80 W offline LED driver with PFC
Contents
1. Start 150 kHz Stop 30 MHz Res BH 9 kHz VBH 30 kHz Sweep 4 ks 2115 pts koe cr 4 Doc ID 15327 Rev 2 28 43 Measurement UM0670 29 43 Figure 33 Average limit measurement from 150 kHz to 30 MHz lj gp 1000 mA Agilent 22 05 26 Dec 3 2008 Mkr1 15 68 MHz Ref 78 dBuV Atten 5 dB 32 69 dBuV EmiAv Log 18 dB Meas Uncal 1 H1 S2 3 FC AA Start 15 kHz Stop 30 MHz Res BH 9 kHz VBH 30 kHz Sueep 4 ks 2115 pts Figure 34 Quasi peak limit measurement from 9 kHz to 150 kHz lj gp 1000 mA Agilent 19 59 25 Dec 3 2008 Mkr1 163 368 kHz Ref 120 dBpV Atten 25 dB 54 26 dBuV EmiQP Log 16 dB DC Coupled Meas Unca Ml 52 5 3 FC AA Start 9 kHz Stop 150 kHz Res BH 288 Hz VBH 300 Hz Sueep 4 ks 2121 pts Doc ID 15327 Rev 2 a UM0670 Measurement 4 Figure 35 Quasi peak limit measurement from 150 kHz to 30 MHz Len 1000 mA Mkri 15 08 MHz Ref 70 dBpV Atten 5 dB 37 32 dBpV Start 150 kHz Stop 30 MHz Res BH 9 kHz VBH 30 kHz Sweep 4 ks 2115 pts Figure 36 Average limit measurement from 150 kHz to 30 MHz gp O mA Agilent 21 48 42 Dec 5 2008 Mkri 9 18 MHz Ref 70 dBpV Rtten 5 dB2. Power loss on the STPSC806D diode is Equation 17 Pioss p lavr p X Veg 0 8 x 0 7 0 56W where forward diode voltage was found for the average diode current 0 8 A in the datasheet see datasheet Section 11 References and related materials 4 Calculated junction diode temperature without using heat sink is Equation 18 Tj Pioss pX Ringo Rinca Taz 0 56 x 2 4 60 30 65 C Junction to case thermal resistance is available in the datasheet for the STPSC806D and case to ambient temperature is determined by the device package used In this case the TO 220 package is used and its thermal resistance is typically 60 C W Calculated junction diode temperature without using a heat sink is much lower than the maximum junction temperature for the STPSC806D and therefore this diode is suitable for the design One of the most important things to consider is proper inductor design The inductor size was calculated in Equation 8 but generally the inductor size by itself is not enough to ensure proper inductor design and therefore several additional equations are used for completing overall inductor construction First the inductor core size must be selected and for this selection it is very helpful to calculate the minimum area product using application parameters Minimum required core area product AP where the flux swing is limited by core saturation is Equation 19 4 LX Ipeak AG 1 6x 10 x 14x 1 4 3 AP
3. Ti UM0670 J User manual 80 W offline LED driver with PFC 1 Introduction The use of high power LEDs in lighting applications is becoming increasingly popular due to rapid improvements in lighting efficiency longer life higher reliability and overall cost effectiveness Dimming functions are more easily implemented in LEDs and they are more robust and offer wider design flexibility compared to other light sources For this reason a demonstration board for driving high brightness and power LEDs has been developed The STEVAL ILLO13V1 demonstration board is an 80 W offline dimmable LED driver with high power factor PF intended for fixed number of LEDs the overall design of which is described in detail in this user manual The LED current can be set to 350 mA 700 mA and 1000 mA using jumpers Additionally a dimming function using a PWM pulse width modulation signal is implemented as well allowing the user to set the LED brightness from 0 up to 100 The demonstration board can be ordered using order code STEVAL ILLO13V1 and is shown in Figure 1 STEVAL ILLO13V1 main features 80 W LED driver 350 mA 700 mA and 1 A LED current settings High efficiency 90 Wide input voltage range 88 to 265 VAC High power factor 0 99 for 110 VAC and 0 98 for 230 VAC Universal PWM input for dimming external board required Non isolated SMPS Brightness regulation between 0 and 100 EMI filter implemented EN55015 and EN61000 3
