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Infineon ILD8150, Операция, Руководство по конструкции и Эксплуатационные характеристики

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Application Note 

19 of 28 

V 1.0  

2019-01-23 

ILD8150 80 V high side buck LED driver IC with hybrid dimming 

Measurement results with reference design 

4.3

 

Soft-start 

The  soft-start  process  has  two  steps.  Figure 20 shows  the  digital  soft-start  process with  the  steps  described 
earlier. 

Iout

 

Figure 20 

Soft-start, output current  

4.4

 

Cycle-by-cycle current limitation 

Figure 21 shows the waveforms under short-circuit condition where the IC limits output current cycle-by-cycle. 

Iout

Vsw

 

Figure 21 

OCP waveforms 

Содержание ILD8150

Страница 1: ...brid 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 de...

Страница 2: ...2 Diode selection 13 2 5 3 CIN capacitor selection 13 2 5 4 COUT capacitor selection 13 2 5 5 Bootstrap capacitor Cboot selection 14 2 5 6 VCC capacitor CVCC selection 14 3 Application circuit 15 3 1...

Страница 3: ...h a wide range of supply voltages from 8 V to 80 V which gives flexibility and a clear advantage over existing 60 V solutions ILD8150 operates in hybrid dimming mode which helps to minimize LED color...

Страница 4: ...e drop on RCS to internal references Output current is proportional to the voltage drop on RCS When the CS voltage drops below VCSL the MOSFET switches on Current and voltage on RCS rise accordingly W...

Страница 5: ...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 RCS short circuit may cause damage...

Страница 6: ...er The IC operates in hybrid dimming mode The dimming curve is shown in Figure 6 which eliminates color shift and audible noise In the range from 12 5 to 100 percent it operates in analogue dimming mo...

Страница 7: ...ON DPWM_IN OFF 0 Figure 7 Dim to off 2 2 5 Soft start Soft start helps to reduce component stress when the application starts It further reduces under shoot of the input voltage The soft start is dig...

Страница 8: ...nC and VCBOOT is voltage deviation on the bootstrap capacitor The internal supply circuit provides voltage to the bootstrap capacitor VCboot 8 6 V which is a little higher than VCC This circuit helps...

Страница 9: ...emperature TVS voltage should be chosen as this does not affect operation and also limits output voltage to the right level RTVS and RPR limit the current through the TVS reduce dissipated power and r...

Страница 10: ...but on the other hand it leads to higher switching losses which has to dissipate the IC and efficiency decrease An optimal frequency in which switching losses are not so critical should be found The s...

Страница 11: ...pplications Due to the non linear I V characteristics of LEDs it is very difficult to estimate the ripple voltage with and without an output capacitor A generally accepted model is the approximation o...

Страница 12: ...ing traces far from the sensitive small signal traces The magnetic field from the inductor may cause noise on the CS path that could in turn lead to incorrect operation as double or triple pulses To a...

Страница 13: ...calculate diode currents the duty cycle D is needed 51 70 0 7285 1 0 2714 RMS diode current 1 0 2714 1 1 12 0 167 1 2 0 52 A Average diode current 1 0 2714 0 27 A For a design with variable number of...

Страница 14: ...en for low ripple demands a MLCC capacitor is the best choice in terms of cost lifetime and ESR Switching frequency is very high and can be visible so output capacitor may not be used just only 10 nF...

Страница 15: ...ers X9 A B and C as shown in Figure 16 The operating voltage range for the demo board can be from 8 V to 80 V Jumper J3 activates open load protection and prevents output over voltage to 60 V The boar...

Страница 16: ...ication circuit 3 2 PCB layout Figure 15 PCB layout of the reference design Jumper X9A Jumper X9B Jumper X9C Output current mA 250 3 percent V 350 3 percent V 600 3 percent V V 700 3 percent V 1050 3...

Страница 17: ...d LED current is 1 A The switching frequency is 85 kHz and the internal DMOS transistor on the duty cycle is 74 percent Iout Vsw Figure 17 Normal operation waveform 4 1 LED current vs supply voltage I...

Страница 18: ...ith reference design Figure 18 Output LED current vs supply voltage 4 2 Dimming Table 2 Condition Figure 19 Output current vs duty cycle 1000 991 990 995 996 900 920 940 960 980 1000 52 55 60 65 70 Ou...

Страница 19: ...Soft start The soft start process has two steps Figure 20 shows the digital soft start process with the steps described earlier Iout Figure 20 Soft start output current 4 4 Cycle by cycle current lim...

Страница 20: ...ns with fixed output voltage which is close to the output voltage and low input voltage deviation ripple a small inductor may be used In applications with wide output voltage range and input voltage r...

Страница 21: ...with the LED reduces output ripple current from 21 6 percent to 5 6 percent Iout Vsw Iout Vsw Figure 24 Output current ripple with COUT 10 nF left and with COUT 4 7 F right Some applications such as...

Страница 22: ...f 28 V 1 0 2019 01 23 ILD8150 80 V high side buck LED driver IC with hybrid dimming Measurement results with reference design Figure 25 Output current waveform at 6 25 percent dimming level with elect...

Страница 23: ...e XDPL8218 board operates with a universal AC input of 90 Vrms to 305 Vrms and provides a constant voltage of 54 V So the ILD8150 hysteretic buck converter operates with a fixed input voltage of 54 V...

Страница 24: ...10 p GCM series general purpose monolithic ceramic capacitor for automotive Murata GCM1885C1H100JA16 11 CS 5000 Test point THT red Keystone 5000 12 D1 MBR2H100SF SMD Schottky power rectifier 2 0 A 100...

Страница 25: ...ay CRCW12062R05FK 30 R10 1 33 R Standard thick film chip resistor Vishay CRCW12061R33FK 31 R11 1 33 R Standard thick film chip resistor Vishay CRCW12061R33FK 32 R12 0 R 0 R 200 V 20 m Vishay CRCW12060...

Страница 26: ...tion Note 26 of 28 V 1 0 2019 01 23 ILD8150 80 V high side buck LED driver IC with hybrid dimming References 7 References Please refer to the ILD8150 datasheet for more information Link to ILD8150 dat...

Страница 27: ...Note 27 of 28 V 1 0 2019 01 23 ILD8150 80 V high side buck LED driver IC with hybrid dimming References Revision history Document version Date of release Description of changes V1 0 November 2018 Fir...

Страница 28: ...intellectual property rights of any third party with respect to any and all information given in this application note The data contained in this document is exclusively intended for technically trai...

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