LM3647
LM3647 Universal Battery Charger for Li-Ion, Ni-MH and Ni-Cd Batteries
Literature Number: SNOS517G
LM3647
OBSOLETE
September 22, 2011
Universal Battery Charger for Li-Ion, Ni-MH and Ni-Cd
Batteries
General Description
The LM3647 is a charge controller for Lithium-Ion (Li-Ion),
Nickel-Metal Hydride (Ni-MH) and Nickel-Cadmium (Ni-Cd)
batteries. The device can use either a pulsed-current charg-
ing or a constant-current charging technique. The device can
also be configured to discharge before charging. Throughout
the charging sequence the LM3647 monitors voltage and/or
temperature and time in order to terminate charging.
Charge termination methods are:
•Negative delta voltage (−ΔV)
•Optional: Delta temperature/delta time (ΔT/Δt)
•Backup: Maximum temperature
•Backup: Maximum time
•Backup: Maximum voltage
If both voltage and temperature fail to trigger the termination
requirements, then the maximum time (configured by external
hardware) steps in which terminates the charging.
In Ni-Cd/Ni-MH mode, four different charging stages are
used:
•Soft-start charge
•Fast charge
•Topping charge
•Maintenance charge
In Li-Ion mode, four different charging stages are used:
•Qualification
•Fast Charge Phase 1, Constant Current
•Fast Charge Phase 2, Constant Voltage
•Maintenance charge
The charge current of the LM3647 is configured via external
resistors, which in turn controls the duty cycle of the PWM
switching control output. For cost-sensitive applications, the
LM3647 charge controller cab be configured to use an exter-
nal current source and no temperature sensor.
When using an external current source, the current is con-
trolled by the LM3647 which turns the current source on and
off. The LM3647 automatically detects the presence of a bat-
tery and starts the charging procedure when the battery is
installed. Whenever an error occurs (e.g., short circuit, tem-
perature too high, temperature too low, bad battery, charge
time over, etc.) the LM3647 will stay in error mode until the
battery is removed or it gets within the allowed charging tem-
perature range. The LM3647 is available in a standard 20-
lead SOIC surface mount package.
Features
■Auto-adaptive fast charge
■High-resolution, accurate voltage monitoring prevents Li-
Ion undercharge or overcharge
■Fast charge, pre-charge and maintenance currents are
provided. Different currents are selectable via external
resistors.
■Fast-charge termination by Δ temperature/Δ time,
maximum voltage, maximum temperature, negative Δ
voltage and maximum time
■Dynamically detects battery insertion, removal, short
circuit and bad battery without additional hardware
■Supports charging of battery packs with 2–8 cells of Ni-Cd/
Ni-MH or 1–4 cells of Li-Ion (1 cell of NiCd/NiMH can be
supported by added external 2x voltage amplifier)
■Three optional LED indicators and Buzzer output indicate
operational modes
■Ni-MH/Ni-Cd charge mode, Li-Ion charge mode or
discharge mode can be selected manually
■Supports control of current feedback power supply and
constant current power supply
Applications
■Battery charging systems for:
—Portable consumer electronics
—Audio/video equipment
—Communications equipment
—Point of sale devices
—Power tools
—Personal convenience products
© 2011 National Semiconductor Corporation 101318 www.national.com
101318 Version 9 Revision 4 Print Date/Time: 2011/09/22 15:21:41
LM3647 Universal Battery Charger for Li-Ion, Ni-MH and Ni-Cd Batteries
2.0 Connection Diagram
10131802
Top View
Order Number LM3647IM
See NS Package Number M20B
2.1 PIN DESCRIPTIONS
Pin No. Name I/O Description
1 SEL3 I Input to Select Power Source or Li-Ion Cell Voltage
2 SEL4 I Input to Select Maintenance Charge Time Out, Connected to an RC-Network
3 RCIN RC-Timing Pin
4 GND Ground
5 VCC 5V, Power Supply
6 RESET I Reset Pin, Active Low
7 LED1 O LED Output
8 LED2 O LED Output
9 LED3 O LED Output
10 VREF I Voltage Reference Analog Input
11 CEXT External Capacitor
12 CEL I Battery Voltage Input (through resistor divider)
13 CS I Current Sense Input
14 TEMP I NTC-Temperature Sensor Input
15 DISCHG O High when Discharging, Else Low
16 SYSOK O System Monitor Output
17 BUZZER O Buzzer Output
18 PWM O Charge Control Output
19 SEL1 I Tri-Level Input, Discharge/Maintenance Charge Select
20 SEL2 I Tri-Level Input, Battery Type Select (NiCd, NiMH, Li-Ion)
2.2 ORDERING INFORMATION
Device Package Temperature
LM3647 20 SOIC −40°C to +85°C
www.national.com 2
101318 Version 9 Revision 4 Print Date/Time: 2011/09/22 15:21:41
LM3647
Typical Application
10131801
3 www.national.com
101318 Version 9 Revision 4 Print Date/Time: 2011/09/22 15:21:41
LM3647
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage
(VCC)7V
Voltage at Any Pin −0.3V to VCC +0.3V
Total Current into
VCC Pin (Source) 100 mA
Total Current out of
GND Pin (Sink) 110 mA
Storage
Temperature Range -65°C to +140°C
Note 1: Note: Absolute Maximum Ratings indicate limits beyond which
damage to the device may occur. DC and AC Electrical Specifications are
not ensured when operating the device at absolute maximum ratings.
