LM3622M-4.2 [NSC]
Lithium-Ion Battery Charger Controller; 锂离子电池充电器控制器型号: | LM3622M-4.2 |
厂家: | National Semiconductor |
描述: | Lithium-Ion Battery Charger Controller |
文件: | 总9页 (文件大小:174K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
February 2000
LM3622
Lithium-Ion Battery Charger Controller
low-voltage battery threshold circuitry that removes this drive
when the cell voltage drops below a preset limit. The LVSEL
pin programs this threshold voltage to either 2.7V/cell or
2.15V/cell. The low-voltage detection, which is a user en-
abled feature, provides an output signal that can be used to
enable a ″wake up charge″ source automatically to precon-
dition a deeply discharged pack.
General Description
The LM3622 is a charge controller for Lithium-Ion batteries.
This monolithic integrated circuit accurately controls an ex-
ternal pass transistor for precision Lithium-Ion battery charg-
ing. 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 is available in a standard 8-lead SOIC surface
mount package.
Features
n Versions for charging of 1 cell (4.1V or 4.2V) or 2 cells
(8.2V or 8.4V)
The LM3622 accepts input voltages from 4.5V to 24V. Con-
troller accuracy over temperature is 30mV/cell for A grade
±
±
and 50mV/cell for the standard grade. No precision exter-
n Versions for coke or graphite anode
nal resistors are required. Furthermore, the LM3622’s propri-
etary output voltage sensing circuit drains less than 200nA
from the battery when the input source is disconnected.
±
n Precision ( 30mV/cell) end-of-charge control
n Wide input range: 4.5V-24V
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 sup-
ply range.
n Low battery drain leakage: 200nA
n 15 mA available to drive low cost PNP
Applications
n Cellular phone cradle charger
n PDA/Notebook cradle charger
n Camcorder cradle charger
The LM3622 can sink 15mA minimum at the EXT pin to drive
the base of an external PNP pass transistor. It also has
Typical Application
DS100974-1
© 2000 National Semiconductor Corporation
DS100974
www.national.com
Connection Diagram
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
1
LVSEL
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 VCC. The battery voltage is
sensed between CEL and CS pins.
2
3
LVENB
LV
Input
Low-voltage detection Enable. The low-voltage detection is enabled when this pin is
pulled Low to GND. Pulling this pin HIGH to VCC disables the low-voltage detection.
Output
Output of the low-voltage detection. This pin is a NPN open-collector output that
goes to low impedance state when LVENB is pulled LOW and the battery voltage is
below the threshold set by LVSEL. LV stays in HIGH impedance state at any battery
voltage when LVENB is pulled HIGH to VCC. LV can be used for turning on a low
current source to recondition a deeply depleted battery.
4
5
GND
CS
Ground
Input
IC common.
Input for battery charge current and battery negative-terminal voltage sensing.
Battery charging current is sensed through an external resistor, RCS, connected
between the battery’s negative terminal and GND. The maximum charge current is
regulated to a value of 100mV/RCS
.
6
7
CEL
EXT
Input
Battery positive-terminal voltage sensing.
Output
Output of the controller for driving a PNP transistor or P-MOSFET. The controller
modulates the current sinking into this pin to control the regulation of either the
charge current or the battery voltage.
8
VCC
Power Supply
IC power supply
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2
Ordering Information
Voltage
4.1V
4.1V
4.1V
4.1V
4.2V
4.2V
4.2V
4.2V
8.2V
8.2V
8.2V
8.2V
8.4V
8.4V
8.4V
8.4V
Grade
Accuracy
Order Information
LM3622AM-4.1
LM3622AMX-4.1
LM3622M-4.1
Supplied As
±
±
±
±
±
±
±
±
±
±
A
30mV
30mV
50mV
50mV
30mV
30mV
50mV
50mV
60mV
60mV
95 unit increments in rail
A
Standard
Standard
A
2500 unit increments in tape and reel
95 unit increments in rail
LM3622MX-4.1
LM3622AM-4.2
LM3622AMX-4.2
LM3622M-4.2
2500 unit increments in tape and reel
95 unit increments in rail
A
2500 unit increments in tape and reel
95 unit increments in rail
Standard
Standard
A
LM3622MX-4.2
LM3622AM-8.2
LM3622AMX-8.2
LM3622M-8.2
2500 unit increments in tape and reel
95 unit increments in rail
A
2500 unit increments in tape and reel
95 unit increments in rail
±
±
Standard
Standard
A
100mV
100mV
LM3622MX-8.2
LM3622AM-8.4
LM3622AMX-8.4
LM3622M-8.4
2500 unit increments in tape and reel
95 unit increments in rail
±
60mV
60mV
±
A
2500 unit increments in tape and reel
95 unit increments in rail
±
±
Standard
Standard
100mV
100mV
LM3622MX-8.4
2500 unit increments in tape and reel
3
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=
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Power Dissipation (TA 25˚C)
(Note 4)
Max. Package Dissipation
350mW
Operating Ratings (Note 1)
Supply Voltage (VCC
)
-0.3 to 24V
-0.3 to 24V
-0.3 to 24V
-0.3 to 24V
-0.3 to 24V
2500V
LV
Supply Voltage (VCC
)
4.5V to 24V
−20˚C to 70˚C
−20˚C to 85˚C
EXT (Note 2)
LVSEL
Ambient Temperature Range
Junction Temperature Range
Thermal Resistance, θJA
SOIC-8
LVENB
ESD Susceptibility (Note 3)
Storage Temperature
170˚C/W
−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 VCC 5V/Cell TA TJ 25˚C. Limits with standard typeface apply for TJ 25˚C, and limits in bold-
face type apply over the indicated temperature range.
