NJW4617
Constant Current LED Driver with PWM Dimming Control
■ GENERAL DESCRIPTION
The NJW4617 is a constant current LED driver with PWM dimming
control. The output current can be set by external sensing resister,
and the NJW4617 can set up to 500mA.
Because the withstand voltage of the output (LED) pin is 40V, it
can series-connect the LED depending on forward voltage of the
LED. The LED dimming control can be regulated via PWM duty
cycle. It is suitable for back light, light source and so on.
■ PACKAGE OUTLINE
NJW4617DL3
(TO-252-5)
■ FEATURES
▪ Operating Voltage Range:
2.5V to 40V
▪ Output Voltage:
VLED=40V max.
▪ Output Current:
ILED=20mA to 500mA
▪ Output Current Accuracy:
1.5%
▪ To 11 of White LED can be operated. (at LED Vf=3.4V)
▪ Quiescent Current:
450µA max.
▪ PWM Dimming Control and Enable Control (Common Pin)
▪ Over Current Protection
▪ Thermal Shutdown Protection
▪ LED Short Protection
▪ Package:
TO-252-5
■ BLOCK DIAGRAM
VDD
LED
+
VREF
(0.2V)
RS
Current Limit
Thermal Shut Down
LED Short Protection
Control
Logic
Standby Timer
GND
Ver.2020-06-11
EN/PWM
-1-
NJW4617
■ PIN CONFIGURATION
5. LED
4. RS
3. GND
2. EN/PWM
1. VDD
■ PIN DESCRIPTIONS
Pin No.
Pin Name
1
VDD
I/O
-
2
EN/PWM
I
3
GND
-
4
RS
O
5
LED
O
-2-
Function
Power supply pin
Standby control pin and PWM signal input pin for dimming control.
[At Standby control]
Normal operation: High Level.
Standby mode: Low Level.
[At PWM signal input]
The LED dimming control can be regulated by PWM duty cycle.
In the case without dimming, ILED becomes the current set by the external resistor
(Rs) when High level is input to this pin.
Note that this pin should not be open.
Ground pin
Resistor connect pin of ILED setting.
The LED current can be set with connected resistor (RS) between RS pin and GND
pin. RS [Ω] = 0.2 [V] / ILED [A]
Constant current circuit output pin
Connect cathode pin of LED.
Ver.2020-06-11
NJW4617
■ ABSOLUTE MAXIMUM RATINGS
PARAMETER
SYMBOL
Supply Voltage
VDD
Output Voltage
VLED
EN/PWM Pin Voltage
VENPWM
Power Dissipation
PD
Junction Temperature Range
Operating Temperature Range
Storage Temperature Range
Tj
Topr
Tstg
RATINGS
-0.3 to +45
-0.3 to +45
-0.3 to +45
1190 (*1)
3125 (*2)
-40 to +150
-40 to +125
-50 to +150
(Ta = 25C)
UNIT
V
V
V
mW
C
C
C
2
(*1) Mounted on glass epoxy board. (76.2 × 114.3 × 1.6mm: based on EIA/JEDEC standard size, 2Layers, Cu area 100mm )
(*2) Mounted on glass epoxy board. (76.2 × 114.3 × 1.6mm: based on EIA/JEDEC standard, 4Layers),
(For 4Layers: Applying 74.2 × 74.2mm inner Cu area and a thermal via hole to a board based on JEDEC standard JESD51-5)
■ RECOMMENDED OPERATING CONDITIONS
PARAMETER
SYMBOL
Supply Voltage
VDD
Output Current
ILED
Output Voltage
VLED
TEST CONDITIONS
MIN.
2.5
20
-
TYP.
-
MAX.
