NJW4615A

- 1 - Ver.2017-06-14

Constant Current LED Driver with PWM Dimming Control GENERAL DESCRIPTION PACKAGE OUTLINE

The NJW4615A is a constant current LED driver with PWM dimming control. The output current can be set by external sensing resister, and the NJW4615A can set up to 100mA. Because the withstand voltage of the output (LED) pin is 35V, 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.

FEATURES Supply Voltage Range 2.5V to 35V Output Voltage VLED = 35V max. Output Current ILED = 5mA to 100mA Output Current Accuracy 1.2% To 10 of White LED can be operated. (at LED Vf=3.2V) Quiescent Current 370µA max. PWM Dimming Control Enable Function Over Current Protection (with Hysteresis) Thermal Shutdown Protection LED Short Protection Package SOT-23-6-1 BLOCK DIAGRAM

ControlLogic

Current Limit Thermal Shut Down

LED Short Protection

VREF( 0.2V )

GND EN PWM

RS

VDD

LED

NJW4615AF1 (SOT-23-6-1)

NJW4615A

- 2 - Ver.2017-06-14

PIN CONFIGURATION

PWM 1

GND 2

RS 3 4 LED

5 EN

6 VDD

PIN DESCRIPTIONS

Pin No. Pin Name I/O Function

1 PWM I

PWM signal input pin for dimming control. The LED dimming control can be regulated by PWM duty cycle. When this pin is open or input High level, ILED becomes set current by an external resistor (RS).

2 GND - Ground pin

3 RS O 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]

4 LED O Constant current circuit output pin Connect cathode pin of LED.

5 EN I Standby control pin Normal operation: High Level. Standby mode: Low Level.

6 VDD - Power supply pin

NJW4615A

- 3 - Ver.2017-06-14

ABSOLUTE MAXIMUM RATINGS (Ta=25 C) PARAMETER SYMBOL RATINGS UNIT

Supply Voltage VDD -0.3 to +40 V Output Voltage VLED -0.3 to +40 V EN Pin Voltage VEN -0.3 to +40 V PWM Pin Voltage VPWM -0.3 to +6 V

Power Dissipation PD 510 (*1) 710 (*2) mW

Junction Temperature Range Tj -40 to +150 C Operating Temperature Range Topr -40 to +125 C Storage Temperature Range Tstg -50 to +150 C

(*1) Mounted on glass epoxy board based on EIA/JEDEC. (76.2 × 114.3 × 1.6mm: 2Layers FR-4) (*2) Mounted on glass epoxy board based on EIA/JEDEC. (76.2 × 114.3 × 1.6mm: 4Layers FR-4), Internal Cu area: 74.2 × 74.2mm

RECOMMENDED OPERATING CONDITIONS

PARAMETER SYMBOL TEST CONDITIONS MIN. TYP. MAX. UNIT Supply Voltage VDD 2.5 - 35 V Output Current ILED 5 - 100 mA Output Voltage VLED - - 35 V

ELECTRICAL CHARACTERISTICS

(Unless otherwise noted, VDD= VEN=12V, VLED=1V, RS=10Ω, VPWM=OPEN, Ta=25 C) PARAMETER SYMBOL TEST CONDITIONS MIN. TYP. MAX. UNIT

Quiescent Current IDD - 260 370 µA Quiescent Current at OFF State IDD_OFF VEN = GND - - 0.1 µA Output Current Accuracy ILED -1.2 - +1.2 % Output (LED) Pin Leak Current 1 ILEAK1 VEN = GND, VDD = 35V, VLED = 35V - - 0.1 µA

Output (LED) Pin Leak Current 2 ILEAK2 VPWM = GND VDD = 35V, VLED = 35V - - 0.1 µA

EN Pin ON Voltage VEN_ON ILED = OFF ON 1.6 - VDD V EN Pin OFF Voltage VEN_OFF ILED = ON OFF 0 - 0.3 V PWM Pin ON Voltage 1 VPWM_ON 1 VDD < 5V, ILED = OFF ON 0.7VDD - VDD V PWM Pin OFF Voltage 1 VPWM_OFF 1 VDD < 5V, ILED = ON OFF 0 - 0.3VDD V PWM Pin ON Voltage 2 VPWM_ON 2 VDD 5V, ILED = OFF ON 3.5 - 5.5 V PWM Pin OFF Voltage 2 VPWM_OFF 2 VDD 5V, ILED = ON OFF 0 - 1.5 V EN Pin Input Current IEN VEN = 12V - 7 - µA PWM Pin Pull Up Resistance RPWM - 1 - MΩ RS Pin Output Current IOUT_RS LED = OPEN - 2.3 - µA PWM Pin ON Delay Time tPWM_ON VPWM = L H, ILED = OFF ON - 3 - µs PWM Pin OFF Delay Time tPWM_OFF VPWM = H L, ILED = ON OFF - 1 - µs LED Short Protection Detect Voltage VLED_SHORT 17 20 23 V