Symbol
VCC
Parameter
Operating power supply range
Quiescent Current
Conditions
Min
Typ
Max
Units
V
4.5
24.0
ICC
210
µA
=
TJ 0˚C to +70˚C
Regulation Voltage
LM3622A-4.1
LM3622A-8.2
LM3622A-4.2
LM3622A-8.4
LM3622-4.1
=
VCC 4.5V/cell (Note 5)
4.070
8.140
4.170
8.340
4.050
8.100
4.150
8.300
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
V
V
V
V
V
V
V
VCEL
LM3622-8.2
LM3622-4.2
LM3622-8.4
%
Long Term Stability
(Note 6)
0.02
100
=
VCS
ICEL
Current limit threshold at CS pin
VCEL 4V for LM3622-4.X
90
110
mV
=
VCEL 8V for LM3622-8.X
Current in CEL pin
VCC Supply connected
VCC Supply Open
25
200
2.15
2.70
25
µA
nA
=
=
LVth
Low voltage detect threshold
(between pins CS and GND)
LVENB 0V and LVSEL 0V
2.00
2.55
15
2.30
2.85
V/Cell
V/Cell
mA
=
=
LVENB 0V and LVSEL VCC
=
VEXT 4V for LM3622-4.X
IEXT
IIN1
IIN2
EXT pin output sink current
=
VEXT 8V for LM3622-8.X
=
LVSEL input current
LVSEL 5V, LM3622-4.X
20
50
µA
µA
=
LVSEL 10V, LM3622-8.X
=
=
LVENB input current
LVENB 5V, LM3622-4.X
LVENB 10V, LM3622-8.X
20
50
=
ILV
LV pin leakage current
LV pin saturation voltage
LV 5V/Cell
250
nA
V
=
VLV
ISINK 1mA
0.25
0.40
=
TJ −20˚C to 85˚C
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is in-
tended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics.
Note 2: V
is not allowed to exceed (V + 0.3V) or damage to the device may occur.
CC
EXT
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
(maximum junction temperature), θ
JA
JMAX
=
(junction-to-ambient thermal resistance) and T (ambient temperature). The maximum power dissipation at any temperature is: PDiss
A
(T
− T ) / θ up
MAX
JMAX A JA
to the value listed in the Absolute Maximum Ratings.
Note 5: Limits reflect initial accuracy.
=
Note 6: T
85˚C, 1000 hours. Activation energy of 0.78eV used.
J
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4
=
Typical Performance Characteristics Unless otherwise specified, TA 25˚C.
Output Voltage Regulation
Vs VCC
Current Sense Voltage Regulation
Vs VCC
Current Sense Voltage Regulation
Vs Temperature
DS100974-5
DS100974-8
DS100974-4
Output Drive Current Vs VCC
Output Drive Current Vs VCC
Quiescent Current Vs VCC
DS100974-6
DS100974-7
DS100974-3
5
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Functional Description
DS100974-11
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 con-
trol a linear, lithium-ion battery charger in constant voltage
and constant current (CVCC) charge operation. The regu-
lated output voltage is sensed between CEL and CS, and the
battery charge current is sensed across a current-sense re-
sistor 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.
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 VCC via a 20µA current
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
(VCC + 0.3V), otherwise the reverse current from EXT pin to
VCC pin may cause damage to the device.
Tying the LVENB pin to ground enables the controller’s
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
LVSEL pin to GND or VCC respectively. The LV pin is a NPN
open collector output that can be used to turn on a low cur-
rent source to wake up charge a deeply depleted battery.
When the low-voltage detection is disabled (LVENB pulled up
to VCC), the LM3622 always starts the charge cycle in con-
stant current mode at any battery voltage below the control-
LV Pin Current Rating
The LV pin is a low power, NPN open collector output that is
rated to sink 10mA maximum. 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.
ler’s regulation level, and maintains the LV pin at
high-impedance state.
a
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 VCC supply is removed,
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Typical Application
DS100974-13
FIGURE 2. Low Dropout, Constant Current/Constant Voltage Li-ion Battery Charger
The low dropout linear charger shown in Figure 2 provides
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 ini-
tializes the charge cycle based on the battery voltage and
the enable status of the low-voltage detection.
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 bat-
tery is fully charged. Figure 3 shows the timing diagram of
the charge cycle with the low-voltage detection enabled.
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 LM3622 modulates the base drive of Q2 to
regulate a constant 100mV across the current sense resistor
R1, thus generating charge current of
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.
=
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 detection is enabled and the initial bat-
tery 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) (VIN – VCE1 – VD1 – LVth)/R2
where VIN is the input supply voltage, VCE is the
1
collector-emitter on state voltage of Q1, VD1 is the diode for-
ward voltage of D1, and LVth is the low-voltage threshold
level set by switch J2.
7
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Timing Diagram
DS100974-12
FIGURE 3. Typical Charge Cycle with Low-Voltage Detection Enabled.
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8
Physical Dimensions inches (millimeters) unless otherwise noted
SOIC-8 Package
8-Lead Small-Outline Package (M8)
For Ordering, Refer to Ordering Information Table
NS Package Number M08A
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