NUD4011 D

NUD4011
Low Current LED Driver
This device is designed to replace discrete solutions for driving
LEDs in AC/DC high voltage applications (up to 200 V). An external
resistor allows the circuit designer to set the drive current for different
LED arrays. This discrete integration technology eliminates individual
components by combining them into a single package, which results in
a significant reduction of both system cost and board space. The
device is a small surface mount package (SO−8).
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PIN CONFIGURATION
AND SCHEMATIC
Features
•
•
•
•
Supplies Constant LED Current for Varying Input Voltages
External Resistor Allows Designer to Set Current – up to 70 mA
Offered in Surface Mount Package Technology (SO−8)
Pb−Free Package is Available
Vin
1
8
Iout
Boost
2
7
Iout
Rext
3
6
Iout
PWM
4
5
Iout
Benefits
•
•
•
•
Maintains a Constant Light Output During Battery Drain
One Device can be used for Many Different LED Products
Reduces Board Space and Component Count
Simplifies Circuit and System Designs
Current
Set Point
Typical Applications
• Portables: For Battery Back−up Applications, also Simple Ni−CAD
•
•
Battery Charging
Industrial: General Lighting Applications and Small Appliances
Automotive: Tail Lights, Directional Lights, Back−up Light,
Dome Light
PIN FUNCTION DESCRIPTION
Pin
Symbol
1
Vin
2
Boost
This pin may be used to drive an external transistor
as described in the App Note AND8198/D.
3
Rext
An external resistor between Rext and Vin pins sets
different current levels for different application needs
4
PWM
For high voltage applications (higher than 48 V),
pin 4 is connected to the LEDs array.
For low voltage applications (lower than 48 V), pin 4
is connected to ground.
5, 6, 7, 8
Iout
Description
Positive input voltage to the device
The LEDs are connected from these pins to ground
MARKING
DIAGRAM
8
SO−8
CASE 751
8
1
1
4011
AYWWG
G
A
= Assembly Location
Y
= Year
WW
= Work Week
G
= Pb−Free Package
(Note: Microdot may be in either location)
ORDERING INFORMATION
Device
NUD4011DR2
NUD4011DR2G
Package
Shipping †
SO−8
2500 / Tape & Reel
SO−8
2500 / Tape & Reel
(Pb−Free)
†For information on tape and reel specifications,
including part orientation and tape sizes, please
refer to our Tape and Reel Packaging Specification
Brochure, BRD8011/D.
© Semiconductor Components Industries, LLC, 2006
June, 2006 − Rev. 3
1
Publication Order Number:
NUD4011/D
NUD4011
MAXIMUM RATINGS (TA = 25°C unless otherwise noted)
Rating
Symbol
Value
Unit
Input Voltage
Vin
200
V
Output Current
(For Vdrop ≤ 16 V) (Note 1)
Iout
70
mA
Output Voltage
Vout
198
V
Human Body Model (HBM)
ESD
500
V
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.
1. Vdrop = Vin – 0.7 V − VLEDs.
THERMAL CHARACTERISTICS
Characteristic
Symbol
Value
Unit
Operating Ambient Temperature
TA
−40 to +125
°C
Maximum Junction Temperature
TJ
150
°C
TSTG
−55 to +150
°C
PD
1.13
9.0
W
mW/°C
Thermal Resistance, Junction–to–Ambient (Note 2)
RJA
110
°C/W
Thermal Resistance, Junction–to–Lead (Note 2)
RJL
77
°C/W
Storage Temperature
Total Power Dissipation (Note 2)
Derating above 25°C (Figure 3)
2. Mounted on FR−4 board, 2 in sq pad, 1 oz coverage.
ELECTRICAL CHARACTERISTICS (TA = 25°C unless otherwise noted)
Symbol
Min
Typ
Max
Unit
Output Current1 (Note 3)
(Vin = 120 Vdc, Rext = 24 , VLEDs = 90 V)
Characteristic
Iout1
26.0
27.5
29.5
mA
Output Current2 (Note 3)
(Vin = 200 Vdc, Rext = 68 , VLEDs = 120 V)
Iout2
11.5
14.0
15.5
mA
Bias Current
(Vin = 120 Vdc, Rext = Open, Rshunt = 80 k)
IBias
−
1.1
2.0
mA
Voltage Overhead (Note 4)