DC Electrical Characteristics
−40°C ≤ TA ≤ +85°C unless otherwise specified.
Parameter Conditions Min Typ Max Units
Operating Voltage 4.5 5.5 V
Supply Current 2.5 mA
LED-pin Sink Current 7.5 15 mA
Temperature Input Levels
Ni-Cd/Ni-MH Upper Limit (Voltage at TEMP-pin) 3.15 V
Li-Ion Upper Limit (Voltage at TEMP-pin) 3.0 V
Lower Limit (Voltage at TEMP-pin) 0.5 V
Start Limit (Voltage at TEMP-pin) 2.2 V
L-Ion (for both 4.1 and 4.2V Cells)
Maintenance Charge Minimum Voltage (CEL pin) 2.6 V
Maintenance Charge Restart Voltage (CEL pin) 2.153 V
Good Battery Threshold (CEL pin) 1.2 V
Maintenance Current (Voltage at CS-pin) 2.3 V
Maintenance Current Lower Threshold (Voltage at CS-pin) 2.42 V
Minimum Current Fast Charge Termination (Voltage at CS-pin) 2.3 V
Qualification Current (Voltage at CS-pin) 2.3 V
Maximum Charging Current (Voltage at CS-pin) 1.5 V
Ni-Cd/Ni-MH
Maximum Battery Voltage (CEL pin) 3.017 V
Maximum Battery Current (Voltage at CS-pin) 1.5 V
Battery Presence Limit (CEL pin) 1.0 V
Discharged Battery Limit (CEL pin) 1.7 V
Good Battery Threshold (CEL pin) 1.2 V
Soft Start Current (Voltage at CS-pin) 2.3 V
Topping Charge Current (Voltage at CS-pin) 2.3 V
Maintenance Charge Current (Voltage at CS-pin) 2.425 2.45 V
VREF 2.5 V
AC Electrical Characteristics
Parameter Conditions Min Typ Max Units
RCIN Frequency R = 3.3 kΩ, C = 68 pF 2.5 MHz
Fast-PWM Frequency 250 Hz
Slow-PWM Frequency 0.1 Hz
www.national.com 4
101318 Version 9 Revision 4 Print Date/Time: 2011/09/22 15:21:41
LM3647
3.0 Functional Description
3.1 GENERAL
The LM3647 can be configured to charge three different types
of batteries: Ni-Cd, Ni-MH and Li-Ion. The charger behavior
for Ni-Cd and Ni-MH is similar but the charge curves will ap-
pear slightly different due to the differences in chemistry. The
Ni-Cd/Ni-MH charging algorithm is divided into four phases:
Soft Start: The LM3647 detects that a battery is
connected and optionally verifies that
the temperature is within safe oper-
ating limits (approx. −5°C to +50°C).
Charging starts with a current of 0.2C
and switches into the next phase af-
ter approx. 5 minutes. Error termina-
tion will be triggered by Maximum
Battery Voltage (CEL-pin > 3.017V)
or if the battery voltage does not
reach the defective battery level
(CEL-pin < 1.2V).
Fast Charge: Constant current is applied to the bat-
tery and the LM3647 monitors volt-
age and temperature (optional).
Switching into the next phase will ap-
pear after a voltage drop in the charg-
ing curve: Ni-Cd ∼ 50 mV/cell and Ni-
MH ∼ 17 mV/cell. Error termination
will be triggered by over-tempera-
ture.
ToppingCharge: A current of 0.2C is applied to the
battery for a user defined time (RC
network at SEL4).
MaintenanceCharge: Is user selectable and is a fixed per-
centage of the Fast Charge rate. Dis-
charge before charge is user se-
lectable.
