WS4518E
WS4518E
300mA, Single Li-ion Battery Charger
Descriptions
The WS4518E is a complete constant-current /
constant
voltage
linear
charger
for
single
cell
Lithium-Ion batteries. No external sense resistor is
needed, and no blocking diode is required due to the
internal MOSFET architecture. Thermal feedback
regulates
the
charge
current
to
limit
the
die
SOT-23-5L
temperature during high power operation or high
ambient temperature. The charge voltage is fixed at
4.2V, and the charge current can be programmed
externally with a single resistor.
The WS4518E automatically terminates the charge
cycle when the charge current drops to 3/10 the
programmed value after the final float voltage is
reached.
Pin configuration (Top view)
When the input supply (wall adapter or USB supply) is
removed, the WS4518E automatically enters a low
current state, dropping the battery drain current to less
than 0.5uA. The WS4518E can be put into shutdown
mode, reducing supply current to 40uA (Typ.).
4518
The WS4518E is available in a small package with
SOT-23-5L. Standard product is Pb-Free.
EAYW
5
4
CHGb 1
GND 2
BAT 3
4 VCC
5 PROG
Http//:www.sh-willsemi.com
Features
Programmable Charge Current Up to 300mA
Over-Temperature Protection
Under Voltage Lockout Protection
Automatic Recharge Threshold 4.05V(Typ.)
Charge Status Output Pin
2.9V Trickle Charge Threshold
Soft-Start Limits Inrush Current
Device
WS4518E-5/TR
1
4518
EA
Y
W
2
3
= Device Code
= Package Code
= Year
= Week
Marking
Order information
Package
SOT-23-5L
Shipping
3000/Reel&Tape
Applications
Wireless phone
MP3/MP4 Player
Bluetooth device
Will Semiconductor Ltd.
1
Aug, 2014 - Rev. 1.0
WS4518E
Typical applications
VCHG
VIO
680K
1
1K
2
3
Li-ion
Battery
GND
BAT
VCC
4
10uF
CHGb
PROG
5
10K
uP
1
2
3
Li-ion
Battery
CHGb
GND
BAT
PROG 5
10K
VCHG
WS4518E
WS4518E
VCC
4
10uF
Typical applications W/T LED indicate
Typical applications W/T microprocessor detect
Pin descriptions
Pin Number
1
Pin Name
CHGb
Function
Open-Drain Charge Status Output. When the battery is charging, the CHGb
pin is pulled low. When the charge cycle is completed or VCC is removed, the
CHGb is forced high impedance.
2
3
4
5
GND
BAT
VCC
PROG
Ground
Charge Current Output. Provides charge current to the battery and regulates
the final float voltage to 4.2V.
Power Supply
Charge current setting, charge current monitor and shutdown pin. The
charging current is given by I
BAT
= (1/R
PROG
)*1000. The chip will be shutdown
when PROG pin floating
Block Diagram
165°
C
TDIE
VCC
TA
1X
5uA
1000X
BAT
MA
R1
VA
CA
R2
SHDNb
C1
1V
0.3V
R3
R4
REF
1.2V
CHGb
C2
R5
To
BAT
2.9V
1uA
C3
Vcc
PROG
GND
Will Semiconductor Ltd.
2
Aug, 2014 - Rev. 1.0
WS4518E
Absolute Maximum ratings
Parameter
Supply Voltage
PROG Voltage
BAT Voltage
CHGb Voltage
BAT Pin Current
Power Dissipation –
Note1
Power Dissipation –
Note2
Junction Temperature
Operation Temperature
Storage Temperature
Lead Temperature (Soldering 10s)
Symbol
VCC
V
PROG
V
BAT
V
CHGb
I
BAT
Pd
Pd
Tj
Top
Tsg
Rating
-0.3~8
-0.3~VCC
-0.3~8
-0.3~VCC
600
0.5
0.3
150
-45~85
-65~125
260
Unit
V
V
V
V
mA
W
W
o
o
o
o
C
C
C
C
Thermal resistance characteristics
Symbol
R
JA1
R
JA2
Parameter
Thermal Resistance, Junction to Ambient –
Note1
Thermal Resistance, Junction to Ambient –
Note2
Max.
125
415
Unit
O
O
C/W
C/W
Note1:
Surface mounted on FR4 Board using 1 in sq pad size, 2oz Cu.
Note2:
Surface mounted on FR4 board using the minimum recommended pad size, 2oz Cu.
Will Semiconductor Ltd.
3
Aug, 2014 - Rev. 1.0
WS4518E
Electronics Characteristics
(VCC=5V, Ta=25
o
C, unless otherwise noted)
Symbol
Parameter
Condition
Min.
