Datasheet LM3622MX-8.4, LM3622MX-8.2, LM3622MX-4.2, LM3622MX-4.1, LM3622M-4.1 Datasheet (NSC)

LM3622
Lithium-Ion Battery Charger Controller

LM3622 Lithium-Ion Battery Charger Controller

February 2000

General Description

The LM3622 is a charge controller for Lithium-Ion batteries.
This monolithic integrated circuit accurately controls an ex­ternal passtransistor for precision Lithium-Ion battery charg­ing. The LM3622 provides a constant voltage or constant
current (CVCC) configuration that changes, as necessary,to
optimally charge lithium-ion battery cells. Voltage charging
versions (4.1V, 4.2V,8.2V, and 8.4V) are available for one or
two cell battery packs and for coke or graphite anode battery
chemistry.

The LM3622 accepts input voltages from 4.5V to 24V. Con­troller accuracy over temperature is

±

and

50mV/cell for the standard grade. No precision exter­nal resistors are required. Furthermore, the LM3622’spropri­etary output voltage sensing circuit drains less than 200nA
from the battery when the input source is disconnected.

The LM3622 circuitry includes functions for regulating the
charge voltage with a temperature compensated bandgap
reference and regulating the current with an external sense
resistor. The internal bandgap insures excellent controller
performance over the operating temperature and input sup­ply range.

The LM3622 can sink 15mA minimum at the EXT pin to drive
the base of an external PNP pass transistor. It also has

±

30mV/cell for A grade

Typical Application

low-voltage battery threshold circuitry that removes thisdrive
when the cell voltage drops below a preset limit. The LV
pin programs this threshold voltage to either 2.7V/cell or

2.15V/cell. The low-voltage detection, which is a user en­abled feature, provides an output signal that can be used to
enable a ″wake up charge″ source automatically to precon­dition a deeply discharged pack.

The LM3622 is available in a standard 8-lead SOIC surface
mount package.

SEL

Features

n Versions for charging of 1 cell (4.1V or 4.2V) or 2 cells

(8.2V or 8.4V)

n Versions for coke or graphite anode
n Precision (
n Wide input range: 4.5V-24V
n Low battery drain leakage: 200nA
n 15 mA available to drive low cost PNP

±

30mV/cell) end-of-charge control

Applications

n Cellular phone cradle charger
n PDA/Notebook cradle charger
n Camcorder cradle charger

DS100974-1

© 2000 National Semiconductor Corporation DS100974 www.national.com

Connection Diagram

LM3622

8-Lead Surface Mount Package

DS100974-2

Refer to the Ordering Information Table in this Datasheet for Specific Part Number

See NS Package M08A

Pin Description

Pin No. Name I/O Description

1LV

2LV

SEL

ENB

3LV

4 GND Ground IC common.
5 CS Input Input for battery charge current and battery negative-terminal voltage sensing.

6 CEL Input Battery positive-terminal voltage sensing.
7 EXT Output Output of the controller for driving a PNP transistor or P-MOSFET. The controller

8V

CC

Input Low-voltage detection threshold Select. The threshold is 2.15V/cell when this pin is

pulled low to GND and 2.70V/cell when it is pulled up to V
sensed between CEL and CS pins.

Input Low-voltage detection Enable. The low-voltage detection is enabled when this pin is

pulled Low to GND. Pulling this pin HIGH to V

Output Output of the low-voltage detection. This pin is a NPN open-collector output that

goes to low impedance state when LV
below the threshold set by LV
voltage when LV

is pulled HIGH to VCC. LV can be used for turning on a low

ENB

. LV stays in HIGH impedance state at any battery

SEL

current source to recondition a deeply depleted battery.

Battery charging current is sensed through an external resistor, R
between the battery’s negative terminal and GND. The maximum charge current is
regulated to a value of 100mV/R

.

CS

modulates the current sinking into this pin to control the regulation of either the
charge current or the battery voltage.