Ni-Cd Charging Curve:
10131803
Ni-MH Charging Curve:
10131804
The Li-Ion charging algorithm is also divided into four phases:
•Qualification: The LM3647 detects that a battery is
connected and verifies that the temperature (optional but
highly recommended for safety reasons) is within limit.
Charging starts with a current of 0.2C and switches into
next phase after approx. 1 minute. Error termination will
be triggered if the battery voltage does not reach the Li-
Ion battery qualification level (CEL-pin < 1.2V) within one
minute.
•Fast Charge Constant Current: Battery voltage will rise
until Maximum Battery Voltage (CEL-pin = 2.675V or
2.74V depending on SEL3) is reached.
•Fast Charge Constant Voltage: Keeps the voltage
constant until the current has decreased below the
threshold (CS at 2.3V).
•Maintenance Charge: Is user selectable and is a fixed
percentage of the Fast Charge rate.
10131805
3.2 ADVANCED PIN DESCRIPTIONS
SEL1 is a selection pin to control the LM3647 discharge and
maintenance charge modes. The pin has three states: tied to
VCC, GND, or unconnected (Hi-Z). When the charger is con-
figured to charge Ni-Cd or Ni-MH batteries, this pin deter-
mines if the charger discharges the battery before charging
or if the charger shall only maintenance charge the battery.
When the charger is configured for Li-Ion batteries, this pin
determines how the charger behaves during maintenance
charge.
SEL1 Charge mode
condition SEL2 = GND (NiCd) or VCC (NiMH)
VCC No discharge before charge
GND Maintenance charge only (no fast charge)
Open Discharge before charge
SEL1 Charge mode
condition SEL2 = Open (Li-Ion)
VCC Maintenance charge indefinite
GND
Maintenance charge indefinite, restart fast-
charge if battery gets discharged (load
connected)
Open No maintenance charge, restart fast charge if
battery becomes discharged
SEL2 is a selection pin to determine the battery type to be
charged. The pin has three states: tied to VCC (Ni-MH), GND
(Ni-Cd), or unconnected (Li-Ion).
SEL2 Battery Type Select
VCC Ni-MH
GND NiCd
Open Li-Ion
SEL3 is a selection pin used to set charger hardware modes.
The pin has two states: tied to VCC or GND. When the LM3647
is configured for Ni-Cd/Ni-MH batteries, this pin selects be-
5 www.national.com
101318 Version 9 Revision 4 Print Date/Time: 2011/09/22 15:21:41
LM3647
tween a power supply with current feedback when tied to
VCC (PWM “fast” frequency) or a constant current source
when tied to GND (PWM “slow” frequency). When configured
for Li-Ion batteries, SEL3 switches between 4.1V cells or 4.2V
cells.
Note: SEL3 must be hard wired to VCC if a charger that supports both Li-Ion
and Ni-Cd/Ni-MH is implemented.
SEL3 PWM Output Frequency Select
output SEL2 = VCC (NiMH) or GND (NiCd)
VCC Current feedback (“fast” PWM frequency)
GND No current feedback (external constant current
source) (“slow” PWM frequency)
SEL3 Li-Ion Cell Voltage Select
output SEL2 = Open (Li-Ion)
VCC 4.2V/cell
GND 4.1V/cell
Note: Current feedback is automatically selected, if LM3647 is configured
for Li-Ion charging (pin SEL2 open).
SEL4 is connected to a RC-network that determines the
charge time-outs. This RC-network is also connected to the
output LED1. (See Section 3.3.2 for details).
RCIN is a high-speed timing pin connected to a RC-network,
used to drive the charger at the right operating frequency.
GND is the ground pin.
VCC is the power-supply pin. This pin should have a 100 nF
decoupling capacitor tied to GND.
RESET is a reset pin.
LED1 is an active-low output used to indicate charge phase.
It is also used when measuring the charge timeout value.
LED2 is an active-low output used to indicate charge or dis-
charge. It also sends out digitally what the LM3647 has read
at the mode selection pins and charge timeout.
LED3 is an active-low output used to indicate charge start/
stop and error.
VREF is the voltage reference analog input. The LM3647 uses
this pin as a reference when measuring the other analog in-
puts. VREF has to be connected to a 2.5V voltage reference
(e.g., LM4040A - 2.5).
CEXT is a timing pin used by the LM3647, it must be con-
nected to a low loss capacitor (polyester).
CEL is an analog input that measures the battery voltage via
a resistor divider network.