4. 27 Average limit measurement from 150 kHz to 30 MHz ligp 700MA 27 Quasi peak limit measurement from 9 kHz to 150 kHz en 700 mA 28 Quasi peak limit measurement from 150 kHz to 30 MHz ligp 700 mA 28 Average limit measurement from 150 kHz to 30 MHz ligp 1000 mA 29 Quasi peak limit measurement from 9 kHz to 150 kHz Len 1000 mA 29 Quasi peak limit measurement from 150 kHz to 30 MHz Len 1000MA 30 Average limit measurement from 150 kHz to 30 MHz ljEp50MA 30 Quasi peak limit measurement from 9 kHz to 150 kHz ljEp50MA 31 Quasi peak limit measurement from 150 kHz to 30 MHz l_egp OmMA 31 Proper startup circuit design liliis 32 Proper startup using diode D104 and capacitor C110 ee eee 33 Improper startup without using diode D104 and capacitor C110 33 Design improvement allowing zero dimming 000 cece eee eee 34 Voltage on capacitor C110 and output bus voltage of 400 V aa 35 Doc ID 15327 Rev 2 4 43 Getting started UM0670 2 Note 5 43 Getting started This section is intended to help designers begin evaluating the board quickly describing how the board should be connected with the load and how the jumpers adjust the output LED current As mentioned in the introduction the board has a nominal output power of 80 W and the output LED cur
5. Axial resistor 0 6 W 1 32 1 R120 15 kQ 1 SMD resistors 1206 33 1 R121 82 kQ 1 SMD resistors 1206 34 3 HE EE 330 kQ SMD resistors 1206 R125 35 2 R126 R127 20 kQ Axial resistor 0 6 W 36 1 R128 43 KQ SMD resistor 1206 E25 13 7 1 5 mm gap N67 37 1 T101 Transformer Primary 105 turns 2 x 0 3 Secondary 11 turns 1 x 0 3 38 1 Q101 STP8NM50 Power MOSFET STMicroelectronics STP8NM50FP 39 1 10102 BUX87 Bipolar transistor STMicroelectronics BUX87 40 2 Heat sink Heat sink for MOSFETs 41 2 R202 R207 1kQ SMD resistors 1206 42 2 R203 R209 3900 Q SMD resistors 1206 43 1 R204 1 50 0 6W Axial resistor 44 1 R205 2 7 Q 0 6 W Axial resistor 45 1 R206 2 2 0 0 6W Axial resistor 46 1 C201 22 uF 35V Electrolytic cap 47 1 C203 220 pf 63 V SMD capacitor 1206 48 1 C204 390 pF 63 V SMD capacitor 1206 49 1 C205 820 pF 63 V SMD capacitor 1206 50 1 C206 1 5 nF 63V SMD capacitor 1206 51 1 C207 330 pF 63 V SMD capacitor 1206 52 1 C208 0 47 uF 450V Electrolytic capacitor EPCOS B43827A5474M000 53 1 D202 STPSC806D Silicon carbide diode STMicroelectronics STPSC806D 54 1 D203 STTH1LO6A SMA package STMicroelectronics STTH1L06A 5514 m iR Jumper Two pin connector 56 2 JPJ1 JPJ2 Jumper Jumpers 57 1 J2 Socket Output socket 58 1 J3 Socket Output socket 5911 J4 Socket PWM socket 60 1 Q201 STF9NM50N Power MOSFET STMicroelectronics STF9NM50N silen fromm EEUU 1 13 43 The power MOSFET STF9NMBON ca