Power Supply IC power supply

. The battery voltage is

CC

disables the low-voltage detection.

CC

is pulled LOW and the battery voltage is

ENB

, connected

CS

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Ordering Information

Voltage Grade Accuracy Order Information Supplied As

4.1V A

4.1V A

4.1V Standard

4.1V Standard

4.2V A

4.2V A

4.2V Standard

4.2V Standard

8.2V A

8.2V A

8.2V Standard

8.2V Standard

8.4V A

8.4V A

8.4V Standard

8.4V Standard

±

30mV LM3622AM-4.1 95 unit increments in rail

±

30mV LM3622AMX-4.1 2500 unit increments in tape and reel

±

50mV LM3622M-4.1 95 unit increments in rail

±

50mV LM3622MX-4.1 2500 unit increments in tape and reel

±

30mV LM3622AM-4.2 95 unit increments in rail

±

30mV LM3622AMX-4.2 2500 unit increments in tape and reel

±

50mV LM3622M-4.2 95 unit increments in rail

±

50mV LM3622MX-4.2 2500 unit increments in tape and reel

±

60mV LM3622AM-8.2 95 unit increments in rail

±

60mV LM3622AMX-8.2 2500 unit increments in tape and reel

±

100mV LM3622M-8.2 95 unit increments in rail

±

100mV LM3622MX-8.2 2500 unit increments in tape and reel

±

60mV LM3622AM-8.4 95 unit increments in rail

±

60mV LM3622AMX-8.4 2500 unit increments in tape and reel

±

100mV LM3622M-8.4 95 unit increments in rail

±

100mV LM3622MX-8.4 2500 unit increments in tape and reel

LM3622

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Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,

LM3622

please contact the National Semiconductor Sales Office/

Power Dissipation (T
(Note 4)

Max. Package Dissipation 350mW

=

25˚C)

A

Distributors for availability and specifications.

Supply Voltage (V
LV

) -0.3 to 24V

CC

-0.3 to 24V
EXT (Note 2) -0.3 to 24V
LV
LV

SEL
ENB

-0.3 to 24V

-0.3 to 24V
ESD Susceptibility (Note 3) 2500V

Operating Ratings (Note 1)

Supply Voltage (V
Ambient Temperature Range −20˚C to 70˚C
Junction Temperature Range −20˚C to 85˚C
Thermal Resistance, θ

SOIC-8 170˚C/W

) 4.5V to 24V

CC

JA

Storage Temperature −40˚C to +125˚C
Lead Temp. Soldering

Vapor Phase (60 sec.)
Infrared (15 sec.)

215˚C
220˚C

Electrical Characteristics

LM3622-XX

Unless otherwise specified V
face type apply over the indicated temperature range.

CC

=

5V/Cell T

Symbol Parameter Conditions Min Typ Max Units

V

CC

I

CC

Operating power supply range 4.5 24.0 V
Quiescent Current 210 µA
Regulation Voltage

LM3622A-4.1
LM3622A-8.2
LM3622A-4.2

V

CEL

LM3622A-8.4
LM3622-4.1
LM3622-8.2
LM3622-4.2
LM3622-8.4

Long Term Stability (Note 6) 0.02

V

I

CS

CEL

Current limit threshold at CS pin V

Current in CEL pin VCCSupply connected 25 µA

LVth Low voltage detect threshold

(between pins CS and GND)

I

EXT

I

IN1

I

IN2

I

LV

V

LV

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is in­tended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics.

Note 2: V
Note 3: Rating is for the human body model, a 100 pF capacitor discharged through a 1.5kΩ resistor into each pin.
Note 4: The maximum power dissipation must be de-rated at elevated temperatures and is limited by T

(junction-to-ambient thermal resistance) and TA(ambient temperature). The maximum power dissipation at any temperature is: PDiss
to the value listed in the Absolute Maximum Ratings.