CS is an analog input that is connected to a differential am-
plifier that measures the voltage over a small current sensing
resistor, when used in conjunction with current feedback pow-
er supply. When the LM3647 is used with a constant current
power supply, CS should be connected to the 2.5V voltage
reference (pin VREF).
TEMP is an analog input that is connected to the temperature
sensing NTC-resistor (is used). If no temperature sensor is
used, the input must be connected to a voltage between 0.5V
to 2.2V.
DISCHG is a digital output that controls a power-FET that
discharges the batteries before charging them. If the dis-
charge function is not used, leave this pin unconnected.
SYSOK is an open drain output that resets the LM3647 in the
rare case of an internal illegal operating condition. This pin is
connected to the RESET pin to increase reliable operation of
the device in hostile operating environments (e.g., noisy en-
vironments).
BUZZER is a digital output that controls a small FET and turns
an optional buzzer on and off. The buzzer must have it's own
oscillator drive circuitry.
PWM is a digital output that controls the charge voltage or
turns the external current source on and off (depending on
mode-selection).
3.3 CONFIGURATIONS
3.3.1 Maximum Battery Voltage
The maximum battery voltage corresponds to the number of
battery cells. The resistor network in the figure below scales
the battery voltage to a level suitable for the LM3647. For Ni-
Cd/Ni-MH batteries the tolerance of the network is not critical,
and only defines the maximum battery voltage (which is used
as a backup termination method). For Li-Ion batteries the net-
work must be more accurate, and resistors with low toler-
ances must be used (1% or better).
Ni-Cd/Ni-MH
Each battery cell is at nominal voltage 1.2V, but the critical
voltage is rather the maximum voltage per cell specified at
1.85V. The maximum cell voltage is used for maximum volt-
age error termination. If a Ni-Cd/Ni-MH cell fails, it either
becomes shorted or goes high impedance. In the case of high
impedance the cell voltage will reach 1.85V. By multiplying
the number of cells with the maximum cell voltage, the Max-
imum Battery Voltage (VBatm) is achieved.
When the maximum battery voltage has been determined, the
voltage divider network can be dimensioned using the follow-
ing formula (SEL2 connected to VCC or GND):
10131807
Resistor network selection Quick Guide:
No. of
Cells
Ni-Cd/Ni-MH
Nominal Max R6 R7
2 2.4V 3.7V 10k 43k
3 3.6V 5.55V 47k 56k
4 4.8V 7.4V 16k 11k
5 6V 9.25V 62k 30k
6 7.2V 11.1V 15k 5.6k
7 8.4V 12.95V 27k 8.2k
8 9.6V 14.8V 39k 10k
9 10.8V 16.65V 68k 15k
10 12V 18.5V 22k 3.9k
www.national.com 6
101318 Version 9 Revision 4 Print Date/Time: 2011/09/22 15:21:41
LM3647
Example: A standard 9V Ni-Cd block battery is composed of
6 small Ni-Cd cells and therefore has a nominal voltage of
7.2V. See table above for resistor values.
Li-Ion
The voltage divider network for Li-Ion must be selected with
great care for maximum utilization of the batteries. Li-Ion bat-
tery cells have a nominal voltage of 3.6V or 3.7V and the
maximum voltage per cell is specified at 4.1V or 4.2V respec-
tively. By multiplying the number of battery cells with the
maximum cell voltage, it is possible to determine the Maxi-
mum Voltage of the Battery Pack. When the maximum battery
voltage (VBatm) has been determined, the voltage divider net-
work has to be dimensioned using the following formula
(SEL2 open):
Pin SEL3
GND
VCC
The LM3647 supports two different user selectable battery
input voltages on the CEL pin. These are 2.675V (SEL3 tied
to GND) and 2.740V (SEL3 tied to VCC). This selection pin
can be used to configure the charger to handle both 3.6V and
3.7V Li-Ion-cells, without changing the resistor values in the
CEL pin voltage divider network. SEL3 can also be used to
obtain a better match when choosing standard series resistor
values for certain cell combinations.
