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AN_1809_PL39_1810_124440
ILD8150 80 V high side buck LED driver IC with
hybrid dimming
Operation, design guide and performance
About this document
Scope and purpose
This application note introduces Infineon's hysteretic high-side MOSFET buck DC-DC LED driver IC ILD8150 for
general lighting applications. It describes the device operation, features and component value calculations and
selection. An example of the reference design performance is shown. ILD8150 provides a highly efficient
solution up to 97 percent with superior hybrid dimming performance, and various protections such as cycle-by-
cycle current limitation and over-temperature protection.
Intended audience
This document is intended for engineers and students who design highly efficient LED drivers with a wide
dimming range.
Table of contents
About this document ....................................................................................................................... 1
Table of contents ............................................................................................................................ 1
1
Introduction ............................................................................................................................. 3
1.1
Features .............................................................................................................................................................. 3
1.2
Applications ........................................................................................................................................................ 3
2
Circuit description ..................................................................................................................... 4
2.1
Operation ............................................................................................................................................................ 4
2.1.1
Current regulation ........................................................................................................................................... 4
2.2
Cycle-by-cycle current limitation ....................................................................................................................... 5
2.2.1
5
2.2.2
5
2.2.3
Dimming ........................................................................................................................................................... 6
2.2.4
Dim-to-off ......................................................................................................................................................... 7
2.2.5
Soft-start .......................................................................................................................................................... 7
2.2.6
Shut-down ....................................................................................................................................................... 8
2.2.7
Floating driver and bootstrap supplying ........................................................................................................ 8
2.2.8
V
pin ESD protection ...................................................................................................................................... 8
2.2.9
OVP by CS pin ................................................................................................................................................... 9
2.2.10
Microcontroller use........................................................................................................................................ 9
2.3
Component selection ....................................................................................................................................... 10
2.3.1
Current Sense (CS) resistor ........................................................................................................................... 10
2.3.2
Inductor and switching frequency selection ................................................................................................ 10
2.3.3
Diode D selection ........................................................................................................................................... 10
2.3.4
Application Note
www.infineon.com/ref-ild8150-dc-1.5a
Please read the Important Notice and Warnings at the end of this document
page 1 of 28
V 1.0
2019-01-18
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Summary of Contents for Infineon ILD8150
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Page 1: Table Of Contents
About this document Scope and purpose This application note introduces Infineon’s hysteretic high-side MOSFET buck DC-DC LED driver IC ILD8150 for general lighting applications. It describes the device operation, features and component value calculations and selection. An example of the reference design performance is shown. ILD8150 provides a highly efficient solution up to 97 percent with superior hybrid dimming performance, and various protections such as cycle-by- cycle current limitation and over-temperature protection. - Page 2 ILD8150 80 V high side buck LED driver IC with hybrid dimming Introduction 2.3.5 Output capacitor C selection ........................11 2.3.6 Bootstrap capacitor C selection ....................... 11 boot Layout consideration ............................11 Design example ..............................12 2.5.1 Determine R ..............................12 2.5.2...
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Page 3: Introduction
AC-DC such as Power Factor Correction (PFC) flyback or PFC + LLC. ILD8150 is flexible enough to use up to 1.5 A. The hysteretic current control is extremely fast and always stable without the need for any loop compensation. A maximum duty cycle of up to 99 percent enables use in applications where the input and output voltage are close to each other. -
Page 4: Circuit Description
ILD8150 80 V high side buck LED driver IC with hybrid dimming Circuit description Circuit description Operation BOOT Cboot Vout Iout Cout Rfltr Cfltr Typical application circuit Figure 1 2.1.1 Current regulation Figure 1 shows the typical application circuit. Current is controlled by the CS pin, which compares the voltage drop on R to internal references. -
Page 5: Cycle-By-Cycle Current Limitation
Cycle-by-cycle current limitation Because ILD8150 operates in current mode, it does not allow operation with higher current than it sets. Output current is limited cycle-by-cycle. Thus, it safely operates even when the LED output gets shorted. R short- circuit may cause damage. -
Page 6: Dimming
ILD8150 80 V high side buck LED driver IC with hybrid dimming Circuit description 2.2.3 Dimming Input dimming signal is PWM with minimal amplitude V with frequency f . Current accuracy over DIM_input dimming is high enough, and so is the feedback speed, that any input voltage change does not affect output current (no flicker). -
