Voltage Threshold
Trickle Charge and
Termination Threshold
I = CC / 10
Figure 1: Current and Voltage Profile During Charging Phases.
3663.2007.10.1.0
11
AAT3663
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
System Operation Flow Chart
ADP
Voltage
Power
Input
S
Voltage
ADP > VADPP
VIN>VUVLO
Power
On
Sleep
Sleep
Reset
Mode
Mode
No
Yes
Enable
Power
Select
EN=HIGH
No
FAULT
Shut
ShutDown
Down
STAT1=Off
Mode
STAT2=Off
Mode
Yes
Yes
Fault
Fault
Condition Monitoring
Power
Select
OV, OT,
V TS1<TS<VTS 2
No
Yes
Shut
Shut
Down
Down
Shut
Down
Mode
Mode
Mode
Expire
VBAT <VMIN or
Power Select
or
<V
BAT_REG
IBAT >ITERM
No
Charger
Shut
Down
ShutTimer
Down
Control
Mode
Mode
Preconditioning
Test
V
VMIN >V
>V
BAT
MIN
Yes
Preconditioning
Shut
ShutDown
Down
Set
(Trickle
Charge)
Mode
Mode
BAT
No
No
Recharge
Test
VRCH >V BAT
Yes
Current Phase Test
VIN > VBAT_EOC
Yes
Constant
Shut Current
Down
Shut Down
Charge
Mode
Mode
Mode
VCH>VBAT
No
Device
Temp
. No
Device
Temp.
Monitor
Monitor
TTJ >115°C
J >110° C
Yes
Thermal Loop
Shut
Down
Shut
Down
Current
Reduction
In C.C.
Mode
Mode
Mode
Voltage Phase Test
IBAT >ITERM
IBAT> MI IN
Yes
Constant
Shut
Down
ShutVoltage
Down
Charge
Mode
Mode
Mode
Mode
No
Charge
Charge
Charge
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3663.2007.10.1.0
AAT3663
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
Application Information
Adapter or USB Power Input
Constant current charge levels up to 1A may be
programmed by the user when powered from a sufficient input power source. The AAT3663 will operate over an input voltage range from 4.0V to 13.2V.
The low input voltage capability of the AAT3663
permits charging single cell Li-Ion/Poly batteries
from USB ports and lower voltage input power
sources. The high 13.2V input rating of this device
allows for the use of a wide range of input power
sources for both single and dual cell Li-Ion/Poly
applications.
Adapter Input Charge Inhibit and
Resume
The AAT3663 has an under-voltage lockout (UVLO)
and power on reset feature so that if the input supply to the IN pin drops below the UVLO threshold,
the charger will suspend charging and shut down.
When power is reapplied to the IN 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.
Battery Connection and Battery Voltage
Sensing
Battery Connection
A single or dual cell Li-Ion/Polymer battery should
be connected between the BAT pin and ground.
Battery Voltage Sensing
The BATS pin is provided to employ an accurate
voltage sensing capability to measure the positive
terminal voltage at the battery cell being charged.
This function reduces measured battery cell voltage error between the battery terminal and the
charge control IC. The AAT3663 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 concern of the
3663.2007.10.1.0
battery sense function inadvertently becoming an
open circuit, the BATS pin may be terminated to the
BAT pin using a 10kΩ resistor. Under normal operation, the connection to the battery terminal will be
close to 0Ω; if the BATS connection becomes an
open circuit, the 10kΩ resistor will provide feedback to the BATS pin from the BAT connection with
a voltage sensing accuracy loss of 1mV or less.
Enable (EN)
EN is a logic input (active high) to enable the
charger, this function is internally pulled down to
ground. When the device is initially enabled or if
the EN pin is cycled low and then 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 battery voltage on the BATS pin.
Programming Charge Current
The constant current mode charge level is user programmed with a set resistor (RSET) connected
between the ISET pin and ground. The accuracy of
the constant charge current, as well as the preconditioning trickle charge current, is dominated by the
tolerance of the set resistor used. For this reason, a
1% tolerance metal film resistor is recommended for
the set resistor function. The constant charge current levels from 100mA to 1A may be set by selecting the appropriate resistor value from Table 1.