10131810
Resistor network selection Quick Guide:
No. of
Cells
Li-Ion (3.6V cell)
Nominal Max R6 R7
1 3.6V 4.1V 16k 30k
2 7.2V 8.2V 62k 30k
3 10.8V 12.3V 27k 7.5k
4 14.4V 16.4V 22k 3.9k
No. of
Cells
Li-Ion (3.7V cell)
Nominal Max R6 R7
1 3.7V 4.2V 16k 30k
2 7.4V 8.4V 62k 30k
3 11.1V 12.6V 27k 7.5k
4 14.8V 16.8V 22k 3.9k
3.3.2 Charge Timeout
The LM3647 uses the charge timeout value as a backup ter-
mination method if the normal termination methods fail. The
charge timeout also controls the length of some of the phases,
(e.g., the Topping Charge phase). The timeout is selectable
by choosing different R-C values as shown in the table below:
R Value C Value Ni-Cd/Ni-MH Fast
Charge (minutes)
Ni-Cd/Ni-MH
Topping (minutes)
Li-Ion CC
(minutes)
Li-Ion CV
(minutes)
100 kΩ0 nF 75 20 50 75
100 kΩ10 nF 100 25 70 100
100 kΩ15 nF 160 40 110 160
100 kΩ22 nF 190 50 130 190
100 kΩ33 nF 260 65 170 260
100 kΩ47 nF 330 80 220 330
100 kΩ68 nF 450 115 300 450
100 kΩ100 nF 540 135 360 540
3.3.3 Charge Current
Charge current selection depends on the type of power supply
used. The LM3647 supports two types: current feedback and
constant current. The PWM pin is used to control the power
supply and depending on the supply type, it either produces
a simple on/off signal (PWM slow, constant current supply) or
a PWM signal that is filtered externally to a DC voltage to
regulate the charge voltage in a current feedback power sup-
ply (PWM fast). (SEL3 = VCC, if SEL2 = GND or VCC; auto-
matic if SEL2 = open.)
3.3.3.1 Current Feedback Power Supply
A current feedback type power supply must be used if charg-
ing Li-Ion batteries. When a current feedback power supply is
used, the charge-current is selected by setting the current
sensing resistor and the gain of the differential amplification
stage. The current sensing resistor (R5) should be dimen-
sioned such that a voltage drop over it is not too small,
because the signal will be more susceptible to noise and off-
sets in the amplification-stage. The resistance should not be
too large either (especially in high-current applications), be-
cause this will only generate more heat from the component.
7 www.national.com
101318 Version 9 Revision 4 Print Date/Time: 2011/09/22 15:21:41
LM3647
A suitable value is one that develops about 50 mV across the
resistor when maximum current flows through it.
10131811
The current-sensing signal is amplified, inverted and centered
on the 2.5V reference by the operational amplifier and fed into
the CS pin on the LM3647. The amplification stage must be
dimensioned by setting the appropriate ratio between R1 (R2)
and R3 (R4). The figure above is dimensioned for a maximum
current of about 1.1A. This was calculated using the following
formula:
Example:
R3 = 5.1 kΩ, R1 = 100 kΩ, R5 = 0.047Ω, VREF = 2.5V
→ MaxCurrent ≈ 1.09 Ampere
With a current feedback power supply the PWM pin must be
configured for “fast” mode (SEL3 = VCC; if SEL2 = GND or
VCC; automatic if SEL2 = open).
The RC-network R6, C9 and R5, C1||C2 lowpass-filters the
PWM-signal from the LM3647 to a DC-level that is fed into the
operational amplifier. The resistor R22 is required to prevent
DC-output before the LM3647 has control of the RC-net-
works.
10131813
3.3.3.2 Constant Current Power Supply
A constant current power supply can only be used with Ni-Cd/
Ni-MH batteries, it can not be used to charge Li-Ion batteries.
With a constant current power supply (NiCd/NiMH batteries
only: SEL2 = GND or VCC) the PWM pin must be configured
for “slow” mode (SEL3 = GND). In that mode the PWM-pin
turns the external current source on and off at a rate of 0.1
Hz. (This example is just one of many possible design solu-
tions.) The PWM-pin (SLOW_PWM) turns the transistor Q1
on and off. When the transistor is off the current source is on,
and when the transistor is on the current source is off (V_OUT
at approximate 0.7V). The value of R1 depends on the size
of the charge current (see formula):
www.national.com 8
101318 Version 9 Revision 4 Print Date/Time: 2011/09/22 15:21:41
LM3647
10131815
The charge current duty cycles for the different phases cycles
are listed below:
Charge Phase Charge Current Duty Cycle
Soft Start 10%
Fast Charge 100%
Topping Charge 10%
Maintenance Charge 5%
3.3.4 Dimensioning the Reset Circuitry
The reset-circuitry is designed to hold the RESET pin low until
the power supply to the LM3647 has stabilized. The RC-net-
work (R21 and C4) should be dimensioned in the following
way:
(R21 × C4) > 5×PowerSupplyRiseTime
The diode D2 discharges the capacitance C4 when power
loss occurs. The resistor R20 is used to protect the SYSOK-
pin, and its value is not critical (typical value is 2 kΩ). R20 can
be eliminated if the SYSOK pin is not connected to RESET or
if the value of C4 is ≤0.1 µF. The connection between RESET
and SYSOK is optional but highly recommended for safe op-
eration of the LM3647.
