INTEGRATED CIRCUITS
NE57605
Lithium-ion battery protector
for 3 or 4 cell battery packs
Product data
2001 Oct 03
Philips
Semiconductors
Philips Semiconductors
Product data
Lithium-ion battery protector for
3 or 4 cell battery packs
NE57605
GENERAL DESCRIPTION
The NE57605 is a 3-4-cell Li-ion protection IC. Its over- and
under-voltage accuracy is trimmed to within
±25
mV (5%), and is
available to match the requirements of all lithium-ion cells
manufactured in the market today.
FEATURES
•
Trimmed overvoltage trip point to within
±25
mV
•
Programmable overvoltage trip time delay
•
Trimmed undervoltage trip point to within
±25
mV
•
Very low undervoltage sleep quiescent current 2 mA.
•
Discharge overcurrent cutoff.
•
Low operating current (10 mA).
•
Very small package (TSOP-20A).
SIMPLIFIED SYSTEM DIAGRAM
V
C4
OV REF
APPLICATIONS
•
Laptop Computers
•
Other battery-powered devices
V
CC
V
CC
UV REF
V
C3
OV REF
OV
DEADTIME
CONTROL
V
CC
CF
UV REF
C
DLY(OV)
V
C2
OV REF
SEL
UV REF
V
C1
OV REF
V
CC
SEL
UV REF
GND
CHARGER
DETECTOR
SEL
CS
OC REF
OVERCURRENT
DEADTIME
CONTROL
CON
C
DLY(UV)
C
DLY(OC)
OD
DEADTIME
CONTROL
DF
SL01582
Figure 1. Simplified system diagram.
2001 Oct 03
2
853-2295 27198
Philips Semiconductors
Product data
Lithium-ion battery protector for
3 or 4 cell battery packs
NE57605
ORDERING INFORMATION
PACKAGE
TYPE NUMBER
NE57605CD
NAME
TSOP-20A
DESCRIPTION
plastic thin shrink small outline package; 20 leads; body width 4.4 mm
TEMPERATURE
RANGE
–20 to +70
°C
Part number marking
Each device is marked with a four letter code. The first three letters
in the top line of markings designate the product. The fourth letter,
represented by “x”, is a date code. The remaining markings are
manufacturing codes.
Part Number
NE57605CD
Marking
ALZx
PIN CONFIGURATION
CF
NC
CS
NC
DF
NC
C
DLY(UV)
C
DLY(OC)
C
DLY(OV)
1
2
3
4
5
6
7
8
9
20 V
CC
19 NC
18 V
C4
17 V
C3
16 V
C2
15 V
C1
14 NC
13 CON
12 NC
11 SEL
GND 10
SL01583
Figure 2. Pin configuration.
PIN DESCRIPTION
PIN
1
SYMBOL
CF
I/O
Output
DESCRIPTION
Overcharge detection output pin.
NPNTr open collector output.
Normal: high impedance. Overcharge: LOW.
Not Connected.
Overcurrent detection pin. Monitors load current equivalently by the voltage drop between discharge
control FET source and drain, and makes DF pin HIGH when the voltage goes below overcurrent detection
voltage, turning off discharge control FET. After overcurrent detection, current flows from this pin and when
there is a light load, overcurrent mode is released. This function does not operate in overdischarge mode.
Discharge control FET (P-ch) drive pin. Normal: LOW. Overdischarge: HIGH.
Overdischarge detection dead time setting pin. Dead time can be set by connecting a capacitor between
C
DLY(UV)
pin and ground.
Overcurrent detection dead time setting pin. Dead time can be set by connecting a capacitor between
C
DLY(OC)
pin and ground.
Overcharge detection dead time setting pin. Dead time can be set by connecting a capacitor between
C
DLY(OV)
pin and ground.
Ground pin.
3/4 cell selection pin.
SEL pin = GND: 3 cell (Connect V
C1
to GND).
SEL pin = V
CC
: 4 cell.
Discharge FET ON/OFF pin.
CON pin LOW; DF pin LOW (Normal mode).
CON pin HIGH; DF pin HIGH (Discharging prohibited).
V1 cell high side voltage input pin.
V2 cell high side voltage and V3 cell low side voltage input pin.
V3 cell high side voltage and V4 cell low side voltage input pin.
V4 cell high side voltage input pin.
