WD3119
WD3119
High Efficiency, 40V Step-Up White LED
Driver
Http//:www.sh-willsemi.com
Descriptions
The WD3119 is a constant current, high efficiency LED
driver. Internal MOSFET can drive up to 10 white LEDs
in series and 3S9P LEDs with 1.2A current limit and
40V OVP. A Pulse-Width-Modulation (PWM) signal can
be applied to the EN pin for LED dimming. The device
SOT-23-6L / TSOT-23-6L
operates with 1MHz fixed switching frequency to
reduce output ripple, improve conversion efficiency,
and allows using small external components.
6 VIN
LX 1
The WD3119 is available in SOT-23-6L package and
TSOT-23-6L Package. Standard product is Pb-free and
5 OVP
GND 2
Halogen-free.
FB 3
Features

Input voltage range
: 3~5.5V

Open LED Protection
: 43V (Typ.)

Reference Voltage
: 200mV (Typ.)

Switching frequency
: 1MHz (Typ.)

Efficiency
: Up to 92%

Main switch current limit
: 1.2A (Typ.)

PWM Dimming frequency
: (5KHz to200KHz)
Pin configuration (Top view)
6
Smart Phones

Tablets

Portable games
5
4
6
5
3119
YYWW
Applications

4 EN
1
4
3119
FCYW
2
3
1
SOT-23-6L
2
3
TSOT-23-6L
3119 = Device code
3119 = Device code
YY = Year code
FC = Package Code
WW = Week code
Y = Year code
W
= Week code
Marking
Order information
Will Semiconductor Ltd.
1
Device
Package
Shipping
WD3119E-6/TR
SOT-23-6L
3000/Reel&Tape
WD3119F-6/TR
TSOT-23-6L
3000/Reel&Tape
Aug, 2014 - Rev. 1.9
WD3119
Typical applications
D1
WSB5503W
L1
10uH~22uH
VIN
COUT
50V/1uF
CIN
2.2uF
6 VIN
VOUT
LX 1
4 EN
OVP 5
WD3119
FB 3
2 GND
RSET
Pin descriptions
Symbol
Pin No.
Descriptions
LX
1
Switch Output
GND
2
Ground
FB
3
Feedback
EN
4
Enable, Active High
OVP
5
OVP Pin, Connect to VOUT
VIN
6
Power Supply
Block diagram
OVP
Current
Sense
OVP
LX
PWM
COMP
VIN
PWM
Logic
UVLO
Chip Enable
Bandgap
Reference
I SENSE
200mV
EN
PWM
Dimming
Logic
Will Semiconductor Ltd.
OCP
OSC
1.2A
1MHz
FB
Low-Pass
Filter
VREF
Thermal
Shutdown
Gate
Driver
EA
VREF
Soft
Start
GND
2
Aug, 2014 - Rev. 1.9
WD3119
Absolute maximum ratings
Parameter
Symbol
Value
Unit
VIN pin voltage range
VIN
-0.3～6.5
V
OVP pin voltage range
VOVP
-0.3～46
V
EN pin voltage range
-
-0.3～VIN
V
LX pin voltage range (DC)
-
-0.3～46
V
0.5
W
Power Dissipation – SOT-23-6L (Note 1)
PD
Power Dissipation – SOT-23-6L (Note 2)
Junction to Ambient Thermal Resistance – SOT-23-6L (Note 1)
Junction to Ambient Thermal Resistance – SOT-23-6L (Note 2)
Junction temperature
RθJA
TJ
Lead temperature(Soldering, 10s)
TL
Operation temperature
Topr
Storage temperature
Tstg
0.3
W
250
o
416
o
C/W
C/W
150
o
260
o
-40 ~ 85
o
-55 ~ 150
o
C
C
C
C
These are stress ratings only. Stresses exceeding the range specified under “Absolute Maximum Ratings”
may cause substantial damage to the device. Functional operation of this device at other conditions beyond
those listed in the specification is not implied and prolonged exposure to extreme conditions may affect device
reliability.
Note 1: Surface mounted on FR-4 Board using 1 square inch pad size, dual side, 1oz copper
Note 2: Surface mounted on FR-4 board using minimum pad size, 1oz copper
Will Semiconductor Ltd.
3
Aug, 2014 - Rev. 1.9
WD3119
Electronics Characteristics (Ta=25oC, VIN=3.7V, VEN=VIN, CIN=COUT=1uF, unless otherwise noted)
Parameter
Symbol
Operation Voltage Range
VIN
Under Voltage Lockout
VUVLO
Over-Voltage Threshold
