Driving High Power LEDs Starting from
700mA with Low Cost LED Controller IC
ILD4001
Application Note 213
http://www.infineon.com/lowcostleddriver
Rev. 1.1, 2011 -06 -23
Power Management & Multimarket
Edition 2011-07-01
Published by
Infineon Technologies AG
81726 Munich, Germany
© 2011 Infineon Technologies
AG All Rights Reserved.
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THE INFORMATION GIVEN IN THIS APPLICATION NOTE IS GIVEN AS A HINT FOR THE
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REGARDED AS ANY DESCRIPTION OR WARRANTY OF A CERTAIN FUNCTIONALITY, CONDITION OR
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NOTE MUST VERIFY ANY FUNCTION DESCRIBED HEREIN IN THE REAL APPLICATION. INFINEON
TECHNOLOGIES HEREBY DISCLAIMS ANY AND ALL WARRANTIES AND LIABILITIES OF ANY KIND
(INCLUDING WITHOUT LIMITATION WARRANTIES OF NON-INFRINGEMENT OF INTELLECTUAL
PROPERTY RIGHTS OF ANY THIRD PARTY) WITH RESPECT TO ANY AND ALL INFORMATION GIVEN IN
THIS APPLICATION NOTE.
Information
For further information on technology, delivery terms and conditions and prices, please contact the
nearest Infineon Technologies Office (www.infineon.com).
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Application Note AN213
Driving High Power LEDs Starting from 700mA with Low Cost LED Controller IC ILD4001
Application Note AN213
Revision History: 23 June 2011
Previous Revision: Previous_Revision_Number
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Application Note AN213, 1.1
3 / 20
23 June 2011
Application Note AN213
Driving High Power LEDs Starting from 700mA with Low Cost LED Controller IC ILD4001
Table of Contents
1
2
3
4
5
Introduction
.....................................................................................................................................................
5
Application Information
...............................................................................................................................
8
Characteristic Graphs for different Inductors, no. of LEDs, Rs
......................................................
13
Evaluation Board and layout Information
.............................................................................................
16
Equations for estimating switching frequency or Inductance
........................................................
19
List of Figures
Figure 1 ILD4001 ................................................................................................................................................ 5
Figure 2
Schematic of the demonstration board ................................................................................................ 8
Figure 3
Measurement setup for measuring Vsense voltage w.r.t. Vs pin ........................................................ 9
Figure 4
Vsw, Vsense and VLED(-), Vs=12 ...................................................................................................... 9
Figure 5
Switching Freq. vs Input Voltage,Vs .................................................................................................... 9
Figure 6
Dimming waveforms ......................................................................................................................... 10
Figure 7
Maximum Contrast Ratio vs Dimming frequency (100:1=1% Duty) ................................................. 10
Figure 8
Analog Dimming Characteristic ........................................................................................................ 10
Figure 9
EN pin current versus voltage .......................................................................................................... 12
Figure 10 ILED vs Vs (Rs = 0.158, L = 68 H) ................................................................................................. 13
Figure 11 ILED vs Vs (Rs = 0.075, L = 33 H) ................................................................................................. 13
Figure 12 Freq vs Vs (Rs = 0.158, L = 68 H) .................................................................................................. 13
Figure 13 Freq vs Vs (Rs = 0.075, L = 33 H) .................................................................................................. 13
Figure 14 Efficiency vs Vs (Rs = 0.158, L = 68 H) .......................................................................................... 14
Figure 15 Efficiency vs Vs (Rs = 0.075, L = 33 H) .......................................................................................... 14
Figure 16 ILED vs Ambient Temperature ........................................................................................................ 15
Figure 17 Efficiency vs Ambient Temperature................................................................................................... 15
Figure 18 Solder Point Temperature vs Ambient Temperature........................................................................ 15
Figure 19 Photograph of Demo Board using BSP381S external MOSFET (size of PCB: 50mm x 30mm) ..... 16
Figure 20 PCB Layer Information Top View ..................................................................................................... 16
Figure 21 PCB Layer information Bottom View (unflip) .................................................................................... 16
Figure 22 Thermal Resistance of PCB-FR4 versus Ground Copper Area ....................................................... 17
Figure 23 Thermal Resistance ......................................................................................................................... 18
List of Tables
Table 1
Table 2
Table 3
Table 4
Table 5
Demo Board for ILD4001
...............................................................................................................................
6
Comparison of BSP318S, BSR302N and BSS306N
.................................................................................
6
Bill-of-Materials
................................................................................................................................................
8
Percentage of max LED current vs DC voltage at PWM pin
..................................................................
11
Steps to calculate the switching frequency for the demo board
.............................................................
19
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23 June 2011
Application Note AN213
Driving High Power LEDs Starting from 700mA with Low Cost LED Controller IC ILD4001
1
1.1
Introduction
Features
Wide Input Voltage Range: 4.5 V ... 42 V
Capable to drive N-channel MOSFETs that
provide up to 3A output
Temperature shut down mechanism
Switching frequency up to 500 kHz
Analog and PWM dimming possible
Typical 3% output current accuracy
Very low LED current drift over temperature
Minimum external component required
Small Package: SC-74
Figure 1
ILD4001
1.2
Applications
LED controller for indoor and outdoor illumination
LED replacement lamps, e.g. MR16 halogen replacement
Retail, office and residential high power luminaires
Architectural lighting
Downlights and light engines
Appliances, e.g. fridge / freezer
1.3
Description
This document contains informations about the LED-Less Demonstration Board for ILD4001. Please refer to the
datasheet for the pins descriptions, functions descriptions and specifications.
The ILD4001 is a hysteretic buck LED controller IC for industrial applications.
The LED Controller is capable to drive external bipolar or MOSFET power transistors by using the internal push-
pull output stage.
ILD4001 maintains a constant current through a string of LEDs as long as the input voltage exceeds the sum of
the forward voltages of the LEDs in the string by at least 3V. The maximum input voltage for this demonstration
board must not exceed 30V due to the board is optimizing for the 30V operation. If there is a need to test the
board with a maximum supply voltage of 42V, please replace the schottky diode SD1 and the external MOSFET
T1 with a suitable breakdown voltage.
The precise internal bandgap stabilizes the circuit and provides stable current conditions over temperature
range.
Furthermore, temperature shut down mechanism enforce the IC to protect attached LEDs.
The board includes an
“EN/PWM” input terminal for
digital or analog dimming control signal.
The demonstration board is designed to operate at ambient temperatures up to 100C.
The complete demonstration board schematic is shown in
curves are shown in Figure 4 to Figure 8.
Figure 2. Typical waveforms and performance
Although a wide variety of LED combinations and currents can be driven with the ILD4001, the sense-resistors
have to be altered to achieve the desire LED current and inductance has to be changed to attain recommended
switching frequencies below 500 kHz.
Application Note AN213, 1.1
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23 June 2011