10131816
3.3.5 Dimensioning the RCIN Circuitry
The RC-circuitry is designed to time the charger so it charges
and regulates at the correct frequency. The values of the R
and C are important, because a change in the RC-value gives
a higher or lower operating frequency which affects charge
quality. The capacitance should be a ceramic type and prefer-
ably an NP0 type, which gives the least frequency deviation
with temperature change.
10131817
3.3.6 Dimensioning the DISCHARGE Circuitry
The discharge-circuitry controls the discharge rate during the
discharge phase (if used). The discharge output turns on the
transistor Q2, and a current flows from the battery through the
discharge resistor R8. The current through R8 depends on
battery voltage and the value of R8. This value depends on
the maximum discharge rate for the battery pack. The ap-
proximate value can be calculated using the formula below:
The resistor R7 keeps the transistor Q2 off until the LM3647
has been powered up and is in control of the circuitry.
10131819
3.3.7 BUZZER Output Circuitry
The buzzer-circuitry turns the transistor Q3 on when the
buzzer should sound. If the current consumption for the
buzzer is lower than 0.3 mA then the buzzer may be directly
connected to the BUZZER-pin. Please note that the BUZZER-
9 www.national.com
101318 Version 9 Revision 4 Print Date/Time: 2011/09/22 15:21:41
LM3647
pin does not generate a PWM-signal, therefore the buzzer
must have its own oscillator circuitry. If an electromagnetic
buzzer is used, then the transistor may need a reverse-biased
diode to protect it from harmful voltage spikes.
10131820
3.3.8 User Interface
The user interface consists of up to three LEDs and one
buzzer. The LEDs have four different states:
On, off, slow flash (∼1 Hz) and fast flash (∼10 Hz). The buzzer
has three different states: off, one short beep (∼100 ms) and
one long beep (∼1s).
The user interface is designed in a flexible way. Use of the
buzzer or the LEDs is optional, depending on design require-
ments. It is possible to use the LM3647 with one, two or all
three LEDs.
A single “end of charge” Status LED can be implemented with
a 2-input NAND gate on pins LED1 and LED3. In this imple-
mentation, note that a pull-up resistor is required on LED1 and
LED3.
Ni-Cd/Ni-MH User Interface Scheme
Charge Phase LED1 Status LED2 Status LED3 Status Buzzer Status
No Battery Off Off Off Off
New Battery/Temp-Test Fast Flash Off Off Short Beep
Softstart Charge Slow Flash Off Off Off
Charging On Slow Flash Off Off
Topping Charge On Fast Flash Off Off
Maintenance On Off On Long Beep
Discharge Off Slow Flash Off Off
Temperature Error 2 Fast Flashes Off On Short Beep
Error Fast Flash Off Fast Flash Short Beep
Li-Ion User Interface Scheme
Charge Phase LED1 Status LED2 Status LED3 Status Buzzer Status
No Battery Off Off Off Off
New Battery/Temp-Test Fast Flash Off Off Short Beep
Qualification Charge Slow Flash Off Off Off
Charging CC On Slow Flash Off Off
Charging CV On Fast Flash Off Off
Maintenance On Off On Long Beep
Temperature Error 2 Fast Flashes Off On Short Beep
Error Fast Flash Off Fast Flash Short Beep
3.3.9 Recommended Dimensioning for the Temperature
Sensor
The LM3647 is designed for use with a NTC resistor as a
temperature sensor. The NTC should have 3 kΩ @ 25°C and
a β = 3988. The voltage at TEMP-input must be between 2.2V
and 0.5V for the charger to start. While charging, the voltage
must stay between 3.0V (maximum temperature) for Li-Ion,
or 3.15V (maximum temperature) for Ni-Cd/Ni-MH, and 0.5V
(minimum temperature) or the charger will register a temper-
ature fault and abort the charge. These voltages correspond
to the upper and lower limits for the battery pack temperature.