Power supply input pin.
2, 4, 6,
12, 14, 19
3
NC
CS
–
Input
5
7
8
9
10
11
DF
C
DLY(UV)
C
DLY(OC)
C
DLY(OV)
GND
SEL
Output
Input
Input
Input
–
Input
13
CON
Input
15
16
17
18
20
V
C1
V
C2
V
C3
V
C4
V
CC
Input
Input
Input
Input
–
2001 Oct 03
3
Philips Semiconductors
Product data
Lithium-ion battery protector for
3 or 4 cell battery packs
NE57605
MAXIMUM RATINGS
SYMBOL
V
CC(max)
V
CF(max)
V
SEL(max)
V
CON(max)
T
opr
T
stg
P
D
Power supply voltage
CF pin impressed voltage
SEL pin impressed voltage
CON pin impressed voltage
Operating ambient temperature range
Storage temperature
Power dissipation
PARAMETER
MIN.
–0.3
–0.3
–0.3
–0.3
–20
–40
–
MAX.
+24
+24
+24
+24
+70
+125
300
UNIT
V
V
V
V
°C
°C
mW
ELECTRICAL CHARACTERISTICS
T
amb
= 25
°C;
V
IN
= V
CE
, unless otherwise specified.
SYMBOL
I
CC1
I
CC2
I
CC3
I
CC4
I
CC5
I
1V4
I
2V4
I
3V4
I
V3
I
V2
I
V1
V
CELL
U
∆V
U
t
OV
V
CELL
S
V
CELL
D
∆V
DS
t
CDC
V
OC
∆V
OC
t
COL1
t
COL2
t
COL3
I
SO
D
CH
I
SI
D
CH
V
TH
D
C
H
V
TH
D
C
L
I
SI
OV
I
LK
OV
PARAMETER
Current consumption 1 (V
CC
pin)
Current consumption 2 (V
CC
pin)
Current consumption 3 (V
CC
pin)
Current consumption 4 (V
CC
pin)
Current consumption 5 (V
CC
pin)
Consumption current (V4 pin) 1
Consumption current (V4 pin) 2
Consumption current (V4 pin) 3
V3 pin input current
V2 pin input current
V1 pin input current
Overcharge detection voltage
Overcharge hysteresis voltage
Overcharge sensing dead time
Overdischarge detection voltage
Discharge resume voltage
Overdischarge hysteresis voltage
Overdischarge sensing dead time
Overcurrent detection voltage
Overcurrent hysteresis voltage
Overcurrent sensing dead time 1
Overcurrent sensing dead time 2
Overcurrent sensing dead time 3
DF pin source current
DF pin sink current
DF pin output voltage HIGH
DF pin output voltage LOW
OV pin sink current
OV pin leak current
CON pin LOW voltage
CON pin HIGH voltage
CON pin current
SEL pin LOW voltage
SEL pin HIGH voltage
SEL pin current
C
OL
= 0.001
µF
C
OL
= 0.001
µF;
V
CC
– CS > 1.0 V
C
OL
= 0.001
µF
Load release conditions 500 kΩ
V
CELL
= 1.8 V; SW1: A V
DF
= V
CC
–0.8 V
V
CELL
= 3.5 V; SW1: A V
DF
= 0.8 V
V
CC
–V
DF
; I
SO
= 20
µA;
SW1: B
V
DF
–GND; I
SI
= –20
µA;
SW1: B
V
OV
= 0.4 V; T
amb
= –20
°C
to +70
°C
V
OV
= 24 V
DF = HIGH
DF = LOW
V
CELL
= 3.5 V; CON = 0.4 V
for 3 cell
for 4 cell
V
CELL
= 3.5 V; SEL = 0.4 V
20
20
–
–
100
–
–
V
CC
–0.4
–
–
V
CC
–0.4
–
–
–
–
–
–
–
–
–
1
–
–
1
–
–
0.8
0.8
–
0.1
0.4
–
2
0.4
–
2
µA
µA
V
V
µA
µA
V
V
µA
V
V
µA
CONDITIONS
V
CELL
= 4.4 V; CON = 0 V
V
CELL
= 3.5 V; CON = 0 V
V
CELL
= 1.8 V; CON = 0 V
V
CELL
= 3.5 V; CON = V
CC
V
CELL
= 1.8 V; CON = V
CC
V
CELL
= 4.4 V
V
CELL
= 3.5 V
V
CELL
= 1.8 V
V
CELL
= 3.5 V
V
CELL
= 3.5 V
V
CELL
= 3.5 V
V
CELL
: 4.2 V
→
4.4 V; T
amb
= 0
∼
50
°C
V
CELL
: 4.2 V
→
4.4 V
→
3.9 V
C
OV
= 0.1
µF
V
CELL
: 3.5 V
→
1.8 V
V
CELL
: 1.8 V
→
3.5 V
V
CELL
D – V
CELL
S
C
DC
= 0.1
µF
V
CC
– V
CS
; DF
Min.