VOVP
UVLO Hysteresis
VUVLO-HYS
Quiescent Current
IQ
No Switching
0.3
1
mA
Supply Current
IS
Switching
1.5
3
mA
Shutdown Current
ISD
VEN < 0.4V
1
μA
Operation Frequency
fOSC
0.8
1
1.2
MHz
Maximum Duty Cycle
DMAX
90
92
PWM Dimming Clock Rate
Test Condition
VIN Rising
PWM Dimming Duty Cycle
VREF
On Resistance
RON
Current Limit
ILIM
EN Threshold Voltage
Typ
Max
Units
3
--
5.5
V
1.8
2.2
2.5
V
40
43
46
V
0.1
Recommended
Feedback Reference
Min
V
%
5
200
KHz
3
100
%
215
mV
185
ILX=100mA
200
0.5
Ω
1.2
A
VENL
0.4
VENH
1.5
V
V
EN Sink Current
IEN
3
μA
Thermal Shutdown Temperature
TSD
160
°C
TSD Hysteresis
TSD-HYS
30
°C
Shutdown Delay
tSHDN
1
ms
Will Semiconductor Ltd.
4
Aug, 2014 - Rev. 1.9
WD3119
o
100
100
90
90
80
80
Efficiency(%)
Efficiency(%)
Typical Characteristics (Ta=25 C, unless otherwise noted)
70
60
70
60
8LED
VIN=3.6V L=22uH
VIN=4.2V L=22uH
VIN=5V L=22uH
50
40
0
5
10LED
VIN=3.6V L=22uH
VIN=4.2V L=22uH
VIN=5V L=22uH
50
40
10 15 20 25 30 35 40 45 50
0
100
90
90
80
80
Efficiency(%)
Efficiency(%)
100
70
60
40
70
60
3S9P LED
VIN=3.6V L=10uH
VIN=4.2V L=10uH
VIN=5V L=10uH
0
50
20.8
18
20.6
16
LED Current(mA)
LED Current(mA)
20
20.4
20.2
20.0
19.8
19.6
ILED=20mA
6LED
8LED
10LED
3.0
3.5
4.0
4.5
5.0
4.5
5.0
5.5
14
12
10
8
6
10LED, f=100k, Rset=10
Vin=3.6V
Vin=4.2V
Vin=5V
4
2
0
10
5.5
20
30
40
50
60
70
80
90
Duty(%)
LED Current vs. PWM Duty
Supply Voltage(V)
LED Current vs. Supply Voltage
Will Semiconductor Ltd.
4.0
Efficency vs. Supply Voltage
21.0
19.0
2.5
3.5
Supply Voltage (V)
Output Current (mA)
Efficency vs. Output Current
19.2
3S9P LED, L=10uH
IOUT=180mA
40
3.0
20 40 60 80 100 120 140 160 180 200
19.4
10 15 20 25 30 35 40 45 50
Output Current (mA)
Efficency vs. Output Current
Output Current (mA)
Efficency vs. Output Current
50
5
5
Aug, 2014 - Rev. 1.9
2.0
2.0
1.8
1.8
1.6
1.6
LED Current(mA)
LED Current(mA)
WD3119
1.4
1.2
1.0
0.8
0.6
10LED, Rset=10, f=100k
Vin=3.6V
Vin=4.2V
Vin=5V
0.4
0.2
0.0
1
2
3
4
5
6
7
8
9
1.4
1.2
1.0
0.8
10LED, Rset=10, Vin=3.6V
f=10k
f=100k
f=200k
0.6
0.4
0.2
0.0
10
1
LED Current(mA)
20.6
20.4
20.2
20.0
19.8
10LED，L=10uH，Rset=10 
VIN=3V
VIN=3.6V
VIN=4.2V
VIN=5V
19.6
19.4
19.2
-25
0
25
50
75
Enable Threshold(V)
20.8
5
6
7
8
9
10
1.1
1.0
0.9
0.8
0.7
0.5
2.5
2.2
0.34
2.0
Supply Current(mA)
0.36
0.32
0.30
0.28
0.26
3.5
4.0
4.5
5.0
3.5
4.0
4.5
5.0
5.5
5.5
1.8
1.6
1.4
1.2
1.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
Supply Voltage(V)
Supply Current vs. Supply Voltage
Supply Voltage(V)
Quiesscent Current vs. Supply Voltage
Will Semiconductor Ltd.
3.0
Supply Voltage(V)
Enable Threshold Voltage vs. Supply Voltage
Temperature( C)
LED Current vs. Temperature
3.0
Rising
Falling
0.6
100
O
Quiesscent Current(mA)
4
1.2
21.0
0.24
2.5
3
Duty(%)
LED Current vs. PWM Duty
Duty(%)
LED Current vs. PWM Duty
19.0
-50
2
6
Aug, 2014 - Rev. 1.9
WD3119
1.20
1.20
10LED
ILED=20mA
1.15
1.10
Frequency(KHz)
Frequency(MHz)
1.10
1.05
1.00
0.95
0.90
1.05
1.00
0.95
0.90
0.85
0.85
0.80
2.5
10LED
VIN=3V
VIN=3.6V
VIN=4.2V
VIN=5V
1.15
3.0
3.5
4.0
4.5
5.0
5.5
0.80
-50
0
25
50
75
100
O
Supply Voltage(V)
Frequency vs. Supply Voltage
Temperature( C)
Frequency vs. Temperature
Start-Up from EN
Shutdown from EN
Switching Waveform
Will Semiconductor Ltd.
-25
PWM Dimming
7
Aug, 2014 - Rev. 1.9
WD3119
Operation Information