Vover
5.0
−
−
V
3. Device’s pin 4 connected to the LEDs array (as shown in Figure 5).
4. Vover = Vin – VLEDs.
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2
NUD4011
TYPICAL PERFORMANCE CURVES
(TA = 25°C unless otherwise noted)
1000
0.9
0.8
0.7
100
Rext, Vsense (V)
0.6
10
0.5
0.4
0.3
0.2
0.1
1
1
10
100
0.0
−40 −25 −10 5 20 35 50 65 80 95 110 125 140 155
TJ, JUNCTION TEMPERATURE (°C)
1000
IOUT (mA)
Figure 1. Output Current (IOUT)
vs. External Resistor (Rext)
Figure 2. Vsense vs. Junction Temperature
1.2
PD, POWER DISSIPATION (W)
OUTPUT CURRENT, NORMALIZED
1.200
1.000
0.800
0.600
0.400
0.200
0.000
25
35
45
55
65
75
85
95
105 115 125
1.0
0.8
0.6
0.4
0.2
0.0
−40 −25 −10 5
20 35 50 65 80 95 110 125 140 155
TJ, JUNCTION TEMPERATURE (°C)
TA, AMBIENT TEMPERATURE (°C)
Figure 3. Total Power Dissipation (PD)
vs. Ambient Temperature (TA)
Figure 4. Current Regulation vs. Junction
Temperature
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3
NUD4011
APPLICATION INFORMATION
Design Guide for DC Applications
NUD4011
Vin
1. Define LED’s current:
a. ILED = 30 mA
Boost
2. Calculate Resistor Value for Rext:
a. Rext = Vsense (see Figure 2) / ILED
b. Rext = 0.7(TJ = 25 °C) / 0.030 = 24 Rext
PWM
3. Define Vin:
a. Per example in Figure 5, Vin = 120 Vdc
4. Define VLED @ ILED per LED supplier’s data
sheet: per example in Figure 5,
a. VLED = 3.0 V (30 LEDs in series)
b. VLEDs = 90 V
1
8
2
7
3
4
Current
Set Point
6
5
120 V
Iout
Iout
Iout
Iout
LED1
LED2
5. Calculate Vdrop across the NUD4001 device:
a. Vdrop = Vin – Vsense – VLEDs
b. Vdrop = 120 V – 0.7 V – 90 V
c. Vdrop = 29.3 V
LED30
6. Calculate Power Dissipation on the NUD4001
device’s driver:
a. PD_driver = Vdrop * Iout
b. PD_driver = 29.3 V
0.030 A
c. PD_driver = 0.879 W
Figure 5. 120 V Application
(Series LED’s Array)
7. Establish Power Dissipation on the NUD4001
device’s control circuit per below formula:
a. PD_control = (Vin – 1.4 – VLEDs)@ / 20,000
b. PD_control = 0.040 W
8. Calculate Total Power Dissipation on the device:
a. PD_total = PD_driver + PD_control
b. PD_total = 0.879 W + 0.040 W = 0.919 W
9. If PD_total > 1.13 W (or derated value per
Figure 3), then select the most appropriate
recourse and repeat steps 1−8:
a. Reduce Vin
b. Reconfigure LED array to reduce Vdrop
c. Reduce Iout by increasing Rext
d. Use external resistors or parallel device’s
configuration
10. Calculate the junction temperature using the
thermal information on Page 8 and refer to
Figure 4 to check the output current drop due to
the calculated junction temperature. If desired,
compensate it by adjusting the value of Rext.
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4
NUD4011
APPLICATION INFORMATION (continued)
Design Guide for AC Applications
Vin
Full
Bridge
Rectifier 1
1. Define LED’s current:
a. ILED = 30 mA
2. Define Vin:
a. Per example in Figure 5, Vin = 120 Vac
2
3
1
Iout
8
Boost
Iout
2
Rext
3. Define VLED @ ILED per LED supplier’s data
sheet:
a. Per example in Figure 6,
VLED = 3.0 V (30 LEDs in series)
VLEDs = 90 V
4
+
−
120 Vac
60 Hz
NUD4011
3
7
Current
Set Point
PWM
4
Iout
6
Iout
5
LED1
4. Calculate Resistor Value for Rext:
The calculation of the Rext for AC applications is
totally different than for DC. This is because
current conduction only occurs during the time
that the ac cycles’ amplitude is higher than VLEDs.