Page 7: Dim-To-Off
2.2.4 Dim-to-off ILD8150 turns the output stage off when the PWM dimming input signal duty cycle is less than , and on when the PWM dimming input signal duty cycle is higher than D , as shown in Figure 7. -
Page 8: Shut-Down
ILD8150 80 V high side buck LED driver IC with hybrid dimming Circuit description 2.2.6 Shut-down ILD8150 has a shut-down control pin SD. If the voltage on the pin is below low-threshold V during SD_IL recognition time more than t the IC goes to shut-down mode with low self-consumption current. -
Page 9: Ovp By Cs Pin
Figure 10 2.2.10 Microcontroller use A microcontroller may be used together with ILD8150. This enables control of dimming, to read out the output voltage and drive the IC into shut-down mode. The microcontroller use case is shown in Figure 11. OVP2... -
Page 10: Component Selection
ILD8150 80 V high side buck LED driver IC with hybrid dimming Circuit description Component selection 2.3.1 Current Sense (CS) resistor The average LED current is determined by the value of the CS resistor R . The mean CS threshold voltage is ��... -
Page 11: Input Capacitor C In Selection
ILD8150 80 V high side buck LED driver IC with hybrid dimming Circuit description The diode must be chosen so that its respective current ratings are higher than these values. 2.3.4 Input capacitor C selection The input current of the buck regulator is identical to the current through the MOSFET, i.e. it is pulsating and thus causes a ripple voltage at the input. -
Page 12: Design Example
ILD8150 80 V high side buck LED driver IC with hybrid dimming Circuit description input capacitor, output capacitor and inductor. Place the input capacitor close to the IC, as parasitic inductance can be minimized by minimizing trace lengths and using short and wide traces. Extra parasitic inductance between the input capacitor’s terminals and the IC’s V... -
Page 13: Select Switching Frequency
ILD8150 80 V high side buck LED driver IC with hybrid dimming Circuit description 2.5.2 Select switching frequency 80 kHz to 100 kHz may be a reasonable compromise between switching loss and inductor size. This needs to be verified by measurement of the finished design. -
Page 14: Boot Selection
ILD8150 80 V high side buck LED driver IC with hybrid dimming Circuit description For lower output voltage ripple a bigger output capacitor can be used. Because the value of this capacitor is relatively low even for low ripple demands, a MLCC capacitor is the best choice in terms of cost, lifetime and ESR. -
Page 15: Application Circuit
ILD8150 80 V high side buck LED driver IC with hybrid dimming Application circuit Application circuit This section provides more information about the reference design available. The board is configurable to have an output current in the range 250 mA to 1500 mA, with current adjustment by jumpers X9 A, B and C, as shown in Figure 16. -
Page 16: Pcb Layout
ILD8150 80 V high side buck LED driver IC with hybrid dimming Application circuit PCB layout PCB layout of the reference design Figure 15 Jumper X9A Jumper X9B Jumper X9C Output current (mA) 250 (+/-3 percent) 350 (+/-3 percent) 600 (+/-3 percent) -
Page 17: Measurement Results With Reference Design
LED current vs supply voltage ILD8150 provides high output current accuracy despite the changes in supply voltage. Figure 18 shows the output current vs supply voltage in the range 52 V to 70 V. Over the supply range, the output LED current only deviates in the range of 1 percent. -
Page 18: Dimming
ILD8150 80 V high side buck LED driver IC with hybrid dimming Measurement results with reference design Output current vs Input voltage 1000 1000 Input Voltage, [V] Output LED current vs supply voltage Figure 18 Dimming Table 2 Condition Input PWM frequency... -
Page 19: Soft-Start
ILD8150 80 V high side buck LED driver IC with hybrid dimming Measurement results with reference design Soft-start The soft-start process has two steps. Figure 20 shows the digital soft-start process with the steps described earlier. Iout Soft-start, output current... -
Page 20: Efficiency
ILD8150 80 V high side buck LED driver IC with hybrid dimming Measurement results with reference design Efficiency Efficiency measurement results in the input range 52 V to 70 V for 17 LEDs is shown in Figure 22. The efficiency is measured with different inductors –... -
Page 21: Output Current Ripple
ILD8150 80 V high side buck LED driver IC with hybrid dimming Measurement results with reference design Thermal image Figure 23 Output current ripple Figure 24 shows output current waveforms with capacitors of 10 nF and 4.7 µF accordingly. It can be seen that placing a 4.7 µF capacitor in parallel with the LED reduces output ripple current from 21.6 percent to 5.6... - Page 22 ILD8150 80 V high side buck LED driver IC with hybrid dimming Measurement results with reference design Output current waveform at 6.25 percent dimming level with electrolytic output 100 µF Figure 25 Application Note 22 of 28 V 1.0 2019-01-23...
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Page 23: Application With Flyback Converter Xdpl8218
54 V. So the ILD8150 hysteretic buck converter operates with a fixed input voltage of 54 V and has constant output current. ILD8150 can provide a wide dimming range from 0.5 to 100 percent, with high accuracy across all conditions. -
Page 24: Appendix A
ILD8150 80 V high side buck LED driver IC with hybrid dimming Appendix A Appendix A Table 3 Manufacturer Designator Value Description Manufacturer Part number BOOT 5000 Test-point THT, red Keystone 5000 Commercial-grade multi- 4.7 µF C3225X7S2A475K200AB layer ceramic chip capacitor... - Page 25 ILD8150 80 V high side buck LED driver IC with hybrid dimming Appendix A 23 R2 18.2 R 18.2R/200 V/1 percent Vishay CRCW120618R2FKEA Standard thick-film chip 24 R3 4.30 R Vishay CRCW12064R30FK resistor Standard thick-film chip 25 R4 4.30 R...
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Page 26: References
ILD8150 80 V high side buck LED driver IC with hybrid dimming References References Please refer to the ILD8150 datasheet for more information: Link to ILD8150 datasheet Application Note 26 of 28 V 1.0 2019-01-23... -
Page 27: Revision History
ILD8150 80 V high side buck LED driver IC with hybrid dimming References Revision history Document Date of release Description of changes version V1.0 November 2018 First release Application Note 27 of 28 V 1.0 2019-01-23... - Page 28 Infineon Technologies hereby disclaims dangerous substances. For information on the types © 2019 Infineon Technologies AG. any and all warranties and liabilities of any kind in question please contact your nearest Infineon All Rights Reserved. (including without limitation warranties of non- Technologies office.