Constant Charging
Current (mA)
Set Resistor
Value (kΩ)
100
200
300
400
500
600
700
800
900
1000
17.8
8.87
5.9
4.42
3.57
2.94
2.55
2.21
1.96
1.78
Table 1: RSET Values.
13
AAT3663
50
10000
45
ICH_TERM/ICH_CC (%)
CC Mode Charge Current (mA)
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
1000
100
10
40
35
30
25
20
15
10
5
0
1
1
10
0
100
10
If the desired charge current level is not listed in
Table 1, the RSET resistor value can be found in
Figure 2 and calculated by the following equation:
RSET = K ·
⎛VISET⎞
⎝ ICC ⎠
Programmable Charge Termination
Current
The AAT3663 is designed with a default charge termination current set to 10 percent of the programmed fast charge constant current level. The
charge termination current (ICH_TERM) may also be
user programmed to a level other than 10% of the
set fast charge current by connecting a set resistor
(RTERM) between the TERM pin and ground.
When the charge current under the constant voltage charging mode drops to the charge termination
threshold the device halts charging and goes into
a sleep mode. The charger will remain in the sleep
mode until the battery voltage as sensed by the
BATS pin decreases to a level below the battery
recharge voltage threshold (VRCH). Charge termination current levels based on a percentage of the
programmed fast charge current are shown in
Figure 3.
14
40
50
60
Figure 3: Charge Termination Current (% Value
of the Programmed Fast Charge Current) vs.
RTERM Resistance.
If the desired charge termination current set resistor
(RTERM) value is not shown in Figure 3, the value
may be determined by the following equation:
ICH_TERM =
Where:
K = KI_SET = 900
VISET = 2V
ICC = Fast charge constant current
30
RTERM (kΩ
Ω)
RSET (kΩ
Ω)
Figure 2: Constant Charging Current vs. RSET
Resistor Values.
20
15µA · RTERM
· ICH_CC
2V
Where:
ICH_TERM = Charge termination current level
ICH_CC = Programmed fast charge constant current
level
RTERM = TERM resistor value
Battery Charge Status Indication
The AAT3663 indicates the status of the battery
under charge using three status LED driver outputs. These three LEDs can indicate simple functions such as input power present, no battery
charge activity, battery charging, charge complete
and charge fault.
Status Indicator Display
System charging status may be displayed using
one or two LEDs in conjunction with the STAT1 and
STAT2 pins on the AAT3663. These two pins are
simple open drain N-channel MOSFET switches to
connect the status LED cathodes to ground. It is
not necessary to use both display LEDs if a user
simply wants to have a single LED to show “charging” or “not charging”. This can be accomplished
3663.2007.10.1.0
AAT3663
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
by just using the STAT1 pin and a single LED.
Using two LEDs and both STAT pins simply gives
the user more information for the various charging
states. Refer to Table 2 for LED display definitions.
The LED anodes should be connected to the
charger power source input (IN pin).
Event Description
STAT1
STAT2
Charge enabled without battery
Battery charging
Charging completed
Fault
Flash1
ON
OFF
OFF
Flash1
OFF
ON
OFF
Table 2: LED Status Indicator Truth Table.
Input Power Present Indicator
The ADDP# pin provides an additional open drain
N-channel MOSFET switch to indicate the presence of power applied to the charger input (IN pin).
This function may either be used to control an addition status LED to give a visual indication when
input power is applied. This open drain output may
also be pulled high via a pull up resistor to provide
an active low signal to a system microcontroller to
indicate the presence of applied input power.
Status Display LED Biasing
The LED should be biased with as little current as
necessary to create reasonable illumination; therefore, a ballast 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 package, 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.
The required ballast resistor values can be estimated using the following formula:
RBALLAST =
(VIN - VF(LED))
ILED
Example:
RBALLAST =
(5.0V - 2.0V)
= 1.5kΩ
2mA
Note: Red LED forward voltage (VF) is typically
2.0V @ 2mA.