6. T pa ure LED current 350 mA DC 0 02 Viy 230V T T T T T LED current 360 mA DG 0 02 Viy 230W ZOOM for 2 duty cycle E 3 a 3 p 1 BH rs 166 r wd 58 po 168 r a Doc ID 15327 Rev 2 18 43 Measurement UM0670 9 9 1 Measurement Output waveform measurement Figure 13 shows the output LED current waveform The LED current was set to 350 mA and as shown the current ripple is 92 mA and the switching frequency for the modified buck converter is 125 kHz The input voltage was 230 VAC and 12 LEDs were used as the load OSTAR LED LE UW E3B see Section 11 References and related materials 6 The output LED current slightly varies with the output voltage as explained in detail in application note AN2928 Section 11 References and related materials 2 and therefore this design is optimal for a fixed number of LEDs The output LED current accuracy for different LED voltages is demonstrated in Figure 14 Figure 13 Output LED current waveform Len 350 mA T T T LED current Viy 230 V 12 LEDs used dimming 100 LED current ILED 350 mA Frequency 125 kHz VLED peak to peak 92 mA A 18 ps 188 m 19 43 Doc ID 15327 Rev 2 ky UM0670 Measurement Figure 14 Output LED cur
7. UM0670 Figure 29 Quasi peak limit measurement from 150 kHz to 30 MHz lj gp 350 mA Agilent 16 Mkri 15 08 MHz Ref 70 dBpV Rtten 5 dB 38 36 dBpV EmiQP CT dB Meas Uncal 1 WL 2 S3 FC RR Start 150 kHz Stop 30 MHz Res BH 9 kHz VBH 30 kHz Sweep 4 ks 2115 pts p o Figure 30 Average limit measurement from 150 kHz to 30 MHz Len 700 mA Agilent 03 31 56 Dec 3 2008 Mkr1 15 68 MHz Ref 78 dBuV 28 89 dBuV EmiAv Log 18 dB Atten 5 dB Start 150 kHz Res BH 9 kHz Stop 30 MHz Sueep 4 ks 2115 pts VBH 38 kHz 27 43 Doc ID 15327 Rev 2 a UM0670 Measurement Figure 31 Quasi peak limit measurement from 9 kHz to 150 kHz ljep 700 mA Agilent 22 Mkr1 163 368 kHz Ref 120 dBpV Atten 25 dB 53 76 dBuV EmiQP fr Log 16 dB Start 9 kHz Stop 150 kHz Res BH 288 Hz VBH 300 Hz Sweep 4 ks 2121 pts EEE st Figure 32 Quasi peak limit measurement from 150 kHz to 30 MHz l gp 700 mA Agilent 16 25 18 Dec 3 2008 Mkri 15 08 MHz Ref 70 dBpV Rtten 5 dB 41 58 dBpV EmiQP Log 10 dB Meas Uncal 1 WL 52 3 FC RR
8. tv a E tet puna Lt BN MOSFET du y t E dan cuore MOSFET drain T IV th y HD DD E a E i 3 50 ns 100 V B 50 ns 200 mA 1ys 198 V 1 us e ma 9 3 LED current ripple reduction The output LED current ripple can be reduced by increasing the output capacitor size For example inductor current ripple is 400 mA for the 100 nF 450 V output capacitor as shown in Figure 20 Thanks to the larger 470 nF capacitor used on the STEVAL ILLO13V1 the ky Doc ID 15327 Rev 2 22 43 Measurement UM0670 output current ripple is reduced to 92 mA see Figure 13 However there are some limitations for the capacitors used in dimmable applications as capacitors that are too large cause a decrease in dimming resolution minimum duty cycle is limited The 470 nF capacitor used on the STEVAL ILLO13V1 is a good compromise between lower output current ripple and good dimming resolution as illustrated in Figure 12 Figure 20 LED current ripple for the 100 nF output capacitor VIN 400 V VLED 230 V ILED AVR 343 mA output capacitor 100 nF 450 V ll ED RIPPLE 400 mA us cau cal ink ens Las nes descende iit amie AE ea idi EE Yas aia a SN lt a i VA Inductor current R PA j LED current v N N H NA ty I A IE Sense resistor voltage gt 4 3 440 mA Y 2 201 V 2 440 mA 9 4 Standard EN61000 3 2 measurement Figure