Maximum Output Current ILED_MAX RS = 0 Ω 100 170 - mA

NJW4615A

- 4 - Ver.2017-06-14

TYPICAL APPLICATIONS

Output Current Wave Format PWM Dimming

ControlLogic

Current Limit Thermal Shut Down

LED Short Protection

VREF( 0.2V )

GND EN PWM

RS

VDD

VDD / V+

H : ONL : OFF

LED

RS : Current Sense Resistor

ILED

ILED

0

(*3)

The Rs Resistance Setting formula: )()(.)(

AIVR

LEDS

20

(*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.

NJW4615A

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TYPICAL CHARACTERISTICS

0

50

100

150

200

250

300

350

400

0 10 20 30 40

Qui

esce

nt C

urre

nt: I

DD[μ

A]

Supply Voltage : VDD [V]

Quiescent Current vs. Supply Voltage[VEN=VDD, VLED=1V, RS=10Ω, VPWM=OPEN]

-40

25

125

1500

50

100

150

200

250

300

350

400

-50 -25 0 25 50 75 100 125 150

Qui

esce

nt C

urre

nt: I

DD

[μA]

Temperature : [ºC]

Quiescent Current vs. Temperature[VDD=12V, VEN=VDD, VLED=1V, RS=10Ω, VPWM=OPEN]

0.1

1

10

100

-50 -25 0 25 50 75 100 125 150Qui

esce

nt C

urre

ntat

OFF

Sta

te：

I DD

_OFF

[nA

]

Temperature : [ºC]

Quiescent Current at OFF State vs. Temperature[VEN=GND, VLED=1V, RS=10Ω, VPWM=OPEN]

VDD=2.5V

VDD=12V

VDD=35V

0.1

1

10

100

1000

-50 -25 0 25 50 75 100 125 150

Out

put P

in L

eak

Cur

rent

1 : I

LEA

K1

[nA]

Temperature [ºC]

Output Pin Leak Current 1 vs. Temperature[VDD=35V, VLED=35V, VEN=GND, RS=10Ω, VPWM=OPEN]

VLED=1V

VLED=5V

VLED=35V

0.1

1

10

100

1000

-50 -25 0 25 50 75 100 125 150

Out

put P

in L

eak

Cur

rent

2 :

I LEAK

2 [n

A]

Temperature : [ºC]

Output Pin Leak Current 2 vs. Temperature[VDD=35V, VEN=VDD, VLED=35V, RS=10Ω, VPWM=GND]

NJW4615A

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TYPICAL CHARACTERISTICS

0.5

1

1.5

0 10 20 30 40

EN P

in O

N V

olta

ge :

V EN

_ON

[V]

Supply Voltage : VDD [V]

EN Pin ON Voltage vs. Supply Voltage [VLED=1V, RS=10Ω, VPWM=OPEN]

-40

25

125

150

0

0.2

0.4

0.6

0.8

1

1.2

1.4

-50 -25 0 25 50 75 100 125 150

EN P

in O

N V

olta

ge :

V EN

_ON

[V]

Temperature : [ºC]

EN Pin ON Voltage vs. Temperature[VDD=12V, VLED=1V, RS=10Ω, VPWM=OPEN]

0.5

1

1.5

0 10 20 30 40

EN P

in O

FF V

olta

ge :

V EN

_OFF

[V]

Supply Voltage : VDD [V]

EN Pin OFF Voltage vs. Supply Voltage [VLED=1V, RS=10Ω, VPWM=OPEN]

-40

25

125

150

0

0.2

0.4

0.6

0.8

1

1.2

1.4

-50 -25 0 25 50 75 100 125 150

EN P

in O

FF V

olta

ge :

V EN

_OFF

[V]

Temperature : [ºC]

EN Pin OFF Voltage vs. Temperature[VDD=12V, VLED=1V, RS=10Ω, VPWM=OPEN]

0

0.5

1

1.5

2

2.5

3

0 10 20 30 40

PWM

Pin

ON

Vol

tage

: V P

WM

_ON

[V]

Supply Voltage : VDD [V]

PWM Pin ON Voltage vs. Supply Voltage [VEN=VDD, VLED=1V, RS=10Ω]

-40

25

125

150

0

0.5

1

1.5

2

2.5

3

-50 -25 0 25 50 75 100 125 150

PWM

Pin

ON

Vol

tage

: V P

WM

_ON

[V]

Temperature : [ºC]

PWM Pin ON Voltage vs. Temperature[VEN=VDD, VLED=1V, RS=10Ω]