40
500
40
UNIT
V
mA
V
■ ELECTRICAL CHARACTERISTICS
(Unless otherwise noted, VDD = 12V, VLED = 1V, RS = 2Ω, VENPWM = VDD, Ta = 25C )
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
TYP MAX Unit
Quiescent Current
IDD
330
450
µA
Quiescent Current at OFF State
IDD_OFF
VENPWM = GND
0.1
µA
Output Current Accuracy
-1.5
+1.5
%
ILED
Output (LED) Pin Leak Current
ILEAK
VENPWM = GND, VDD = VLED = 40V
0.1
µA
OFF Delay Time
tD_OFF
10
25
45
ms
V
EN/PWM Pin ON Voltage1
VENPWM_ON1 VDD < 5V, ILED = OFF ON
0.7VDD
VDD
EN/PWM Pin ON Voltage2
VENPWM_ON2 VDD ≥ 5V, ILED = OFF ON
3.5
VDD
V
V
EN/PWM Pin OFF Voltage
VENPWM_OFF ILED = ON OFF
0
0.5
EN/PWM Pin Input Current
IENPWM
7
µA
RS Pin Output Current
IOUT_RS
LED = OPEN
4
µA
PWM Dimming ON Delay Time
tPWM_ON
13
µs
RS = 0.4Ω, VENPWM = L H
PWM Dimming OFF Delay Time
tPWM_OFF
1
µs
RS = 0.4Ω, VENPWM = H L
LED Short Protection
VLED_SHORT
18
21
24
V
Detect Voltage
Maximum Output Current
ILED_MAX
RS = 0Ω
500
850
mA
Ver.2020-06-11
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NJW4617
■ TYPICAL APPLICATION
VDD / V+
(*3)
VDD
LED
ILED
+
VREF
(0.2V)
Current Limit
Thermal Shut Down
LED Short Protection
H : ON
L : OFF
PWM : Dimming
Control
ILED
RS
Control
Logic
0
Output Current Wave Form
at PWM Dimming
RS : Current Sense Resistor
Standby Timer
GND
EN/PWM
The Rs Resistance Setting formula: RS ( )
0.2(V )
ILED ( A)
(*3) If the wiring from the power supply to the LED anode pin is long, the voltage may change due to the influence of the
parasitic elements.
As the countermeasure, it should connect a decoupling capacitor as close to the LED as possible.
-4-
Ver.2020-06-11
NJW4617
■ TYPICAL CHARACTERISTICS
Quiescent Current vs. Supply Voltage
Quiescent Current vs. Temperature
[VLED=1V, VENPWM=VDD, RS=2Ω]
450
400
400
Quiescent Current : IDD [μA]
Quiescent Current : IDD [μA]
[VDD=12V, VLED=1V, VENPWM=VDD, RS=2Ω]
450
350
300
250
200
150
100
-40℃
25℃
50
350
300
250
200
150
100
50
125℃
150℃
0
0
0
10
20
30
Supply Voltage : VDD [V]
-50
40
-25
0
25 50 75 100 125 150
Temperature : [ºC]
Quiescent Current at OFF State : IDD_OFF [nA]
Quiescent Current at OFF State vs. Temperature
[VLED=1V, VENPWM=GND, RS=2Ω]
100
VDD=2.5V
VDD=12V
10
VDD=40V
1
0.1
-50
-25
0
25 50 75 100 125 150
Temperature : [ºC]
Output Pin Leak Current vs. Temperature
1000
40
VLED=1V
VLED=5V
100
[VDD=12V, VLED=1V]
45
OFF Delay Time : tD_OFF [ms]
Output Pin Leak Current : ILEAK [nA]
OFF Delay Time vs. Temperature
[VDD=40V, VLED=40V, VENPWM=GND, RS=2Ω]
VLED=40V
10
1
35
30
25
20
15
10
5
0
0.1
-50
Ver.2020-06-11
-25
0
25 50 75 100 125 150
Temperature : [ºC]
-50
-25
0
25 50 75 100 125 150
Temperature : [ºC]
-5-
NJW4617
■ TYPICAL CHARACTERISTICS
EN/PWM Pin ON Voltage vs. Temperature
[VLED=1V, RS=2Ω]
EN/PWM Pin ON Voltage : VENPWM_ON [V]
EN/PWM Pin ON Voltage : VENPWM_ON [V]
EN/PWM Pin ON Voltage vs. Supply Voltage
3
2.5
2
1.5
1
-40℃
0.5
25℃
125℃
150℃
0
0
10
20
30
Supply Voltage : VDD [V]
2.5
2
1.5
1
0.5
0
-50
40
3
2.5
