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Application Report
SNVA465A–March 2011–Revised April 2013
AN-2102 LM3464 and LM5021 DHC 25W Reference
Designs
.....................................................................................................................................................
ABSTRACT
This evaluation board consists of a Texas Instruments LM5021-based 120Vac 24W AC/DC flyback
converter and a LM3464-based dynamic head room control (DHC) four channel LED driver IC. This
demonstration platform was developed so that the customers could evaluate the LM3464 with an AC/DC
supply.
Contents
1 Introduction .................................................................................................................. 2
2 Key Features ................................................................................................................ 2
3 Performance Specifications ................................................................................................ 2
4 LM3464 120VAC, 24W Isolated 4 LED Driver Demo Board Schematic ............................................. 4
5 Bill of Materials (BOM) ..................................................................................................... 5
6 Typical Performance Characteristics ..................................................................................... 7
7 PCB Layout .................................................................................................................. 9
8 Design Information ........................................................................................................ 10
8.1 1
ST
Stage - DCM Flyback ........................................................................................ 10
8.2 2
ND
Stage - Dynamic Headroom Control ....................................................................... 10
8.3 Jumper/Fault Information ........................................................................................ 10
9 Electromagnetic Interference (EMI) ..................................................................................... 10
10 Thermal Analysis .......................................................................................................... 11
11 References ................................................................................................................. 12
List of Figures
1 Demo Board ................................................................................................................. 3
2 Efficiency vs. Line Voltage................................................................................................. 7
3 Power Factor vs. Line Voltage ............................................................................................ 7
4 Total LED Current vs. LED Temperature................................................................................ 7
5 Output Voltage & LED Forward Voltage vs. LED Temperature....................................................... 7
6 Ch1: Line Voltage (100 V/div); Ch3: Line Current (200 mA/div); Time (10 ms/div) ............................... 7
7 Ch1: Output Voltage (10 V/div); Ch3: Total LED Current (500 mA/div); Time (10 ms/div)........................ 7
8 Ch1: Drain Voltage (100V/div) Time (4 µs/div).......................................................................... 8
9 Ch1: Output Voltage (10 V/div); Ch3: Total LED Current (500 mV/div); Time (100 ms/div) ...................... 8
10 Top Layer .................................................................................................................... 9
11 Bottom Layer ................................................................................................................ 9
12 Peak Conductive EMI scan per CISPR-22, Class B Limits.......................................................... 11
13 Top Side Thermal Scan .................................................................................................. 11
List of Tables
1 Bill of Materials (BOM) ..................................................................................................... 5
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SNVA465A–March 2011–Revised April 2013 AN-2102 LM3464 and LM5021 DHC 25W Reference Designs
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