Digital Thermal Loop Control
Due to the integrated nature of the linear charging
control pass device for the adapter mode, a special
thermal loop control system has been employed to
maximize charging current under all operation conditions. The thermal management system measures the internal circuit die temperature and
reduces the fast charge current when the device
exceeds a preset internal temperature control
threshold. Once the thermal loop control becomes
active, the fast charge current is initially reduced by
a factor of 0.28. The initial thermal loop current can
be estimated by the following equation:
ITLOOP = ICH_CC · 0.28
The thermal loop control re-evaluates the circuit die
temperature every 1.5 seconds and adjusts the fast
charge current back up in small steps to the full fast
charge current level or until an equilibrium current
is discovered and maximized for the given ambient
temperature condition. The thermal loop controls
the system charge level; therefore, the AAT3663
will always provide the highest level of constant
current in the fast charge mode possible for any
given ambient temperature condition.
1. Flashing rate depends on output capacitance.
3663.2007.10.1.0
15
AAT3663
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
Protection Circuitry
Programmable Timer Function
The AAT3663 contains a watchdog timing circuit to
shut down charging functions in the event of a
defective battery cell not accepting a charge over a
preset period of time. 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 out a shutdown condition if the
trickle charge mode exceeds 25 minutes and a
combined trickle charge plus constant current
mode of 3 hours. When the device transitions to
the constant voltage mode, the timing counter is
reset and will time out after an additional 3 hours if
the charge current does not drop to the charge termination level.
The AAT3663 has a battery fault detector, which,
when used in conjunction with a 0.1μF capacitor on
the CT pin, outputs a 1Hz signal with 50% duty
cycle at the STAT1 pin in the event of a timeout
while in the trickle charge mode.
Mode
Time
Trickle Charge (TC) Time Out
Trickle Charge (TC) + Constant
Current (CC) Mode Time Out
Constant Voltage (CV) Mode Time Out
25 minutes
3 hours
3 hours
Table 3: Summary for a 0.1μF Ceramic
Capacitor Used for the Timing Capacitor.
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 timeout periods would be doubled.
If the programmable watchdog timer function is not
needed, it can be disabled by terminating the CT
pin to ground. The CT pin should not be left floating
or unterminated, as this will cause errors in the
internal timing control circuit. 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 physically located on the printed circuit board layout as close as possible to the
CT pin. Since the accuracy of the internal timer is
dominated by the capacitance value, a 10% tolerance or better ceramic capacitor is recommended.
16
Ceramic capacitor materials, such as X7R and X5R
types, are a good choice for this application.
Over-Voltage Protection
An over-voltage event is defined as a condition
where the voltage on the BAT pin exceeds the maximum battery charge voltage and is set by the overvoltage protection threshold (VOVP). If an over-voltage condition occurs, the AAT3663 charge control
will shut down the device until the voltage on the
BAT pin drops below VOVP. The AAT3663 will
resume normal charging operation after the overvoltage condition is removed. During an over-voltage event, the STAT LEDs will report a system fault.
Over-Temperature Shutdown
The AAT3663 has a thermal protection control circuit which will shut down charging functions once
the internal die temperature exceeds the over-temperature shutdown threshold. Once the internal die
temperature falls below the hysteresis, normal
operation will resume the previous charging state.
Battery Temperature Fault Monitoring
There are two AAT3663 temperature sense options,
The AAT3663-1 and AAT3663-2. The AAT3663-1
option allows of the use of any NTC resistor. For
ease of use, the AAT3663-2 option is factory set to
function with typical 10kΩ NTC resistors and eliminates the need for a resistor divider pull up to the
input power source.
Regardless of the AAT3663 option selected, the
internal system control checks battery temperature
before starting the charge cycle and continues to
monitor the battery temperature during all stages of
the charging cycle. This is accomplished by monitoring the voltage at the TS pin. In general, the system is intended for use with negative temperature
coefficient thermistors (NTC) which are typically
integrated into the battery package. The voltage on
the TS pin resulting from the resistive load and
applied current, should stay within a window
bounded by the TS1 and TS2 specification thresholds. Refer to the Electrical Characteristics table
for the TS1 and TS2 limits for a selected AAT3663
option. If the battery becomes too hot during
charge cycle due to an internal fault or excessive
charge current, the NTC thermistor will heat up and
reduce in value. This in turn will pull the TS pin
3663.2007.10.1.0
AAT3663
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
voltage below than the TS1 threshold, and indicate
a battery cell temperature fault. The charging
process will then be suspended until the over-temperature condition is removed, at which time
charging will resume. Conversely, if the battery
under charge is exposed to extreme cold ambient
temperature condition, the NTC thermistor may
increase in value and push the voltage on the TS
pin above the TS2 threshold. In such a case, the
charge cycle will be suspended and will not resume
until the cold fault condition is removed. Both TS1
and TS2 temperature fault conditions will be report
by the STAT1 and STAT2 LEDs.