2
1.5
1
-40℃
25℃
0.5
125℃
150℃
0
0
10
20
30
Supply Voltage : VDD [V]
40
-25
0
25 50 75 100 125 150
Temperature : [ºC]
EN/PWM Pin OFF Voltage vs. Temperature
EN/PWM Pin OFF Voltage : VENPWM_OFF [V]
EN/PWM Pin OFF Voltage : VENPWM_OFF [V]
EN/PWM Pin OFF Voltage vs. Supply Voltage
[VLED=1V, RS=2Ω]
[VDD=12V, VLED=1V, RS=2Ω]
3
[VDD=12V, VLED=1V, RS=2Ω]
3
2.5
2
1.5
1
0.5
0
-50
-25
0
25 50 75 100 125 150
Temperature [ºC]
EN/PWM Pin Input Current : IENPWM [μA]
EN/PWM Pin Input Current vs. EN/PWM Pin Voltage
[VDD=VENPWM, VLED=1V, RS=2Ω]
60
-40℃
25℃
50
125℃
150℃
40
30
20
10
0
0
-6-
10
20
30
EN/PWM Pin Voltage : VENPWM [V]
40
Ver.2020-06-11
NJW4617
■ TYPICAL CHARACTERISTICS
PWM Dimming ON Delay Time vs. Output Current
18
16
14
12
10
8
6
4
2
0
0
100
200
300
400
Output Current : ILED [mA]
500
PWM Dimming OFF Delay Time vs. Output Current
PWM Dimming OFF Delay Time : tPWM_OFF [μs]
PWM Dimming ON Delay Time : tPWM_ON [µs]
[VDD=12V, VLED=1V]
20
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
0
30
RS=10Ω
25
RS=2Ω
RS=0.4Ω
20
15
10
5
0
-50
-25
0
25 50 75 100 125 150
Temperature : [ºC]
100
200
300
400
Output Current : ILED [mA]
[VDD=12V, VLED=1V]
1.4
RS=10Ω
1.2
RS=2Ω
1
RS=0.4Ω
0.8
0.6
0.4
0.2
0
-50
-25
Output Current vs. Output Pin Voltage
0
25 50 75 100 125 150
Temperature : [ºC]
Output Current vs. Temperature
[VDD=12V, VENPWM=VDD]
600
500
PWM Dimming OFF Delay Time vs. Temperature
PWM Dimming OFF Delay Time : tPWM_OFF [μs]
PWM Dimming ON Delay Time : tPWM_ON [μs]
PWM Dimming ON Delay Time vs. Temperature
[VDD=12V, VLED=1V]
[VDD=12V, VLED=1V]
5
[VDD=12V, VLED=1V, RS=2Ω, VENPWM=VDD]
110
108
RS=2Ω
500
Output Current : ILED [mA]
Output Current : ILED [mA]
RS=10Ω
RS=0.667Ω
RS=0.4Ω
400
300
200
100
106
104
102
100
98
96
94
92
0
90
0
Ver.2020-06-11
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Output Pin Voltage : VLED [V]
1
-50 -25
0
25 50 75 100 125 150 175 200
Temperature : [ºC]
-7-
NJW4617
■ TYPICAL CHARACTERISTICS
Maximum Output Current vs. Output Pin Voltage
LED Short Protection Voltage vs. Temperature
LED Short Protection Voltage :
VLED_SHORT/OFF [V]
Detect Voltage
23
Release Voltage
22
21
20
19
18
17
16
15
-50
-25
0
Maximum Output Current : ILED_MAX [mA]
[VDD=12V, VENPWM=VDD, RS=0Ω]
24
700
600
500
400
300
200
100
0
0
600
500
400
300
40
[VDD=12V, VENPWM=VDD, VLED=1V]
1000
Output Current : ILED [mA]
Maximum Output Current : ILED_MAX [mA]
700
10
20
30
Output Pin Voltage : VLED [V]
Output Current vs. Current Sense Resistance
[VDD=12V, VLED=1V, VENPWM=VDD, RS=0Ω]
800
Detect Voltage
800
25 50 75 100 125 150
Temperature : [ºC]
900
Release Voltage
900
Maximum Output Current vs. Temperature
1000
[VDD=12V, VENPWM=VDD, RS=0Ω]
1000
100
200
100
0
10
-50
-8-
-25
0
25 50 75 100 125 150
Temperature : [ºC]
0.1
1
10
Current Sense Resistance : RS [Ω]
100
Ver.2020-06-11
NJW4617
Application Manual
■ The number of LED series connection
It is necessary to drive LED that is the LED forward voltage (Vf) or more.