Note 5: Limits reflect initial accuracy.
Note 6: T

EXT pin output sink current V

LV

input current LV

SEL

LV

input current LV

ENB

LV pin leakage current LV=5V/Cell 250 nA
LV pin saturation voltage I

is not allowed to exceed (VCC+ 0.3V) or damage to the device may occur.

EXT

=

85˚C, 1000 hours. Activation energy of 0.78eV used.

J

=

=

T

A

25˚C. Limits with standard typeface apply for T

J

=

0˚C to +70˚C

T

J

=

4.5V/cell (Note 5) 4.070

V

CC

8.140

4.170

8.340

4.050

8.100

4.150

8.300

=

4V for LM3622-4.X

CEL

=

8V for LM3622-8.X

V

CEL

V

Supply Open 200 nA

CC

=

LV

ENB

=

LV

ENB

=

4V for LM3622-4.X

EXT

=

8V for LM3622-8.X

V

EXT

=

SEL

=

LV

SEL

=

ENB

=

LV

ENB

=

1mA

SINK

=

−20˚C to 85˚C

T

J

0V and LV
0V and LV

5V, LM3622-4.X
10V, LM3622-8.X

5V, LM3622-4.X
10V, LM3622-8.X

SEL
SEL

=

0V

=

V

CC

90 100 110 mV

2.00 2.15 2.30 V/Cell

2.55 2.70 2.85 V/Cell
15 25 mA

JMAX

=

25˚C, and limits in bold-

J

4.100

8.200

4.200

8.400

4.100

8.200

4.200

8.400

4.130

8.260

4.230

8.460

4.150

8.300

4.250

8.500

20
50

20
50

0.25 0.40 V

(maximum junction temperature), θ

MAX

=

(T

JMAX−TA

V
V
V
V
V
V
V

%

µA

µA

)/θJAup

JA

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LM3622

Typical Performance Characteristics Unless otherwise specified, T

Output Voltage Regulation
Vs V

CC

Output Drive Current Vs V

DS100974-5

CC

Current Sense Voltage Regulation
Vs V

CC

DS100974-8

Output Drive Current Vs V

CC

Current Sense Voltage Regulation
Vs Temperature

Quiescent Current Vs V

=

25˚C.

A

DS100974-4

CC

DS100974-6

DS100974-7

DS100974-3

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Functional Description

LM3622

FIGURE 1. LM3622 Simplified Block Diagram

The simplified LM3622 block diagram in

Figure 1

gives a
general idea of the circuit operation. The controller integrates
the reference, feedback and drive functions on-chip to con­trol a linear, lithium-ion battery charger in constant voltage
and constant current (CVCC) charge operation. The regu­lated output voltage is sensed between CEL and CS, and the
battery charge current is sensed across a current-sense re­sistor between CS and GND. The EXT pin is designed for
driving a series pass element, which can be a PNP transistor
or a P-MOSFET.

Tying the LV

pin to ground enables the controller’s

ENB

low-voltage detection circuit. When the low-voltage detection
circuit is enabled and a battery voltage below a preset
threshold is detected, the LM3622 will drive the LV pin low
and shut off the current flowing into the EXT pin to suspend
the CVCC charge process. The low-voltage threshold is user
selectable to be either 2.15V/cell or 2.7V/cell by pulling the
LV

pin to GND or VCCrespectively. The LV pin is a NPN

SEL

open collector output that can be used to turn on a low cur­rent source to wake up charge a deeply depleted battery.
When the low-voltage detection is disabled (LV

ENB

pulled up
to VCC), the LM3622 always starts the charge cycle in con­stant current mode at any battery voltage below the control­ler’s regulation level, and maintains the LV pin at a
high-impedance state.

DS100974-11

the power down switch will disconnect the resistor divider
from the CS pin, preventing the battery from discharging
through the CEL pin.