Therefore Rext calculation is now dependent on the
peak current value and the conduction time.
a. Calculate for VLEDs = 90 V:
Sin V = Vpeak
Ǹ2)
90 V = (120
Sin LED2
LED30
Figure 6. 120 Vac Application
(Series LED’s array)
= 32.027°
b. Calculate conduction time for = 32.027°. For
a sinuousoidal waveform Vpeak happens at
= 90°. This translates to 4.165 ms in time for
a 60 Hz frequency, therefore 32.027° is 1.48 ms
and finally:
Conduction time = (4.165 ms – 1.48 ms)
2
= 5.37 ms
c. Calculate the Ipeak needed for I(avg) = 30 mA
Since a full bridge rectifier is being used (per
Figure 6), the frequency of the voltage signal
applied to the NUD4011 device is now 120 Hz.
To simplify the calculation, it is assumed that
the 120 Hz waveform is square shaped so that
the following formula can be used:
I(avg) = Ipeak
duty cycle;
If 8.33 ms is 100% duty cycle, then 5.37 ms is
64.46%, then:
Ipeak = I(avg) / duty cycle
Ipeak = 30 mA / 0.645 = 46 mA
d. Calculate Rext
Rext = 0.7 V / Ipeak
Rext = 15.21 6. Calculate Power Dissipation on the NUD4011
device’s driver:
a. PD_driver = Vdrop * I(avg)
b. PD_driver = 29.3 V
0.030 A
c. PD_driver = 0.879 W
7. Establish Power Dissipation on the
NUD4011device’s control circuit per below
formula:
a. PD_control = (Vin – 1.4 – VLEDs)@ / 20,000
b. PD_control = 0.040 W
8. Calculate Total Power Dissipation on the device:
a. PD_total = PD_driver + PD_control
b. PD_total = 0.879 W + 0.040 W = 0.919 W
9. If PD_total > 1.13 W (or derated value per
Figure 3), then select the most appropriate
recourse and repeat steps 1−8:
a. Reduce Vin
b. Reconfigure LED array to reduce Vdrop
c. Reduce Iout by increasing Rext
d. Use external resistors or parallel device’s
configuration
5. Calculate Vdrop across the NUD4011 device:
a. Vdrop = Vin – Vsense – VLEDs
b. Vdrop = 120 V – 0.7 V – 90 V
c. Vdrop = 29.3 V
10. Calculate the junction temperature using the
thermal information on Page 8 and refer to
Figure 4 to check the output current drop due to
the calculated junction temperature. If desired,
compensate it by adjusting the value of Rext.
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5
NUD4011
TYPICAL APPLICATION CIRCUITS
NUD4011
Switch
Vin
35 , 1/4 W
Boost
Rext
PWM
+
−
1
8
2
7
Current
Set Point
3
6
4
5
Iout
Iout
Iout
Iout
120 Vdc
LED1
LED2
LED30
Figure 7. 120 Vdc Application Circuit for a Series Array of 30 LEDs (3.0 V, 20 mA)
NUD4011
Vin
Full
Bridge
Rectifier
Switch
+
2
VARISTOR
200 V
−
1
30 , 1/4 W
3
Boost
Rext
PWM
4
1
8
2
7
3
4
Current
Set Point
6
5
Iout
Iout
Iout
Iout
120 Vac 60 Hz
LED1
LED2
LED30
Figure 8. 120 Vac Application Circuit for a Series Array of 30 LEDs (3.0 V, 20 mA)
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6
NUD4011
TYPICAL APPLICATION CIRCUITS (continued)
Switch
35 , 1/4 W
NUD4011
Vin
Boost
Rext
PWM
120 Vdc
8
2
7
Current
Set Point
3
6
4
+
−
1
5
Rshunt
80 k, 1/4 W
1.0 k
+
−
Iout
Iout
Iout
Iout
LED1
Q1
200 V
LED2
PWM /
ENABLE
LED30
Figure 9. 120 Vdc Application with PWM / Enable Function, 30 LEDs in Series (3.0 V, 20 mA)
NUD4011
Vin
Full
Bridge
Rectifier
Switch
+
2
VARISTOR
200 V
−
120 Vac 60 Hz
1
35 , 1/4 W
3
4
Boost
Rext
200 V
Electrolytic
Cap
PWM
1
8
2
7
3
4
Rshunt
80 k, 1/4 W
1.0 k
+
PWM /
ENABLE
−
Q1
200 V
Current
Set Point
6
5
Iout
Iout
Iout
Iout
LED1
LED2
LED30
Figure 10. 120 Vac Application with PWM / Enable Function, 30 LEDs in Series (3.0 V, 20 mA)
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7
NUD4011
THERMAL INFORMATION
NUD4011 Power Dissipation
reduce the thermal resistance. Figure 11 shows how the
thermal resistance changes for different copper areas.