9. wine RM Bmax x CI 0 3x 420x 0 5x 10 0 2518cm where the constant is Cl Jyax X Cg x 107 420 x 0 5 x 10 The inductor core E25 from EPCOS was selected The minimum core cross section is 51 5 mm and the winding cross section is 61 mm see datasheet Section 11 References and related materials 5 and the calculated product area is Equation 20 AP Ay x Amin 61 x 51 52 O 31415cm The calculated product area is bigger than the minimum required product area and therefore the inductor core E25 can be used Doc ID 15327 Rev 2 40 43 Design calculation UM0670 41 43 The number of turns for the inductor is 3 N fr 1 6 x 10 172 AL 454 22 x 107 where the inductance factor Al for the E25 core and 2 mm gap is calculated Equation 21 Equation 22 1 Id 1 A lt K x 3 s 90x 073 2 54 22nH K4 70 see datasheet Section 11 References and related materials 5 K 0 73 see datasheet Section 11 References and related materials 5 s E25 core air gap mm The last step to complete the inductor design is to calculate the wire diameter Maximum inductor power dissipation is Equation 23 Tuax TA 70 30 Pmax Loss R 40 1W The wire resistance on the inductor is copper wire with diameter of 0 28 mm is chosen Equation 24 6 5x 172 axd 1 76x 10 x 314x 0 028 17 2MQ ly x N R px t px d where average turn length ly is written in the core datasheet see datasheet Sect
10. 0 3263 dBpy Start 150 kHz Stop 30 MHz Res BH 9 kHz VBH 30 kHz Sueep 4 ks 2115 pts fer H MAA Doc ID 15327 Rev 2 30 43 Measurement UM0670 31 43 Figure 37 Quasi peak limit measurement from 9 kHz to 150 kHz Len 0 mA Agilent 19 44 50 Dec 5 2 Mkri 79 500 kHz Ref 120 dBpV Ritten 25 dB 48 57 dBiV EmiQP Log 16 dB DC Coupled Meas Unca H1 2 x 3 FC RR Start 9 kHz Stop 150 kHz Res BH 200 Hz VBH 300 Hz Sweep 4 ks 2121 pts DP Figure 38 Quasi peak limit measurement from 150 kHz to 30 MHz ljep 0 mA Agilent 16 13 56 Dec 4 2008 Mkr1 15 68 MHz Ref 70 dBpV Atten 5 dB 12 4 dBuV EmiQP Log 16 dB Meas Uncal 1 H1 2 3 FC AA Start 15 kHz Stop 30 MHz Res BH 9 kHz VBH 30 kHz Sueep 4 ks 2115 pts oJ Doc ID 15327 Rev 2 a UM0670 Design features 10 Design features 10 1 Proper startup circuit design High PF boost converter design is described in the EVL6562A TM 80W Section 11 References and related materials 1 and this type of design typically includes a single electrolytic capacitor on the Ve pin of the L6562A to ensure proper startup The situation for the STEVAL ILLO13V1 is different as this inp
11. 2 compliant August 2009 Doc ID 15327 Rev 2 1 43 www st com Contents UM0670 Contents 1 Introduction uris sss ss e bin mvt de ee i at 1 2 Getting started Lussaanasssssans Re sans a Caco t ee EC AA 9 a 5 3 Design concept arcae 3 a ca R R eee AG e ta 6 4 STEVAL ILL013V1 technical details 9 5 Schematic diagram 4 eh hh neum mh nh 10 6 Bill of material 4123 xke oe a es dun dc ORE PRAAN WG ERA bl NG 12 7 STEVAL ILLO13V1 performance llll leee s 14 8 Dimming function ss s s s x x baa RECS Ee ec 17 9 Measurement i222 x ce oe BAKE dene Bec nnekseteeatadceecas 19 9 1 Output waveform measurement 0000 eee eee 19 9 2 Power MOSFET turn ON and OFF time 00 ee 22 9 3 LED current ripple reduction 0 0000 cee eee eee 22 9 4 Standard EN61000 3 2 measurement ee eee 23 9 5 EMI measurement EN55015 0 0 00 ees 26 10 Design features xs x eee ee eee C RR 32 10 1 Proper startup circuit design 32 10 2 Zero dimming design implementation rn r nn 33 11 References and related materials 36 Appendix A Design calculation e x cece ee 37 A 1 Design specifications for a modified buck convertor 37 12 REVISION history iua Oe eee ee C OR C Ree a ee 42 2 43 Doc ID 15327 Rev 2 ky UM0670 List of tables List of tables Table 1 LED values for different output c
