Texas Instruments Incorporated AN-2082 User's Guide
AN-2082 LM3444 -120VAC, 8W Isolated Flyback LED
1 Introduction
This demonstration board highlights the performance of a LM3444 based Flyback LED driver solution that
can be used to power a single LED string consisting of 4 to 8 series connected LEDs from an 90 V
135 V
conditions are summarized in this application note.
This is a two-layer board using the bottom and top layer for component placement. The demonstration
board can be modified to adjust the LED forward current, the number of series connected LEDs that are
driven and the switching frequency. Refer to the LM3444 AC-DC Offline LED Driver (SNVS682) data
sheet for detailed instructions.
A bill of materials is included that describes the parts used on this demonstration board. A schematic and
layout have also been included along with measured performance characteristics.
, 60 Hz input power supply. The key performance characteristics under typical operating
RMS
User's Guide
SNVA454E–September 2010–Revised May 2013
Driver
to
RMS
2 Key Features
• Line injection circuitry enables PFC values greater than 0.99
• Adjustable LED current and switching frequency
• Flicker free operation
3 Applications
• Solid State Lighting
• Industrial and Commercial Lighting
• Residential Lighting
4 Performance Specifications
Based on an LED Vf= 3.57V
Symbol Parameter Min Typ Max
V
IN
V
OUT
I
LED
P
OUT
f
sw
Input voltage 90 V
LED string voltage 12 V 21.4 V 30 V
LED string average current - 350 mA -
Output power - 7.6 W -
Switching frequency - 79 kHz -
RMS
120 V
RMS
135 V
RMS
PowerWise is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
SNVA454E–September 2010–Revised May 2013 AN-2082 LM3444 -120VAC, 8W Isolated Flyback LED Driver
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1
Performance Specifications
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Figure 1. Demo Board
2
AN-2082 LM3444 -120VAC, 8W Isolated Flyback LED Driver SNVA454E–September 2010–Revised May 2013
Copyright © 2010–2013, Texas Instruments Incorporated
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R15
C11
FILTER
R2
R7
R1
R3
D7
Q1
NC
NC
NC
COFF
FILTER
NC
VCC
GND
GATE
ISNS
LM3444
1
2
3
4
5
10
9
8
7
6
V+
C7 C8
V
CC
R22 D8
R12
R13 R14
+
VLED+
VLED±
L1
V+
LINE
NEUTRAL
INPUT EMI FILTER AND RECTIFIER CIRCUIT
Q2
D1
D3
D4
D5C3
C4
R16
C12
C1
C6
L2
R6
R24
C2
RT1
D2
F1
T1
C13
+
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LM3444 120VAC, 8W Isolated Flyback LED Driver Demo Board Schematic
5 LM3444 120VAC, 8W Isolated Flyback LED Driver Demo Board Schematic
WARNING
The LM3444 evaluation board has exposed high voltage
SNVA454E–September 2010–Revised May 2013 AN-2082 LM3444 -120VAC, 8W Isolated Flyback LED Driver
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components that present a shock hazard. Caution must be taken
when handling the evaluation board. Avoid touching the evaluation
board and removing any cables while the evaluation board is
operating. Isolating the evaluation board rather than the
oscilloscope is highly recommended.
Copyright © 2010–2013, Texas Instruments Incorporated
3
1
4
3
2
10
7
8
9
I
SNS
NC
GATE
NC
COFF
V
CC
NC
NC
5 6FILTER GND
LM3444 Device Pin-Out
The ground connection on the evaluation board is NOT referenced
to earth ground. If an oscilloscope ground lead is connected to the
evaluation board ground test point for analysis and AC power is
applied, the fuse (F1) will fail open. The oscilloscope should be
powered via an isolation transformer before an oscilloscope
ground lead is connected to the evaluation board.
The LM3444 evaluation board should not be powered with an open
load. For proper operation, ensure that the desired number of LEDs
are connected at the output before applying power to the
evaluation board.
6 LM3444 Device Pin-Out
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WARNING
WARNING
Pin # Name Description
10 NC No internal connection.
4
AN-2082 LM3444 -120VAC, 8W Isolated Flyback LED Driver SNVA454E–September 2010–Revised May 2013
Table 1. Pin Description 10-Pin VSSOP
1 NC No internal connection.
2 NC No internal connection.
3 NC No internal connection.
4 COFF OFF time setting pin. A user set current and capacitor connected from the output to this pin sets the constant
5 FILTER Filter input. A capacitor tied to this pin filters the error amplifier. Could also be used as an analog dimming
6 GND Circuit ground connection.
7 ISNS LED current sense pin. Connect a resistor from main switching MOSFET source, ISNS to GND to set the
8 GATE Power MOSFET driver pin. This output provides the gate drive for the power switching MOSFET of the buck
9 V
OFF time of the switching controller.
input.
maximum LED current.
controller.
Input voltage pin. This pin provides the power for the internal control circuitry and gate driver.