Normal Operation
Once output voltage goes over the OVP threshold,
LX pin stops switching and the N-MOSFET will be
The WD3119 is a high efficiency, high output
turned off. Then, the output voltage will be clamped
voltage boost converter. The device is ideal for
to be near OVP. Until the OVP eliminate the
driving white LED. The LED connection provides
N-MOSFET will be turned on.
even illumination by sourcing the same output
current through all LEDs. The device integrates
UVLO Protection
40V/1.2A switch FET and operates in pulse width
To avoid malfunction of the WD3119 at low input
modulation (PWM) with 1MHz fixed switching
voltages, an under voltage lockout is included that
frequency. The beginning of each cycle turns on the
disables the device, until the input voltage exceeds
Power MOSFET. A slope compensation ramp is
2.2V (Typ.).
added to the current sense amplifier and the result
is fed into the positive input of the comparator
Shutdown Mode
(COMP). When this voltage goes above the output
Drive EN to GND to place the WD3119 in shutdown
voltage of the error amplifier (EA), the Power
mode. In shutdown mode, the reference, control
MOSFET is turned off. The FB voltage can be
circuit, and the main switch turn off. Input current
regulated to the reference voltage of bandgap with
falls to smaller than 1μA during shutdown mode.
EA block. The feedback loop regulates the FB pin to
a low reference voltage (200mV typical), reducing
the power dissipation in the current sense resistor.
Over-Temperature-Protection (OTP)
As soon as the junction temperature (TJ) exceeds
o
Soft-Start
160 C (Typ.), the WD3119 goes into thermal
shutdown. In this mode, the main N-MOSFET is
The WD3119 Build-in Soft-Start function limits inrush
turned off until temperature falls below typically
current while the device turn-on.
130 C. Then the device starts switching again.
o
Cycle-by-Cycle Current Limit
The WD3119 uses a cycle-by-cycle current limit
circuitry to limit the inductor peak current in the
event of an overload condition. The current flow
through inductor in charging phase is detected by a
current sensing circuit. As the value comes across
the current limiting threshold the N- MOSFET turns
off, so that the inductor will be forced to leave
charging stage and enter in discharging stage.
Therefore, the inductor current will not increase over
the current limiting threshold.
Over-Voltage-Protection (OVP)
The Over Voltage Protection is detected by OVP
block, prevents IC damage as the result of white
LED disconnection.
Will Semiconductor Ltd.
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Aug, 2014 - Rev. 1.9
WD3119
Application Information
External component selection for the application
circuit depends on the load current requirements.
Certain trade-offs between different performance
parameters can also be made.
LED Current Setting
The loop of Boost structure will keep the FB pin
voltage equal to the reference voltage VREF.
Therefore, when RSET connects FB pin and GND,
the current flows from VOUT through LED and RSET to
Figure1
GND will be decided by the current on RSET, which is
equal to following equation:
ILED =
VFB
200mV
=
RSET
RSET
Where
ILED = output current of LEDs
VFB = regulated voltage of FB
RSET = current sense resistor