12. 21 EN61000 3 2 analysis for LED current of 350 mA and Vin from 85 V to 160 VAC EN61000 3 2 analysis for LED current 350 mA at 12 LEDs VIN from 85 V to 160 V AC 1200 1000 800 Current Ei Real mA 600 m Limits 400 200 13 5 7 9 13579 13579 135789 13579 13579 85V 100V 110V 120V 140V 160V AM00406 23 43 Doc ID 15327 Rev 2 ky UM0670 Measurement Figure 22 EN61000 3 2 analysis for LED current of 350 mA and Vin from 180 V to 265 VAC EN61000 3 2 analysis for LED current 350 mA at 12 LEDs VIN from 180 V to 265 V AC 600 500 Current 400 Real mA 300 m Limits 13579 13579 13579 13579 13579 13579 180V 200V 220V 230V 240V 260V AM00407 Figure 23 EN61000 3 2 analysis for LED current of 700 mA and Vin from 85 V to 160 VAC EN61000 3 2 analysis for LED current 700 mA at 6 LEDs VIN from 85 V to 160 V AC Current mA Real B Limits 1357989 135789 1 3 5 79 13579 13579 135 7 9 85V 100V 110V 120V 140V 160V AM00408 Figure 24 EN61000 3 2 analysis for LED current of 700 mA and Vin from 180 V to 265 VAC EN61000 3 2 analysis for LED current 700 mA at 6 LEDs Vin from 180 V to 265 V AC Real Bl Limits 13579 13579 13579 13579 T 35 T NO 13579 180 V 200V 220V 230V 240 V 260 V AM00409 9 Doc ID 15327 Rev 2 24 43 Measurement UM0670 Figure 25 EN61000 3 2 analysis for LE
13. D 15327 Rev 2 38 43 Design calculation UM0670 39 43 Equation 10 2 2 2 2 Ipp 0 8 l Dx 0 2 1 0 21 RMS U d T Power MOSFET conduction loss is Equation 11 2 Poon laus X Rpscony7oec 0 21 x 0 756 0 159W Where the power MOSFET chosen is the STF9NM50N see datasheet Section 11 References and related materials 3 and its Rpg on for 70 C is Equation 12 Ros once Bogor c X 1 35 0 56 x 1 35 0 7560 Power MOSFET switching losses can be approximately calculated turn OFF time was measured 120 ns see Figure 19 Equation 13 B Vin X Imax X torr sw 400 x 1 4 x 120 x 10 7 x 50 x 10 WM 7 2 gt 1 68W The total power loss on the power MOSFET is 1 839 W so the heat sink can be calculated from following equation Equation 14 Tymax MOSFET lA O I HRS RIS thuc P incH T PtnHA And maximum heat sink to ambient resistance is Equation 15 TJMAX MOSFET TA 70 30 Rinna lt Ringo RincH ETTE 16 25 C W Prot The heat sink used in the power MOSFET on the STEVAL ILLO13V1 has a thermal resistance of 13 5 C W and therefore this heat sink is optimized for this design The last power component remaining to be calculated is the power diode The diode conducts during the OFF time and therefore its average current is Equation 16 MAX 0 8A lyn 1 4 0 6 2 1 02 x 5 l lava D 1 D x Doc ID 15327 Rev 2 ky UM0670 Design calculation
14. D current of 1000 mA and Vin from 85 V to 160 VAC EN61000 3 2 analysis for LED current 1 A at 4 LEDs VIN from 85 V to 160 V AC 1200 1000 Current B Real mA 600 m Limits 400 200 o Mel HN 13579 13579 13579 13579 13579 13579 85V 100 V 110V 120V 140 V 160 V AM00410 Figure 26 EN61000 3 2 analysis for LED current of 1000 mA and Vin from 180 V to 265 VAC EN61000 3 2 analysis for LED current 1 A at 4 LEDs Vin from 180 V to 265 V AC B Real B Limits 13579 13579 13579 13579 13579 13579 180V 200V 220V 230V 240V 260V AM00411 q 25 43 Doc ID 15327 Rev 2 UM0670 Measurement 9 5 4 EMI measurement EN55015 Figure 27 Average limit measurement from 150 kHz to 30 MHz lj ep 350 mA Agilent 98 26 02 Dec 4 2008 Mkr1 15 68 MHz Ref 76 dBpV Atten 5 dB 31 66 dBuV EmiAv a Log 18 dB Meap Uncal WL S2 3 FS RR Start 150 kHz Stop 30 MHz Res BH 9 kHz VBH 30 kHz Sueep 4 ks 2115 pts Figure 28 Quasi peak limit measurement from 9 kHz to 150 kHz lj Ep 350 mA Agilent 19 41 26 Mkri 103 368 kHz Ref 120 dBpV Atten 25 dB 54 14 dBpV Start 9 kHz Stop 150 kHz Res BH 200 Hz VBH 300 Hz Sweep 4 ks 2121 pts ed Doc ID 15327 Rev 2 26 43 Measurement