When the LED was series connected, the supply voltage should be input sum of LED Vf (ΣLED Vf) the series
connected or more. In NJW4617, it is necessary as minimum V+ that is ΣLED Vf + NJW4617 output voltage (VLED =
1V). The maximum LED connected number that NJW4617 can drive is limited by the recommended output voltage
maximum value (40V). Moreover, it should be used with ΣLED Vf within 39V that is subtracted the VLED = 1V.
The table below shows maximum LED number at each Vf. (All LED Vf assumes ideally same)
LED Vf is up to 3.0V
▪▪▪
up to 13 lights
LED Vf is up to 3.2V
▪▪▪
up to 12 lights
LED Vf is up to 3.5V
▪▪▪
up to 11 lights
LED Vf is up to 3.9V
▪▪▪
up to 10 lights
LED Vf is up to 4.3V
▪▪▪
up to 9 lights
V+ 40V
VDD
(*4)
(*3)
Vf n pcs. = LEDVf 39V
VDD
LED
+
VREF
(0.2V)
Current Limit
Thermal Shut Down
LED Short Protection
RS
Control
Logic
Standby Timer
GND
EN/PWM
(*4) If the wiring from the power supply to the VDD pin is long, the voltage may change due to the influence of the parasitic
elements.
As the countermeasure, it should connect a decoupling capacitor as close to the VDD pin as possible.
Ver.2020-06-11
-9-
NJW4617
Application Manual
■ PWM input pulse and PWM dimming accuracy
The ILED transient behavior corresponding to PWM input pulse has some delay at rise/fall time.
PWM Input Pulse
Output Current Pulse
tPWM_ON
tPWM_OFF
Output Current PWM ON/OFF Propagation Delay
( Output Current Pulse Width Error : εt = tPWM_ON - tPWM_OFF)
If enter a PWM signal with short pulse width, for the output current pulse width error becomes larger against the
PWM input pulse width, it is incapable of accurate PWM dimming. The Output current pulse width error rate (εt)
becomes the following value. ( εt=tPWM_ON –tPWM_OFF )
εt = approx. 12µs (Output Current: ILED=500mA,Ta=25C typ. )
The actual value of the output current pulse width error rate can calculate by above error rate (εt) and the
frequency and Duty of the PWM input pulse. (fPWM: PWM input pulse frequency, D: PWM input pulse Duty)
Based on the allowable value of the output current pulse width error rate, you should determine the frequency and
Duty of the PWM input pulse.
PWM Input pulse width
= D / 100 × ( 1 / fPWM )
Output Current pulse width
= PWM Input pulse width - εt
Output Current pulse width error rate
= (Output Current pulse width - PWM Input pulse width) / PWM Input pulse width × 100
= -εt / PWM Input pulse width × 100 [%]
【 Output current pulse width error rate calculation example:
operation with PWM input pulse frequency 200Hz and Duty1% 】
PWM Input pulse width
= 1 [%] / 100 × ( 1 / 200[Hz] ) = 50 [µs]
Output Current pulse width error rate = -12 [µs] / 50 [µs] × 100
= -24 [%]
Output Current Duty vs. PWM Input Pulse Duty
【 Measurement Conditions 】
100
ILED=20mA
Output Current (ILED)
Output Current Duty [%]
ILED=100mA
ILED=500mA
10
1
20mA
(RS = 10Ω)
100mA
(RS = 2Ω)
500mA
(RS = 0.4Ω)
Supply Voltage
12V
Output (LED) pin
Input Voltage at 1V
PWM Input Pulse
200Hz, 0 to 5V
Output Current ILED Pulse Width The time is more than 90% of set current.
0.1
Ambient Temperature Ta=25ºC
0.01
0.01
- 10 -
0.1
1
10
PWM Input Pulse Duty [%]
100
Ver.2020-06-11
NJW4617
Application Manual
■ Protection Circuit
▪ Over Current Protection (Refer to Maximum Output Current vs. Output Pin Voltage)
This protection function limits the output current, when the RS pin and GND pin was shorted. The limited current is
dependence on output (LED) pin voltage.
When the output (LED) pin voltage is less than "LED Short Protection Detect Voltage", maximum output current is
limited to approx. 850mA (output (LED) pin voltage=1V, Ta=25C).
The output current returns to set current, when the short status is release.
▪ LED Short Protection (Refer to Maximum Output Current vs. Output Pin Voltage)
This protection function limits the output current, when the output (LED) pin rises as in LED shorten at output FET ON.