The output current tolerance depends on the FB
accuracy and the current sensor resistor accuracy.
Therefore, although a PWM signal is applied for
dimming, but only the WLED DC current is
modulated. This help to eliminate the audible noise
which often occurs when the LED current is pulsed
in replica of the frequency and the duty cycle of
PWM control. The minimum dimming frequency is
limited by EN shutdown delay time. For optimum
performance, recommend to select PWM dimming
frequency in the range of 5kHz~200kHz.
The EN shutdown delay time is set to 1ms. This
Dimming Control
For the brightness dimming control of the WD3119,
means the IC needs to be shutdown by pulling the
EN low for 1ms.
the IC provides typically 200mV feedback voltage
when the EN pin is pulled constantly high. However,
EN pin allows a PWM signal to reduce this
regulation voltage by changing the PWM duty cycle
to achieve LED brightness dimming control.
As shown in Figure 1, the duty cycle of the PWM
signal is used to chop the internal 200mV reference
voltage. An internal low pass filter is used to filter the
pulse signal. And then the reference voltage can be
made by connecting the output of the filter to the
error amplifier for the FB pin voltage regulation.
Will Semiconductor Ltd.
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Aug, 2014 - Rev. 1.9
WD3119
Applications for Driving 3S9P LEDs
Input Capacitor Selection
The WD3119 can drive different WLEDs topology.
Connect the input capacitance from VIN to the
For example, the Figure 6 shows the 3S9P WLEDs
reference ground plane. Input capacitance reduces
and total current is equal to 180mA. The total
the ac voltage ripple on the input rail by providing a
WLEDs current can be set by the RSET which is
low-impedance path for the switching current of the
equal to following equation.
boost converter. The capacitor in the range of 1μF
ITotal =
to 10μF / X7R or X5R is recommended for input
VREF
RSET
side.
Output Capacitor Selection
D1
WSB5509L
L1
4.7uH~10 uH
VOUT
VIN
CIN
10uF
COUT
1uF
6
requirements for the output ripple and loop stability.
This ripple voltage is related to the capacitor’s
LX 1
VDD
The output capacitor is mainly selected to meet the
capacitance and its equivalent series resistance
FB
.
GND
OVP
5
.
2
WD3119
.
4 EN
(ESR). The recommended minimum capacitors on
3
3S9P WLEDs
RSET
Output is 1uF/50V, X5R or X7R ceramic capacitor.
Diode Selection
The rectifier diode supplies current path to the
inductor when the internal MOSFET is off. Use a
Boost Inductor Selection
The selection of the inductor affects steady state
operation as well as transient behavior and loop
stability. Inductor values can have ±20% tolerance
with no current bias. When the inductor current
approaches saturation level, its inductance can
decrease 20% to 35% from the 0A value depending
on how the inductor vendor defines saturation
current. Using an inductor with a smaller inductance
value forces discontinuous PWM when the inductor
current ramps down to zero before the end of each
switching cycle. This reduces the boost converter’s
schottky with low forward voltage to reduce losses.
The diode should be rated for a reverse blocking
voltage greater than the output voltage used. The
average current rating must be greater than the