AAT3663-2 Option
Most of the commonly used NTC thermistors in LiIon/Polymer battery packs are approximately 10kΩ
at room temperature (25°C). The AAT3663-2 TS
pin has been specifically designed to source 75µA
of current to the 10kΩ NTC thermistor. The applied
constant current source and fixed internal TS1 and
TS2 voltage thresholds eliminate the need for a
resistor divider on the TS pin. Simply connect the
10kΩ NTC resistor between the TS pin and ground.
If the TS function is not needed for the AAT3663-2,
it may be left open (not connected).
AAT3663-1 Option
the AAT3663-1 option utilizes an internal battery
temperature sensing system 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 electrical characteristics table
in this datasheet, the TS1 threshold = 0.30 · VIN and
the TS2 threshold = 0.6 · VIN. Refer to Figure 4 for
external resistor and NTC thermistor connections.
Thermal Considerations
The AAT3663 is offered in a 3x3mm TDFN package
which can provide up to 2.0W of power dissipation
when it is properly bonded to a printed circuit board
and has a maximum thermal resistance of 50°C/W.
Many considerations should be taken into account
when designing the printed circuit board layout, as
well as the placement of the charger IC package in
proximity to other heat generating devices in a given
application. The ambient temperature around the
charger IC will also have an effect on the thermal limits of the battery charging operation. The maximum
limits that can be expected for a given ambient condition can be estimated by the following discussion.
If the use of the battery temperature sense function
is not required, it may be disabled by terminating
the TS pin to IN and ground using a 10kΩ resistor
divider network. If circuit power dissipation is a
concern, the two terminating resistor values may
be increased to 100kΩ.
VIN
IN
RT
AAT3663-4.2-1 or AAT3663-8.4-1
0.6xV IN
Battery Cold Fault
TS
Battery
Pack
Battery Hot Fault
RNTC
T
0.30xVIN
Figure 4: External Resistor and NTC Thermistor Application Circuit.
3663.2007.10.1.0
17
AAT3663
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
First, the maximum power dissipation for a given situation should be calculated:
Where:
PD(MAX) =
(TJ - TA)
θJA
PD(MAX) = Maximum Power Dissipation (W)
θJA
= Package Thermal Resistance (°C/W)
TJ
= Thermal Loop Entering Threshold (ºC)
[115ºC]
TA
= Ambient Temperature (°C)
Figure 5 shows the relationship between maximum
power dissipation and ambient temperature of
AAT3663
2.50
PD(MAX) (W)
2.00
1.50
By substitution, we can derive the maximum
charge current before reaching the thermal limit
condition which will activate digital thermal loop
operation. The maximum charge current is the key
factor when designing battery charger applications.
In general, the worst case condition is when the greatest input to output voltage drop occurs across the
charger IC. Specifically when battery voltage is
charged up just above the preconditioning voltage
threshold and the charger enters into the constant
current fast charging mode. Under this condition, the
device will suffer the maximum possible power dissipation since both the voltage difference across the
device and the charge current will be at their respective maximums. Figure 6 shows the safe fast charge
current operating region for different ambient temperatures. Exceeding these limits will drive the charge
control into digital thermal loop operation. When
under digital thermal loop operation, the device will
remain active and continue to charge the battery at a
reduced current level for the given ambient condition.
1.00
1000
0.50
0
25
50
75
100
TA (°C)
Figure 5: Maximum Power Dissipation Before
Entering Thermal Loop.
Next, the power dissipation can be calculated by
the following equation:
ICH(MAX) =
(PD(MAX) - VIN · IOP)
VIN - VBAT
(TJ - TA) - V · I
IN
OP
θJA
ICH(MAX) =
VIN - VBAT
Where:
PD
VIN
VBAT
ICH
IOP
18
= Total Power Dissipation by the Device
= Input Voltage
= Battery Voltage as Seen at the BAT Pin
= Constant Charge Current Programmed for
the Application
= Quiescent Current Consumed by the
Charger IC for Normal Operation [0.5mA]
ICC(MAX) (mA)
800
0.00
TA = 85°C TA = 60°C
TA = 45°C
600
TA = 25°C
400
200
0
4
5
6
7
8
9
10
11
12
13
VIN (V)
Figure 6: Maximum Charging Current Before
the Digital Thermal Loop Becomes Active.