VDD=12V

VDD=2.5V

NJW4615A

- 7 - Ver.2017-06-14

TYPICAL CHARACTERISTICS

0

0.5

1

1.5

2

2.5

3

0 10 20 30 40

PWM

Pin

OFF

Vol

tage

: V P

WM

_OFF

[V]

Supply Voltage : VDD [V]

PWM Pin OFF Voltage vs. Supply Voltage [VEN=VDD, VLED=1V, RS=10Ω]

-40

25

125

150

0

0.5

1

1.5

2

2.5

3

-50 -25 0 25 50 75 100 125 150

PWM

Pin

OFF

Vol

tage

: V P

WM

_OFF

[V]

Temperature : [ºC]

PWM Pin OFF Voltage vs. Temperature[VEN=VDD, VLED=1V, RS=10Ω]

VDD=12V

VDD=2.5V

0

10

20

30

40

50

60

0 10 20 30 40

EN P

in In

put C

urre

nt :

I EN[μ

A]

EN Pin Voltage : VEN [V]

EN Pin Input Current vs. EN Pin Voltage[VDD=12V, VLED=1V, RS=10Ω]

-40

25

125

150

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

-50 -25 0 25 50 75 100 125 150

PWM

Pin

Pul

l-up

Res

ista

nce

: RPW

M[MΩ]

Temperature : [ºC]

PWM Pin Pull-up Resistance vs. Temperature[VDD=12V, VLED=1V, RS=10Ω, VPWM=OPEN]

0

1

2

3

4

5

6

7

8

0 10 20 30 40

PWM

Pin

Inpu

t Cur

rent

: I P

WM

[μA]

Supply Voltage : VDD [V]

PWM Pin Input Current vs. Supply Voltage [VEN=VDD, VLED=1V, RS=10Ω, VPWM=GND]

-40

25

125

150

NJW4615A

- 8 - Ver.2017-06-14

TYPICAL CHARACTERISTICS

0

1

2

3

4

5

6

7

8

9

10

-50 -25 0 25 50 75 100 125 150

PWM

Pin

ON

Del

ay T

ime

: tPW

M_O

N[μ

s]

Temperature : [ºC]

PWM Pin ON Delay Time vs. Temperature[VDD=12V, VEN=VDD, VLED=1V]

Rs=40Ω

Rs=10Ω

Rs=2Ω

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

-50 -25 0 25 50 75 100 125 150

PWM

Pin

OFF

Del

ay T

ime

: tPW

M_O

FF[μ

s]Temperature : [ºC]

PWM Pin OFF Delay Time vs. Temperature[VDD=12V, VEN=VDD, VLED=1V]

RS=40Ω

RS=10Ω

RS=2Ω

19.5

20

20.5

0 10 20 30 40

Out

put C

urre

nt :

I LED

[mA]

Output Pin Voltage : VLED [V]

Output Current vs. Output Pin Voltage[VDD=12V, VEN=VDD, RS=10Ω]

0

20

40

60

80

100

120

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Out

put C

urre

nt: I

LED

[mA]

Output Pin Voltage : VLED [V]

Output Current vs. Output Pin Voltage[VDD=12V, VEN=VDD]

RS=40Ω

RS=10Ω

RS=2Ω

19.5

19.6

19.7

19.8

19.9

20

20.1

20.2

20.3

20.4

20.5

-50 -25 0 25 50 75 100 125 150 175 200

Out

put C

urre

nt :

I LED

[mA

]

Temperature : [ºC]

Output Current vs.Temperature[VDD=12V, VEN=VDD, VLED=1V, RS=10Ω]

NJW4615A

- 9 - Ver.2017-06-14

TYPICAL CHARACTERISTICS

0

5

10

15

20

25

-50 -25 0 25 50 75 100 125 150

LED

Shor

t Pro

tect

ion

Volta

ge:

V LED

_SH

OR

T/O

FF[V

]

Temperature [ºC]

LED Short Protection Voltage vs. Temperatue[VDD=12V, VEN=VDD, RS=0Ω]

Detect Voltage

Release Voltage

0

20

40

60

80

100

120

140

160

0 10 20 30 40

Max

imu

Out

put C

urre

nt: I

LED

_MAX

[mA]

Output Pin Voltage: VLED [V]

Maximum Output Current vs. Output Pin Voltage[VDD=12V, VEN=VDD, RS=0Ω]

Release Voltage

Detect Voltage

0

20

40

60

80

100

120

140

160

180

200

-50 -25 0 25 50 75 100 125 150

Max

imum

Out

put C

urre

nt :

I LED

_MAX

[mA]

Temperature : [ºC]

Maximum Output Current vs. Temperature[VDD=12V, VEN=VDD, RS=0Ω]

VLED=1V

VLED=35V

1

10

100

1 10 100

Out

put C

urre

nt: I

LED

[mA]

Current Sense Resistance : RS [Ω]