When no NTC is used the TEMP-input pin must be connected
to a voltage level between 2.2V and 0.5V.
www.national.com 10
101318 Version 9 Revision 4 Print Date/Time: 2011/09/22 15:21:41
LM3647
Typical Configuration Curve, (NTC Characteristics: 3 kΩ @ 25°C, β=3988)
10131821
3.4 TYPICAL CIRCUIT CONFIGURATIONS
3.4.1 Common Circuitry Used for both Ni-Cd/Ni-MH and Li-Ion
10131822
11 www.national.com
101318 Version 9 Revision 4 Print Date/Time: 2011/09/22 15:21:41
LM3647
3.4.2 Circuitry Used Only for Ni-Cd/Ni-MH
10131823
www.national.com 12
101318 Version 9 Revision 4 Print Date/Time: 2011/09/22 15:21:41
LM3647
3.4.3 Circuitry Used for Li-Ion
(can also be used for Ni-Cd and Ni-MH if those chemestries are to be supported with the same charger)
10131824
Note: D7 is required to protect Q4 from reverse current.
13 www.national.com
101318 Version 9 Revision 4 Print Date/Time: 2011/09/22 15:21:41
LM3647
Physical Dimensions inches (millimeters) unless otherwise noted
Molded SO Wide Body Package (WM)
Order Number LM3647IM
NS Package Number M20B
www.national.com 14
101318 Version 9 Revision 4 Print Date/Time: 2011/09/22 15:21:41
LM3647
Notes
15 www.national.com
101318 Version 9 Revision 4 Print Date/Time: 2011/09/22 15:21:41
LM3647
Notes
LM3647 Universal Battery Charger for Li-Ion, Ni-MH and Ni-Cd Batteries
For more National Semiconductor product information and proven design tools, visit the following Web sites at:
www.national.com
Products Design Support
Amplifiers www.national.com/amplifiers WEBENCH® Tools www.national.com/webench
Audio www.national.com/audio App Notes www.national.com/appnotes
Clock and Timing www.national.com/timing Reference Designs www.national.com/refdesigns
Data Converters www.national.com/adc Samples www.national.com/samples
Interface www.national.com/interface Eval Boards www.national.com/evalboards
LVDS www.national.com/lvds Packaging www.national.com/packaging
Power Management www.national.com/power Green Compliance www.national.com/quality/green
Switching Regulators www.national.com/switchers Distributors www.national.com/contacts
LDOs www.national.com/ldo Quality and Reliability www.national.com/quality
LED Lighting www.national.com/led Feedback/Support www.national.com/feedback
Voltage References www.national.com/vref Design Made Easy www.national.com/easy
PowerWise® Solutions www.national.com/powerwise Applications & Markets www.national.com/solutions
Serial Digital Interface (SDI) www.national.com/sdi Mil/Aero www.national.com/milaero
Temperature Sensors www.national.com/tempsensors SolarMagic™ www.national.com/solarmagic
PLL/VCO www.national.com/wireless PowerWise® Design
University
www.national.com/training
THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION
(“NATIONAL”) PRODUCTS. NATIONAL MAKES NO REPRESENTATIONS OR WARRANTIES WITH RESPECT TO THE ACCURACY
OR COMPLETENESS OF THE CONTENTS OF THIS PUBLICATION AND RESERVES THE RIGHT TO MAKE CHANGES TO
SPECIFICATIONS AND PRODUCT DESCRIPTIONS AT ANY TIME WITHOUT NOTICE. NO LICENSE, WHETHER EXPRESS,
IMPLIED, ARISING BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS IS GRANTED BY THIS
DOCUMENT.
TESTING AND OTHER QUALITY CONTROLS ARE USED TO THE EXTENT NATIONAL DEEMS NECESSARY TO SUPPORT
NATIONAL’S PRODUCT WARRANTY. EXCEPT WHERE MANDATED BY GOVERNMENT REQUIREMENTS, TESTING OF ALL
PARAMETERS OF EACH PRODUCT IS NOT NECESSARILY PERFORMED. NATIONAL ASSUMES NO LIABILITY FOR
APPLICATIONS ASSISTANCE OR BUYER PRODUCT DESIGN. BUYERS ARE RESPONSIBLE FOR THEIR PRODUCTS AND
APPLICATIONS USING NATIONAL COMPONENTS. PRIOR TO USING OR DISTRIBUTING ANY PRODUCTS THAT INCLUDE
NATIONAL COMPONENTS, BUYERS SHOULD PROVIDE ADEQUATE DESIGN, TESTING AND OPERATING SAFEGUARDS.
EXCEPT AS PROVIDED IN NATIONAL’S TERMS AND CONDITIONS OF SALE FOR SUCH PRODUCTS, NATIONAL ASSUMES NO
LIABILITY WHATSOEVER, AND NATIONAL DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY RELATING TO THE SALE
AND/OR USE OF NATIONAL PRODUCTS INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A PARTICULAR
PURPOSE, MERCHANTABILITY, OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY
RIGHT.