maximum load current expected, and the peak
current rating must be greater than the peak
inductor current.
Diode the following requirements:
● Low forward voltage
● High switching speed
: 50ns max.
● Reverse voltage
: VOUT + VF or more
● Rated current
: IPK or more
maximum output current, causes large input voltage
ripple and reduces efficiency. Large inductance
value provides much more output current and higher
conversion efficiency. The inductor should have low
core loss at 1MHz and low DCR for better efficiency.
For these reasons, the recommended value of
inductor for 10 series WLEDs applications is from
10μH to 22μH. A 22μH inductor optimized the
efficiency for most application while maintaining low
inductor peak to peak ripple. A 4.7μH to 10μH boost
inductor is recommended in 3S9P LED application.
Will Semiconductor Ltd.
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Aug, 2014 - Rev. 1.9
WD3119
PCB Layout Considerations
A good circuit board layout aids in extracting the
most performance from the WD3119. Poor circuit
layout
degrades
electromagnetic
the
output
interference
ripple
(EMI)
and
or
the
electro-
magnetic compatibility (EMC) performance. The
evaluation board layout is optimized for the WD3119.
Use this layout for best performance. If this layout
needs changing, use the following guidelines:
1.
Use separate analog and power ground planes.
Connect the sensitive analog circuitry (such as
voltage divider components) to analog ground;
connect the power components (such as input
and output bypass capacitors) to power ground.
Connect the two ground planes together near
the load to reduce the effects of voltage
dropped on circuit board traces. Locate CIN as
close to the VIN pin as possible, and use
separate input bypass capacitors for the
analog.
2.
Route the high current path from CIN, through L
WD3119 PCB Suggest Layout (Demo)
to the LX and GND pins as short as possible.
3.
Keep high current traces as short and as wide
as possible.
4.
The output filter of the boost converter is also
critical for layout. The Diode and Output
capacitors should be placed to minimize the
area of current loop through Output –GND–LX.
5.
Avoid routing high impedance traces, such as
Output, near the high current traces and
components or near the Diode node.
6.
If high impedance traces are routed near high
current and/or the LX node, place a ground
plane shield between the traces.
Will Semiconductor Ltd.
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Aug, 2014 - Rev. 1.9
WD3119
Package outline dimensions
SOT-23-6L
Symbol
Dimensions in millimeter
Min.
Typ.
Max.
A
1.050
-
1.250
A1
0.000
-
0.100
A2
1.050
-
1.150
b
0.300
-
0.500
c
0.100
-
0.200
D
2.820
2.900
3.020
E
1.500
1.600
1.700
E1
2.650
2.800
2.950
e
0.950(BSC)
e1
1.800
-
2.000
L
0.300
-
0.600
θ
0°
-
8°
Will Semiconductor Ltd.
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Aug, 2014 - Rev. 1.9
WD3119
Package outline dimensions
TSOT-23-6L
Symbol
Dimensions in millimeter
Min.
Typ.
Max.
A
-
-
0.900
A1
0.000
-
0.100
A2
0.700
-
0.800
b
0.350
-
0.500
c
0.080
-
0.200
D
2.820
2.900
3.020
E1
1.600
1.650
1.700
E
2.650
2.800
2.950
e
0.950 (BSC)
e1
1.900 (BSC)
L
0.300
-
0.600
θ
0°
-
8°
Will Semiconductor Ltd.
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Aug, 2014 - Rev. 1.9