Output Current vs. Current Sense Resistance[VDD=12V, VEN=VDD, VLED=1V]

NJW4615A

- 10 - Ver.2017-06-14

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 NJW4615A, it is necessary as minimum V+ that is ΣLED Vf + NJW4615A output voltage (VLED = 1V). The maximum LED connected number that NJW4615A can drive is limited by the recommended output voltage maximum value (35V). Moreover, it should be used with ΣLED Vf within 34V 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 11 lights

LED Vf is up to 3.2V up to 10 lights

LED Vf is up to 3.7V up to 9 lights

LED Vf is up to 4.2V up to 8 lights

VDD

LED

RS

ControlLogic

Current Limit Thermal Shut Down

LED Short Protection

+VREF

(0.2V)

PWMENGND

V+ 35VVDD

Vf n pcs. = LEDVf 34V

(*4) (*3)

(*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.

NJW4615A

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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

Output Current PWM ON/OFF Propagation Delay( Output Current Pulse Width Error : εt = tPWM_ON - tPWM_OFF)

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. 2µs (Output Current: ILED=20mA,Ta=25 C typ. <Reference Value> )

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 = -2 [µs] / 50 [µs] × 100 = -4 [%]

【 Measurement Conditions 】 Output Current (ILED) 5mA (RS = 40Ω) 20mA (RS = 10Ω) 100mA (RS = 2Ω) 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. Ambient Temperature Ta=25ºC

0.01

0.1

1

10

100

0.01 0.1 1 10 100

Out

put C

urre

nt D

uty

[%]

PWM Input Pulse Duty [%]

Output Current Duty vs. PWM Input Pulse Duty

ILED=5mA

ILED=20mA

ILED=100mA

NJW4615A

- 12 - Ver.2017-06-14

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. 170mA (output (LED) pin voltage=1V, Ta=25 C). 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. 60mA when the output (LED) pin voltage rose to approx. 20V.

Thermal Shutdown Function (Refer to Output Current vs. Temperature) When junction temperature of the NJW4615A exceeds the 170°C*, internal thermal shutdown circuit function stops

the device function. When junction temperature decreases to 150°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

NJW4615A

- 13 - Ver.2017-06-14

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. PD ≈ VDD IDD + (VLED - VRS) ILED

= VDD IDD + (V+ - LED Vf - 0.2) ILED [W] Rs pin voltage (VRS): 0.2V ΣLED Vf represents the sum of the LED Vf of use. e.g.) VDD = V+ = 12[V], IDD=260[µA], LED Vf = 9[V], ILED = 100[mA] PD ≈ 12[V] 260[µA] + (12[V] - 9[V] -0.2[V]) 100[mA] ≈ 283[mW] 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.

It should set the LED operating Voltage (V+) and output current (ILED) with consideration of PD.

The device power dissipation must be below the power dissipation rate of the device package including thermal derating to ensure correct operation.

(*1) Mounted on glass epoxy board based on EIA/JEDEC. (76.2×114.3×1.6mm: 2Layers FR-4) (*2) Mounted on glass epoxy board based on EIA/JEDEC. (76.2×114.3×1.6mm: 4Layers FR-4), Internal Cu area: 74.2×74.2mm

0

100

200

300

400

500

600

700

800

-50 -25 0 25 50 75 100 125 150

Pack

age

Pow

er :

Pd [m

W]

Ambient Temperature : Ta [ºC]

NJW4615AF1 (SOT-23-6)Power Dissipation

(Topr=-40ºC to +125ºC, Tj=150ºC)

(*2) on 4 Layers Board

(*1) on 2 Layers Board

VDD

LED

RS

ControlLogic

Current Limit Thermal Shut Down

LED Short Protection

+VREF

(0.2V)

PWMENGND

VDD

LEDVf

V+

ILED

VLED - VRS

IDD

(*4) (*3)

NJW4615A

- 14 - Ver.2017-06-14

Application Manual Parallel Drive of NJW4615A For applications that require more than 100mA, it can correspond by parallel connecting two or more NJW4615A. The LED current becomes sum of LED current of each NJW4615A.

Each device accepts different set current. ILED [A] = ILED1 + ILED2 = 0.2 / RS1 [Ω] + 0.2 / RS2 [Ω] (e.g. ILED = 150 [mA] setting: RS1 = 4[Ω], RS2 = 2 [Ω] ）

VDD

LED

RS

ControlLogic

Current Limit Thermal Shut Down

LED Short Protection

+VREF

(0.2V)

PWMENGND

VDD

LED

RS

ControlLogic

Current Limit Thermal Shut Down

LED Short Protection

+VREF

(0.2V)

PWMEN

RS1 RS2

GND

PWM

VDD

V+

ILED

ILED1 ILED2(*4)

(*3)

NJW4615A

- 15 - Ver.2017-06-14

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.