The output current is limited to approx. 400mA when the output (LED) pin voltage rose to approx. 21V.
▪ Thermal Shutdown Function (Refer to Output Current vs. Temperature)
When junction temperature of the NJW4617 exceeds the 160°C*, internal thermal shutdown circuit function stops the
device function. When junction temperature decreases to 140°C* or less, the device operation returns to normal
operation.
The purpose of this function is to prevent malfunctioning of IC at the high junction temperature. Therefore it is not
something that urges positive use. It should make sure to operate within the junction temperature range rated
(+150°C).
*) Design value
Ver.2020-06-11
- 11 -
NJW4617
Application Manual
■ The Loss of Constant Current Driver
The power consumption of the LED lighting circuit is classified as "the power consumption of the constant current
driver" "the power consumption of the LED" and "the power consumption of the current sense resistor (RS)".
The loss of constant current driver is caused mainly by quiescent current (IDD) and output current (ILED).
The power dissipation of the device can calculate by follow equation.
VDD
V+
(*4)
PD ≈ VDD IDD + (VLED - VRS) ILED
= VDD IDD + (V+ - LED Vf - 0.2) ILED [W]
(*3)
LEDVf
Rs pin voltage (VRS): 0.2V
ΣLED Vf represents the sum of the LED Vf of use.
IDD
VDD
LED
+
VREF
(0.2V)
Current Limit
Thermal Shut Down
LED Short Protection
ILED
VLED - VRS
RS
Control
Logic
e.g.)
VDD = V+ = 12[V], IDD=330[µA], LED Vf = 9[V],
ILED = 400[mA]
PD ≈ 12[V] 330[µA] + (12[V] - 9[V] -0.2[V]) 400[mA]
≈ 1124[mW]
Standby Timer
EN/PWM
GND
As shown in the above equation, the loss of constant current driver will increase in proportion to the voltage difference
between the LED driving voltage V+ and ΣLED Vf.
The device power dissipation must be below the power dissipation rate of the device package including thermal
derating to ensure correct operation. It should set the LED operating Voltage (V+) and output current (ILED) with
consideration of PD.
NJW4617DL3 (TO-252-5)
Power Dissipation
(Topr=-40ºC to +125ºC, Tj=150ºC)
3500
The device power dissipation must be below the power
dissipation rate of the device package including thermal
derating to ensure correct operation.
(*2) on 4 Layers Board
Package Power : Pd [mW]
3000
2500
2000
(*1): Mounted on glass epoxy board. (76.2 × 114.3 × 1.6mm:
1500
(*1) on 2 Layers Board
based on EIA/JEDEC standard size, 2Layers, Cu area 100mm2)
1000
(*2): Mounted on glass epoxy board. (76.2 × 114.3 × 1.6mm:
based on EIA/JEDEC standard, 4Layers),
500
(For 4Layers: Applying 74.2 × 74.2mm inner Cu area and a
0
-50
- 12 -
-25
0
25
50
75
100
Ambient Temperature : Ta [ºC]
125
150
thermal via hole to a board based on JEDEC standard JESD51-5)
Ver.2020-06-11
NJW4617
Application Manual
■ Parallel Drive of NJW4617
For applications that require more than 500mA, it can correspond by parallel connecting two or more NJW4617.
The LED current becomes sum of LED current of each NJW4617.
Each device accepts different set current.
ILED [A] = ILED1 + ILED2 = 0.2 / RS1 [Ω] + 0.2 / RS2 [Ω]
(e.g. ILED = 750 [mA] setting: RS1 = 0.4 [Ω], RS2 = 0.8 [Ω] ）
V+
(*3)
ILED
VDD
(*4)
ILED1
VDD
ILED2
VDD
LED
LED
+
VREF
(0.2V)
Current Limit
Thermal Shut Down
LED Short Protection
+
VREF
(0.2V)
RS
Control
Logic
RS 1
Current Limit
Thermal Shut Down
LED Short Protection
Standby Timer
GND
RS
Control
Logic
RS 2
Standby Timer
EN/PWM
GND
EN/PWM
PWM
Ver.2020-06-11
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NJW4617
MEMO
[CAUTION]
The specifications on this databook are only
given for information, without any guarantee
as regards either mistakes or omissions. The
application circuits in this databook are
described only to show representative usages
of the product and not intended for the
guarantee or permission of any right including the
industrial rights.
- 14 -
Ver.2020-06-11
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