15. STEVAL ILL013V1 performance UM0670 Figure 9 Power factor for wide input voltage range 0 8 0 6 700 mA at 6 LEDs Power factor 350 mA at 12 LEDs 1Aat4LEDs 0 4 0 2 0 85 100 110 120 140 160 180 200 220 230 240 265 Input voltage V AM00397 Figure 10 Detailed power factor for wide input voltage range 0 99 0 98 700 mA at 6 LEDs Power factor 350 mA at 12 LEDs 0 97 1Aat4LEDs 0 96 0 95 85 100 110 120 140 160 180 200 220 230 240 265 Input voltage V AM00396 15 43 Doc ID 15327 Rev 2 ky UM0670 STEVAL ILL013V1 performance Figure 11 Total harmonic distortion for wide input voltage range THD 12 00 10 00 8 00 6 00 4 00 2 00 0 00 85 100 110 120 140 160 180 200 220 230 240 265 Input voltage V 700 mA at 6 LEDs 350 mA at 12 LEDs 1Aat4LEDs AM00398 Doc ID 15327 Rev 2 16 43 Dimming function UM0670 8 17 43 Dimming function LEDs as a light source are very often used in applications where the brightness regulation is required Their biggest advantage is that their minimum brightness can be easily regulated by changing their current and they are stable even at very low brightness Generally there are two basic concepts regarding how the brightness is regulated The first is called analog dimming which means that the br
16. any problem because if the Doc ID 15327 Rev 2 ky UM0670 Design features voltage on the emitter of Q102 is below the limit established by voltage divider R125 and R128 upper limit set to 16 6 V the transistor is opened and charges C110 and C107 Therefore it is possible to change the brightness between 0 and 100 on the STEVAL ILLO13V1 The real measurement is shown in Figure 43 and it is evident that the supply voltage on capacitor C110 is not below 12 5 V during no brightness Figure 42 Design improvement allowing zero dimming 4 Supplying PWM generator with ST7LITEU05 Vc 16V Supplying L6562A in modified BUCK converter ZCD COMP INV Mee L6562A GD Vout 400 V MULT GND CS O Allowing 0 dimming AM00401 Doc ID 15327 Rev 2 34 43 Design features UM0670 Figure 43 Voltage on capacitor C110 and output bus voltage of 400 V STEVAL ILL013V1 with 0 dimming Vout T HAH J 1si100v 3 1s5 8Vv 35 43 Doc ID 15327 Rev 2 UM0670 References and related materials 11 References and related materials 1 STMicroelectronics EVL6562A TM 80W 80 W high performance transition mode PFC evaluation board data brief see www st com 2 STMicroelectronics AN2928 Modified buck converter for LED applications application note see www st co
17. determined using the following equation Equation 3 t 6 OFF 16x 10 Cou s LE on 92 v se95nF Cana Cog 2 1x Bans 2 1x 3900 n Therefore the capacitors C204 and C206 have the following size C204 390 pF C206 1 5nF Doc ID 15327 Rev 2 ky UM0670 Design calculation Resistor R202 limits the charging current and should be in the following range Equation 4 V V Vap MAx Vzcb CLAMP Vr Veo MIN ZCD CLAMP J lt Rage lt R203 X VZCD CLAMP VzCD CLAMP lzcp MAX T ED MENS 203 Equation 5 15 5 7 0 7 E R2 lt 3900 x 2 5 7 e 0 01 2355 ud 3900 Equation 6 750 lt Rag lt 2326 A 1 KQ resistor is chosen for R202 Capacitor C203 should be lower than 1 25 nF and therefore a value of 220 pF was chosen Equation 7 VzCD CLAMP 5 7 2189x110 1 25nF Cong lt C204 II