EXT Pin

The EXT pin is internally pulled up to V

via a 20µA current

CC

source making it possible to eliminate the external
base-emitter resistor when driving a PNP transistor, or the
gate-source resistor when driving a P-MOSFET. However,
the voltage applied to EXT is not allowed to be higher than
(V

+ 0.3V), otherwise the reverse current from EXT pin to

CC

V

pin may cause damage to the device.

CC

LV Pin Current Rating

The LV pin is a low power, NPN open collector output that is
rated to sink 10mAmaximum.Therefore,the value of the pull
up resistor should be chosen high enough to limit the current
to be less than 10mA.

CS Pin

In normal operation, the current limit threshold voltage for
the CS pin is 100mV typical. In case of a fault condition, the
voltage to this pin should be limited to below 5V.

Application Information

CEL Pin Current Drain

The LM3622 has an internal power down switch in series
with the on-chip resistor divider that is used for sensing the
battery voltage. In the event that the V

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supply is removed,

CC

Typical Application

FIGURE 2. Low Dropout, Constant Current/Constant Voltage Li-ion Battery Charger

The low dropout linear charger shown in
constant current and constant voltage charging of 1-cell
lithium-ion battery packs. J1 and J2 are used for selecting
the operation of the low-voltage detection. The LM3622 ini­tializes the charge cycle based on the battery voltage and
the enable status of the low-voltage detection.

When the low-voltage detection is disabled, the LM3622
starts the charge cycle constant current mode if the battery
voltage is below the controller’s regulation level. In constant
current mode, the LM3622modulates the base drive of Q2 to
regulate a constant 100mV across the current sense resistor
R1, thus generating charge current of

I-charge=0.1V/R1
which is equal to 0.5A in this case.
Once the battery voltage reaches the target regulation level

set by the LM3622, Q2 is controlled to regulate the voltage
across the battery, and the constant voltage mode of the
charging cycle starts. Once the charger is in the constant
voltage mode, the charger maintains a regulated voltage
across the battery and the charging current is dependent on
the state of the charge of the battery.As the cell approaches
a fully charged condition, the charge current falls to a very
low value.

When the low-voltage detectionis enabled and the initial bat­tery voltage is below the low-voltage threshold, the LM3622
turns Q2 off and forces the LV pin low to drive Q1 on to start
a wake up charge phase. Q1 in conjunction with R2 provides
a low current source to recondition the battery. During the
wake up charge mode, Q1 is driven into saturation and the
wake up charge current is programmed by R2,

I-charge (wake)=(V

where V

is the input supply voltage, VCE1isthe

IN

IN–VCE

collector-emitter on state voltage of Q1, V
ward voltage of D1, and LVth is the low-voltage threshold
level set by switch J2.

Figure 2

provides

1–VD1 – LVth)/R2

1 is the diode for-

D

DS100974-13

Once the battery voltage reaches the low-voltage threshold,
the LV pin transitions to a high-impedance state to end the
wake up charge phase, and the EXT pin resumes the base
drive of Q2 to start the constant current mode. The charging
cycle is completed in constant voltage mode when the bat­tery is fully charged.

Figure 3

shows the timing diagram of

the charge cycle with the low-voltage detection enabled.
D1 is a general-purpose silicon diode used for isolating the

battery from the charger circuitry that could discharge the
battery when the input source is removed. Changing D1 to a
Schottky diode will reduce the overall dropout voltage of the
circuit, but the penalty is higher leakage current associated
with Schottky diodes.

LM3622

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Timing Diagram

LM3622

DS100974-12

FIGURE 3. Typical Charge Cycle with Low-Voltage Detection Enabled.

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Physical Dimensions inches (millimeters) unless otherwise noted

LM3622 Lithium-Ion Battery Charger Controller

SOIC-8 Package

8-Lead Small-Outline Package (M8)

For Ordering, Refer to Ordering Information Table

NS Package Number M08A

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