I
SPLYCHRG
I
BATCHRG
V
PROGCHRG
I
SPLYSTBY
I
BATSTBY
I
SPLYASD
I
BATASD
I
SPLYUVLO
I
BATUVLO
I
SPLYSHUT
I
BATSHUT
I
BATMSD
I
BATSLEEP
V
FLOAT
I
TRIKL
V
TRIKL
V
TRIKL, HYS
V
UVLO
V
UVLO, HYS
V
MSD
V
ASD
ΔV
RECHRG
V
CHGb
T
LIM
R
ON
T
SS
T
RECHRG
T
TERM
I
PROG
Charge Mode Supply Current
Charge Mode Battery Current
PROG Pin Voltage
Standby Mode Supply Current
Standby Mode Battery Current
Shutdown Mode Supply Current
Shutdown Mode BAT Pin Current
UVLO Mode Supply Current
UVLO Mode BAT Pin Current
Shutdown Mode Supply Current
Shutdown Mode BAT Pin Current
Manual Shutdown BAT Pin Current
Sleep Mode BAT Pin Current
Float Voltage
Trickle Charge Current
Trickle Charge Voltage Threshold
Trickle Charge Voltage Hysteresis
UVLO Threshold
UVLO Hysteresis
Manual Shutdown Threshold Voltage
Vcc-V
BAT
Lockout Threshold Voltage
Auto Recharge Battery Voltage
CHGb Pin Output Low Voltage
Junction Temperature In Constant
Temperature Mode
Power FET ON Resistance
Soft-Start Time
Recharge Comparator Filter Time
Termination Comparator Filter Time
PROG Pin Pull-up Current
0.7
R
PROG
=2kΩ
I
CHGb=5mA
PROG Pin Rising
PROG Pin Falling
V
CC
from Low to High
V
CC
from High to Low
5
100
R
PROG
=10kΩ
R
PROG
=10kΩ
R
PROG
=10kΩ
From V
CC
Low to High
3.6
R
PROG
=10kΩ
R
PROG
=20kΩ
R
PROG
=10kΩ
R
PROG
=20kΩ
R
PROG
=10kΩ
R
PROG
=20kΩ
Charge Terminated
Charge Terminated
V
CC
<V
BAT
V
CC
<V
BAT
V
CC
<V
UV
V
CC
<V
UV
R
PROG
not Connected
R
PROG
not Connected
V
PROG
=1.3V
V
CC
=0V
4.158
19
2.8
20
20
0
20
0.93
0.93
90
Typ.
220
170
100
50
1.00
1.00
130
-2.5
40
±0.05
40
±0.05
40
±0.05
±0.05
±0.05
4.2
29
2.9
100
3.8
250
1.2
1.0
120
50
150
0.3
165
200
100
2
1
1.1
Max.
2000
2000
110
1.07
1.07
500
-6
90
±1
90
±1
70
±1
±1
±1
4.242
39
3.0
4.0
1.3
Unit
uA
uA
mA
mA
V
V
uA
uA
uA
uA
uA
uA
uA
uA
uA
uA
V
mA
V
mV
V
mV
V
V
mV
mV
200
0.6
mV
V
o
C
mΩ
us
ms
ms
1.5
uA
Will Semiconductor Ltd.
4
Aug, 2014 - Rev. 1.0
WS4518E
Typical Characteristics
(Ta=25
o
C, unless otherwise noted)
1.10
1.08
1.06
1.04
1.02
1.00
0.98
0.96
0.94
0.92
0.90
4.0
4.5
5.0
V
BAT
=4.0V
R
PROG
=10KΩ
R
PROG
=20KΩ
R
PROG
=50KΩ
5.5
6.0
6.5
1.10
1.08
1.06
1.04
V
PROG
( V )
V
PROG
( V )
1.02
1.00
0.98
0.96
0.94
0.92
0.90
-50
-25
0
25
O
V
BAT
=4V
R
PROG
=10KΩ
R
PROG
=20KΩ
R
PROG
=50KΩ
50
75
100
V
CC
( V )
Temperature ( C )
PROG Pin Voltage vs Supply Voltage
PROG Pin Voltage vs Ambient Temperature
110
100
90
80
110
100
90
80
V
BAT
=4.0V
R
PROG
=10KΩ
R
PROG
=20KΩ
R
PROG
=50KΩ
I
BAT
( mA )
60
50
40
30
20
10
0
0.3
0.4
0.5
0.6
0.7
V
CC
= 5 V
R
PROG
= 10K
0.8
0.9
1.0
I
BAT
( mA )
70
70
60
50
40
30
20
10
0
4.0
4.5
5.0
5.5
6.0
V
PROG
( V )
V
CC
( V )
Charge Current vs PROG Pin Voltage
Charge Current vs Supply Voltage
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
0
4.0
3.00
2.95
V
BAT
=2.5V
R
PROG
=10KΩ
R
PROG
=20KΩ
R
PROG
=50KΩ
2.90
I
TRIKL
( mA )
V
TRIKL
( V )
2.85
2.80
2.75
2.70
2.65
R
PROG
=10KΩ
R
PROG
=20KΩ
R
PROG
=50KΩ
4.5
5.0
5.5
6.0
6.5
4.5
5.0
5.5
6.0
6.5
2.60
4.0
V
CC
( V )
V
CC
( V )
Trickle Charge Current vs Supply Voltage
Trickle Voltage vs Supply Voltage
Will Semiconductor Ltd.
5
Aug, 2014 - Rev. 1.0
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