Another alternative would be to use a ceramic substrate or
an aluminum core board such as Thermal Clad®. Using a
board material such as Thermal Clad or an aluminum core
board, the power dissipation can be even doubled using the
same footprint.
The power dissipation of the SO−8 is a function of the pad
size. This can vary from the minimum pad size for soldering
to a pad size given for maximum power dissipation. Power
dissipation for a surface mount device is determined by
TJ(max), the maximum rated junction temperature of the die,
RJA, the thermal resistance from the device junction to
ambient, and the operating temperature, TA. Using the
values provided on the data sheet for the SO−8 package, PD
can be calculated as follows:
180
160
T
* TA
PD + Jmax
RJA
140
JA (°C/W)
The values for the equation are found in the maximum
ratings table on the data sheet. Substituting these values into
the equation for an ambient temperature TA of 25°C, one can
calculate the power dissipation of the device which in this
case is 1.13 W.
120
100
80
PD + 150°C * 25°C + 1.13 W
110°C
60
The 110°C/W for the SO−8 package assumes the use of a
FR−4 copper board with an area of 2 square inches with 2 oz
coverage to achieve a power dissipation of 1.13 W. There are
other alternatives to achieving higher dissipation from the
SOIC package. One of them is to increase the copper area to
0
1
2
3
4
5
6
7
8
9
10
BOARD AREA (in2)
Figure 11. qJA versus Board Area
250
1S −36.9 sq. mm −0.057 in sq.
1S −75.8 sq. mm −0.117 in sq.
200
R() (C°/W)
1S −150.0 sq. mm −0.233 in sq.
150
1S −321.5 sq. mm −0.498 in sq.
1S −681.0 sq. mm −1.056 in sq.
100
1S −1255.0 sq. mm −1.945 in sq.
50
0
0.000001
0.00001
0.0001
0.001
0.1
0.01
1
TIME (sec)
Figure 12. Transient Thermal Response
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8
10
100
1000
NUD4011
PACKAGE DIMENSIONS
−X−
SOIC−8 NB
CASE 751−07
ISSUE AH
A
8
NOTES:
1. DIMENSIONING AND TOLERANCING PER
ANSI Y14.5M, 1982.
2. CONTROLLING DIMENSION: MILLIMETER.
3. DIMENSION A AND B DO NOT INCLUDE
MOLD PROTRUSION.
4. MAXIMUM MOLD PROTRUSION 0.15 (0.006)
PER SIDE.
5. DIMENSION D DOES NOT INCLUDE DAMBAR
PROTRUSION. ALLOWABLE DAMBAR
PROTRUSION SHALL BE 0.127 (0.005) TOTAL
IN EXCESS OF THE D DIMENSION AT
MAXIMUM MATERIAL CONDITION.
6. 751−01 THRU 751−06 ARE OBSOLETE. NEW
STANDARD IS 751−07.
5
S
B
1
0.25 (0.010)
M
Y
M
4
−Y−
K
G
C
N
DIM
A
B
C
D
G
H
J
K
M
N
S
X 45 _
SEATING
PLANE
−Z−
H
0.10 (0.004)
D
0.25 (0.010)
M
Z Y
S
X
M
J
S
MILLIMETERS
MIN
MAX
4.80
5.00
3.80
4.00
1.35
1.75
0.33
0.51
1.27 BSC
0.10
0.25
0.19
0.25
0.40
1.27
0_
8 _
0.25
0.50
5.80
6.20
INCHES
MIN
MAX
0.189
0.197
0.150
0.157
0.053
0.069
0.013
0.020
0.050 BSC
0.004
0.010
0.007
0.010
0.016
0.050
0 _
8 _
0.010
0.020
0.228
0.244
SOLDERING FOOTPRINT*
1.52
0.060
7.0
0.275
4.0
0.155
0.6
0.024
1.270
0.050
SCALE 6:1
mm Ǔ
ǒinches
*For additional information on our Pb−Free strategy and soldering
details, please download the ON Semiconductor Soldering and
Mounting Techniques Reference Manual, SOLDERRM/D.
Thermal Clad is a registered trademark of the Bergquist Company.
ON Semiconductor and
are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice
to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability
arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.
“Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All
operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights
nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications
intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should
Buyer purchase or use SCILLC products for any such unintended or unauthorized application, Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates,
and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death
associated with such unintended or unauthorized use, even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal
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NUD4011/D