CC
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7 Bill of Materials
Designator Description Manufacturer Part Number
AA1 Printed Circuit Board - 551600530-001A
C1 CAP .047UF 630V METAL POLYPRO EPCOS Inc B32559C6473K000
C2 CAP 10000PF X7R 250VAC X2 2220 Murata Electronics North America GA355DR7GB103KY02L
C3, C4 CAP 330UF 35V ELECT PW Nichicon UPW1V331MPD6
C6 CAP .10UF 305VAC EMI SUPPRESSION EPCOS B32921C3104M
C7 CAP, CERM, 0.1µF, 16V, +/-10%, X7R, Kemet C0805C104K4RACTU
C8 CAP CER 47UF 16V X5R 1210 MuRata GRM32ER61C476ME15L
C11 CAP CER 2200PF 50V 10% X7R 0603 MuRata GRM188R71H222KA01D
C12 CAP CER 330PF 50V 5% C0G 0603 MuRata GRM1885C1H331JA01D
C13 CAP CER 2200PF 250VAC X1Y1 RAD TDK Corporation CD12-E2GA222MYNS
D1 DIODE TVS 150V 600W UNI 5% SMB Littlefuse SMAJ120A
D2 RECT BRIDGE GP 600V 0.5A MINIDIP Diodes Inc. RH06-T
D3 DIODE RECT GP 1A 1000V MINI-SMA Comchip Technology CGRM4007-G
D4 DIODE SCHOTTKY 100V 1A SMA ST Microelectronics STPS1H100A
D5 DIODE ZENER 30V 1.5W SMA ON Semiconductor 1SMA5936BT3G
D7 DIODE ZENER 12V 200MW Fairchild Semiconductor MM5Z12V
D8 DIODE SWITCH 200V 200MW Diode Inc BAV20WS-7-F
F1 FUSE BRICK 1A 125V FAST 6125FA Cooper/Bussmann 6125FA
J1, J2, J3, J4, 16 GA WIRE HOLE, 18 GA WIRE HOLE 3M 923345-02-C
TP8, TP9, TP10
J5, J6 CONN HEADER .312 VERT 2POS TIN Tyco Electronics 1-1318301-2
L1, L2 INDUCTOR 4700UH .13A RADIAL TDK Corporation TSL0808RA-472JR13-PF
Q1 MOSFET N-CH 600V 90MA SOT-89 Infineon Technologies BSS225 L6327
Q2 MOSFET N-CH 600V 1.8A TO-251 Infineon Technology SPU02N60S5
R1, R3 RES 200K OHM 1/4W 5% 1206 SMD Vishay-Dale CRCW1206200KJNEA
R2, R7 RES, 309k ohm, 1%, 0.25W, 1206 Vishay-Dale CRCW1206309KFKEA
R6, R24 RES, 10.5k ohm, 1%, 0.125W, 0805 Vishay-Dale CRCW080510K5FKEA
R12 RES 4.7 OHM 1/10W 5% 0603 SMD Vishay-Dale CRCW06034R70JNEA
R13 RES 10 OHM 1/8W 5% 0805 SMD Vishay-Dale CRCW080510R0JNEA
R14 RES 1.50 OHM 1/4W 1% 1206 SMD Vishay-Dale CRCW12061R50FNEA
R15 RES 3.48K OHM 1/10W 1% 0603 SMD Vishay-Dale CRCW06033K48FKEA
R16 RES 191K OHM 1/10W 1% 0603 SMD Vishay-Dale CRCW0603191KFKEA
R22 RES 40.2 OHM 1/8W 1% 0805 SMD Vishay-Dale CRCW080540R2FKEA
RT1 CURRENT LIMITOR INRUSH 60OHM Cantherm MF72-060D5
T1 Transformer Wurth Electronics 750311553 Rev. 01
TP2-TP5 Terminal, Turret, TH, Double Keystone Electronics 1502-2
TP7 TEST POINT ICT - -
U1 Offline LED Driver, PowerWise™ Texas Instruments LM3444
Bill of Materials
0805
20%
SNVA454E–September 2010–Revised May 2013 AN-2082 LM3444 -120VAC, 8W Isolated Flyback LED Driver
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5
LED +
LED -
NEUTRAL
LINE
J5
J6
TP3
TP2
TP4
TP5
Demo Board Wiring Overview
8 Demo Board Wiring Overview
Figure 2. Wiring Connection Diagram
Test Name I/O Description
Point
TP3 LED + Output LED Constant Current Supply
TP2 LED - Output LED Return Connection (not GND)
TP5 LINE Input AC Line Voltage
TP4 NEUTRAL Input AC Neutral
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Supplies voltage and constant-current to anode of LED string.
Connects to cathode of LED string. Do NOT connect to GND.
Connects directly to AC line of a 120VAC system.
Connects directly to AC neutral of a 120VAC system.
6
AN-2082 LM3444 -120VAC, 8W Isolated Flyback LED Driver SNVA454E–September 2010–Revised May 2013
Copyright © 2010–2013, Texas Instruments Incorporated
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