C206 15 5 7 0 7 Vap cmax Vzcp camp VP C203 220 pF Inductor size is calculated using following equation Equation 8 ViepXtorr _ 80x 16x 10 Z 1 6mH 2x uas lavn 2x 1 4 1 Two sense resistors are connected in parallel and their size is calculated Equation 9 V cs _ 1 08 The output LED current of 1 A was precisely set by adjusting resistors R204 and R206 and therefore their optimal resistance values are 1 5 Q and 2 20 R204 1 5 Q R206 2 2Q0 In the next step the power MOSFET and its heat sink are calculated The power MOSFET RMS current is derived using the following equation Doc I
18. en DE1E3KX102MA5B 8 1 C102 470 nF 265 VAC X2 capacitor EPCOS B32922C3474K 9 12 C103 C104 220nF 265 VAC X2 capacitor EPCOS B32922C3224M 10 1 C105 10 nF 63V SMD capacitor 1206 11 2 C106 C202 100 nF 63 V SMD capacitor 1206 12 1 C107 10 UE 735 V Electrolytic capacitor 13 2 C108 C109 12nF 63V SMD capacitor 1206 14 1 C110 33 UE 35 V Electrolytic capacitor 15 1 C111 2200 nF 25 V X7R SMD 1206 ceramic AVX 12063C225KAT2A capacitor 16 1 C112 150 nF 50 V SMD capacitor 1206 17 1 C113 47 uF 450 V Electrolytic capacitor EPCOS B43501A5476M000 18 1 D101 18 V 0 5W Zener diode D102 D104 19 4 D201 D204 1N4148 SMD diode STMicroelectronics 20 1 D103 STTH1LO6U SMB package i STTH1LO6U 2112 U101 U201 L6562A PFC controller STMicroelectronics L6562AD R101 R102 22 4 R103 R104 1MQ SMD resistors 1206 23 1 R105 15 kQ SMD resistors 1206 2412 R106 R107 270 kQ SMD resistors 1206 2512 R108 R109 47 Q SMD resistors 1206 R110 R116 26 3 R208 47 kQ SMD resistors 1206 27 2 R111 R122 0Q SMD resistors 1206 28 3 eee 19 1 SMD resistors 1206 R114 2912 R115 R201 33 Q SMD resistors 1206 ky Doc ID 15327 Rev 2 12 43 Bill of material UM0670 Table 3 STEVAL ILL013V1 demonstration board bill of material continued I Q Reference Part Note Manufacturer Order code 30 1 R117 22 kQ SMD resistors 1206 31 12 R118 R119 1 MQ 1
19. er core used E25 Supply voltage provided for external PWM generator Board size 130 mm x 60 mm x 27 mm Optional external PWM generator non isolated Full brightness if PWM generator is not connected Two output connectors for LEDs High efficiency 90 Wide input voltage range 88 V to 265 VAC Brightness regulation between 0 and 100 EMI filter implemented EN55015 and EN61000 3 2 tested Figure 5 STEVAL ILLO13V1 with PWM module Doc ID 15327 Rev 2 ky Schematic diagram UM0670 Schematic diagram 5 High PFC boost converter with the L6562A Figure 6 cOvYOOIAV D ON 28 GAGE OL OL OL lela 0214 vilt ELLY zka ww C 0 X Z sun GOL eWNd ZON deb ww G L ZXELXGCA d 4e 7 G Ha OV A OSZ LA JUL am U of OGL 4 ET SOLY E8XNA N yuisj29H In gg 49019 LOLO 2010 OSY HLO T du oxose 404r L ozz GZLH ML d40SINN8dIS LO m LOLO vota ELLO L O02 4 014 12 LU OY OEE Pala OW I pre OA 022 W Lua GL LY qu ost zziu Mie Z0Ld L oll eal ON T Ox OZ OA OE OW L Nil Ox 027 L AAR 9ecLdl ezia SIH LY e U Lv HUGH 9019 vw 901IHLLS e am 60LH 6012 K T Ki LOLL 9 9 hd 9 860L07p dUcl COL JU OGG 007 cold B0lH 8012 H COLO IHL V L HW ZZ XZONO KS WW Q X L sun LL Arep