–
–
–
–
–
–
–
–
–300
–300
–300
4.10
–
0.5
2.20
2.85
0.45
0.5
135
–
5
–
5
Typ.
55
27
2
12
1
10
8
2.5
0
0
0
4.35
200
1.0
2.30
3.00
0.70
1.0
150
20
10
1.5
10
Max.
110
50
4
20
2
20
15
5.0
+300
+300
+300
4.60
260
1.5
2.40
3.15
0.95
1.5
165
40
15
3.0
15
UNIT
µA
µA
µA
µA
µA
µA
µA
µA
nA
nA
nA
V
mV
s
V
V
V
s
mV
mV
ms
ms
ms
Overcurrent reset conditions
2001 Oct 03
4
Philips Semiconductors
Product data
Lithium-ion battery protector for
3 or 4 cell battery packs
NE57605
TECHNICAL DISCUSSION
Lithium cell safety
Lithium-ion and lithium-polymer cells have a higher energy density
than that of nickel-cadmium or nickel metal hydride cells and have a
much lighter weight. This makes the lithium cells attractive for use in
portable products. However, lithium cells require a protection circuit
within the battery pack because certain operating conditions can be
hazardous to the battery or the operator, if allowed to continue.
Lithium cells have a porous carbon or graphite anode where lithium
ions can lodge themselves in the pores. The lithium ions are
separated, which avoids the hazards of metallic lithium.
If the lithium cell is allowed to become overcharged, metallic lithium
plates out onto the surface of the anode and volatile gas is
generated within the cell. This creates a
rapid-disassembly hazard
(the battery ruptures). If the cell is allowed to over-discharge (V
cell
less than approximately 2.3 V), then the copper metal from the
cathode goes into the electrolyte solution. This shortens the cycle
life of the cell, but presents no safety hazard. If the cell experiences
excessive charge or discharge currents, as happens if the wrong
charger is used, or if the terminals short circuit, the internal series
resistance of the cell creates heating and generates the volatile gas
which could rupture the battery.
The protection circuit continuously monitors the cell voltage for an
overcharged condition
or an
overdischarged condition.
It also
continuously monitors the output for an
overcurrent condition.
If
any of these conditions are encountered, the protection circuit opens
a series MOSFET switch to terminate the abnormal condition. The
lithium cell protection circuit is placed within the battery pack very
close to the cell.
Charging control versus battery protection
The battery pack industry does not recommend using the pack’s
internal protection circuit to end the charging process. The external
battery charger should have a charge termination circuit in it, such
as that provided by the SA57611. This provides two levels of
overcharge protection, with the primary protection of the external
charge control circuit and the backup protection from the battery
pack’s protection circuit. The charge termination circuit will be set to
stop charging at a level around 50 mV less than the overvoltage
threshold voltage of the battery pack’s own protection circuit.
Lithium cell operating characteristics
The internal resistance of lithium cells is in the 100 mΩ range,
compared to the 5–20 mΩ of the nickel-based batteries. This makes
the Lithium-ion and polymer cells better for lower battery current
applications (less than 1 ampere) as found in cellular and wireless
telephones, palmtop and laptop computers, etc.
The average operating voltage of a lithium-ion or polymer cell is
3.6 V as compared to the 1.2 V of NiCd and NiMH cells. The typical
discharge curve for Lithium cell is shown in Figure 3.
OPEN-CIRCUIT CELL VOLTAGE (V)
4.0
V
OV
3.0
V
UV
2.0
50
NORMALIZED CELL CAPACITY (%)
100
SL01553
Figure 3. Lithium discharge curve.
2001 Oct 03
5
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