Capacitor Selection
Input Capacitor
In general, it is a good design practice to place a
decoupling capacitor between the IN pin 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. If the AAT3663’s input is to be
used in a system with an external power supply
source, such as a typical AC-to-DC wall adapter,
3663.2007.10.1.0
AAT3663
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
then a CIN capacitor in the range of 10μF should be
used. A larger input capacitor in this application will
minimize switching or power transient effects when
the power supply is "hot plugged" in.
Output Capacitor
The AAT3663 only requires a 1μF ceramic capacitor 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 AAT3663 is to be used in
applications where the battery can be removed
from the charger, such as desktop charging cradles, an output capacitor 10μF or greater is recommended to reduce the effect of the charger cycling
on and off when no battery is present.
Figure 7: AAT3663 Evaluation Board
Top (Component) Side Layout.
3663.2007.10.1.0
Printed Circuit Board Layout
Considerations
For the best results, it is recommended to physically
place the battery pack as close as possible to the
AAT3663 BAT pin. To minimize voltage drops on the
PCB, keep the high current carrying traces adequately wide. For maximum power dissipation of the
AAT3663 3x3mm 14-pin TDFN package, the metal
substrate should be solder bonded to the board. It is
also recommended to maximize the substrate contact to the PCB ground plane layer to further
increase local heat dissipation. Refer to the AAT3663
evaluation board for a good layout example.
Figure 8: AAT3663 Evaluation Board
Bottom Side Layout.
19
AAT3663
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
JP1
ENABLE
JP4
VIN
Green
Red
Red
LED D3 LED D2 LED D1
1
R4 2k
R5 2k
VIN
R6 2k
ADPP#
11
STAT1
8
9
4
C1
10μF
GND
TS
EN
12
10
4V - 13.2V
R7
(see note)
U1
TDFN33-14 AAT3663
5
TS
JP2
STAT2
IN
IN
GND
JP3
EP
TERM
13
BATS
6
BAT
ISET
7
CT
2
BAT
3
C3
0.1μF
R2
R1
10k
1.74k
R3
10k
C2
10μF
GND
C1 1206 X7R 10μF 16V GRM31CR71C106KAC7L
C2 0805 X7R 10μF 10V GRM21BR71A106KE51L
Note: R2 = 10k is set the termination current, 7.5% from the constant charging current
R7 = 10k (for -1 option) R7 = open (for -2 option)
Figure 9: AAT3663 Evaluation Board Schematic Diagram.
20
3663.2007.10.1.0
AAT3663
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
Ordering Information
Battery Cell
Voltage Option
Battery Temperature Sense
Package
Single Cell (4.2V)
Single Cell (4.2V)
Dual Cell (8.4V)
Dual Cell (8.4V)
For Use With Any NTC Thermistor
For Use With 10kΩ NTC Thermistor
For Use With Any NTC Thermistor
For Use With 10kΩ NTC Thermistor
TDFN33-14
TDFN33-14
TDFN33-14
TDFN33-14
Marking1
ZZXYY
Part Number
(Tape and Reel)2
AAT3663IWO-4.2-1-T1
AAT3663IWO-4.2-2-T1
AAT3663IWO-8.4-1-T1
AAT3663IWO-8.4-2-T1
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.
1. XYY = assembly and date code.
2. Sample stock is generally held on part numbers listed in BOLD.
3663.2007.10.1.0
21
AAT3663
1A Linear Li-Ion Battery Charger
for Single and Dual Cell Applications
Package Information
TDFN33-14
Detail "A"
3.000 ± 0.050
2.500 ± 0.050
Index Area
3.000 ± 0.050
1.650 ± 0.050
Top View
Bottom View
+ 0.100
- 0.000
Pin 1 Indicator
(Optional)
0.180 ± 0.050
Side View
0.400 BSC
0.000
0.203 REF
0.750 ± 0.050
0.425 ± 0.050
Detail "A"
All dimensions in millimeters.
1. 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.
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22
3663.2007.10.1.0