LIFE SUPPORT POLICY
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR
SYSTEMS WITHOUT THE EXPRESS PRIOR WRITTEN APPROVAL OF THE CHIEF EXECUTIVE OFFICER AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:
Life support devices or systems are devices which (a) are intended for surgical implant into the body, or (b) support or sustain life and
whose failure to perform when properly used in accordance with instructions for use provided in the labeling can be reasonably expected
to result in a significant injury to the user. A critical component is any component in a life support device or system whose failure to perform
can be reasonably expected to cause the failure of the life support device or system or to affect its safety or effectiveness.
National Semiconductor and the National Semiconductor logo are registered trademarks of National Semiconductor Corporation. All other
brand or product names may be trademarks or registered trademarks of their respective holders.
Copyright© 2011 National Semiconductor Corporation
For the most current product information visit us at www.national.com
National Semiconductor
Americas Technical
Support Center
Email: support@nsc.com
Tel: 1-800-272-9959
National Semiconductor Europe
Technical Support Center
Email: europe.support@nsc.com
National Semiconductor Asia
Pacific Technical Support Center
Email: ap.support@nsc.com
National Semiconductor Japan
Technical Support Center
Email: jpn.feedback@nsc.com
www.national.com
101318 Version 9 Revision 4 Print Date/Time: 2011/09/22 15:21:41
IMPORTANT NOTICE
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements,
and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should
obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are
sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment.
TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI’s standard
warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where
mandated by government requirements, testing of all parameters of each product is not necessarily performed.
TI assumes no liability for applications assistance or customer product design. Customers are responsible for their products and
applications using TI components. To minimize the risks associated with customer products and applications, customers should provide
adequate design and operating safeguards.
TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask work right,
or other TI intellectual property right relating to any combination, machine, or process in which TI products or services are used. Information
published by TI regarding third-party products or services does not constitute a license from TI to use such products or services or a
warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual
property of the third party, or a license from TI under the patents or other intellectual property of TI.
Reproduction of TI information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied
by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive
business practice. TI is not responsible or liable for such altered documentation. Information of third parties may be subject to additional
restrictions.
Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all
express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice. TI is not
responsible or liable for any such statements.
TI products are not authorized for use in safety-critical applications (such as life support) where a failure of the TI product would reasonably
be expected to cause severe personal injury or death, unless officers of the parties have executed an agreement specifically governing
such use. Buyers represent that they have all necessary expertise in the safety and regulatory ramifications of their applications, and
acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products
and any use of TI products in such safety-critical applications, notwithstanding any applications-related information or support that may be
provided by TI. Further, Buyers must fully indemnify TI and its representatives against any damages arising out of the use of TI products in
such safety-critical applications.
TI products are neither designed nor intended for use in military/aerospace applications or environments unless the TI products are
specifically designated by TI as military-grade or "enhanced plastic."Only products designated by TI as military-grade meet military
specifications. Buyers acknowledge and agree that any such use of TI products which TI has not designated as military-grade is solely at
the Buyer's risk, and that they are solely responsible for compliance with all legal and regulatory requirements in connection with such use.
TI products are neither designed nor intended for use in automotive applications or environments unless the specific TI products are
designated by TI as compliant with ISO/TS 16949 requirements. Buyers acknowledge and agree that, if they use any non-designated
products in automotive applications, TI will not be responsible for any failure to meet such requirements.
Following are URLs where you can obtain information on other Texas Instruments products and application solutions:
Products Applications
Audio www.ti.com/audio Communications and Telecom www.ti.com/communications
Amplifiers amplifier.ti.com Computers and Peripherals www.ti.com/computers
Data Converters dataconverter.ti.com Consumer Electronics www.ti.com/consumer-apps
DLP®Products www.dlp.com Energy and Lighting www.ti.com/energy
DSP dsp.ti.com Industrial www.ti.com/industrial
Clocks and Timers www.ti.com/clocks Medical www.ti.com/medical
Interface interface.ti.com Security www.ti.com/security
Logic logic.ti.com Space, Avionics and Defense www.ti.com/space-avionics-defense
Power Mgmt power.ti.com Transportation and Automotive www.ti.com/automotive
Microcontrollers microcontroller.ti.com Video and Imaging www.ti.com/video
RFID www.ti-rfid.com
OMAP Mobile Processors www.ti.com/omap
Wireless Connectivity www.ti.com/wirelessconnectivity
TI E2E Community Home Page e2e.ti.com
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright ©2011, Texas Instruments Incorporated