20. he module is not used the LED brightness is set to maximum level 100 brightness Finally connect an input voltage to the demonstration board between 88 VAC and 265 VAC and the LEDs begin illuminating The LEDs cannot be connected during operation when the input voltage is connected to the demonstration board This is because in this case the output capacitor C208 0 47 uF is charged to 400 V and can cause uncontrolled peak LED current Table 1 LED values for different output currents Output LED current mA Output LED voltage V dep T 350 228 65 700 114 32 1000 80 23 Table 2 Output LED current adjustment on the demonstration board Jumper 350 mA 700 mA 1000 mA JP1 Not connected Connected Not connected JP2 Not connected Connected Not connected JP3 Not connected Not connected Connected JP4 Not connected Not connected Connected Doc ID 15327 Rev 2 UM0670 Design concept 3 Figure 2 Design concept The STEVAL ILLO13V1 block schematic is illustrated in Figure 2 As shown the design is divided into two main topologies The first is a high PF power factor boost converter and the second is a modified buck converter As an additional board any external PWM generator can be used for LED brightness regulation If no PWM generator is connected to the STEVAL ILLO13V1 the LED brightness is pre adjusted to 100 There are two main reasons the high PF boost converter is des
21. igh PF boost converter design concept a Supplying PWM generator with ST7LITEU05 ie Supplying L6562A in modified BUCK converter STTH1L06 Vin 88 V to 265 V AC DFP Vout 400 V Input EMI filter T Ga 0 dimming AM00413 7 43 Doc ID 15327 Rev 2 ky UM0670 Design concept Figure 4 Modified buck converter with dimming design concept Vc 16 V generated by the first converter Additional board Vin 400 V generated by the first converter O STPSC806D 80 W LEDs Ki gt for brightness regulation PWM signal 0 to 100 prosper I mel Fixed off time External module network gt esc X AM00414 lt Doc ID 15327 Rev 2 8 43 STEVAL ILLO13V1 technical details UM0670 4 9 43 STEVAL ILL013V1 technical details 80 W LED driver 350 mA 700 mA and 1 A LED current settings PF 0 99 with Vin 110 V or PF 0 98 with Vin 230 V THD total harmonic distortion 4 6 and Vin 110 V or THD 10 3 and Vin 230 V High PFC boost converter operating in transition mode Modified buck converter working in CCM and using FOT network Switching frequency f 125 kHz 350 mA modified buck converter Switching frequency f 69 kHz 700 mA modified buck converter Switching frequency f 2 55 kHz 1000 mA modified buck converter The same inductor and transform
22. ightness is regulated by changing the continuous forward LED current This concept is not used on the STEVAL ILLO13V1 The second solution is to use a low frequency 200 Hz PWM signal and change the brightness by pulse width modulation This is the approach used in the design of the STEVAL ILLO13V1 Any external PWM generator can be used for brightness regulation but it should be taken into account that the STEVAL ILLO13V1 is not isolated In order to demonstrate the dimming function on the STEVAL ILLO13V1 an external PWM generator using STMicroelectronics ST7LITEU05 microcontroller was connected to the board and the output LED current was measured The microcontroller generates a PWM signal with a frequency of 250 Hz The duty cycle is set by a potentiometer from 096 up to 100 The result with duty cycles of 50 10 and 2 is shown in Figure 12 The input voltage was in this case 230 VAC and the output LED current was set to 350 mA It is also possible to achieve LED brightness regulation below 2 In this case the nominal LED current is slightly decreased Doc ID 15327 Rev 2 ky UM0670 Dimming function Figure 12 Output LED current dimming capability r T T T T T T T T T Dimming feature LED current 350 mA DC 2 0 5 Viy pe V r T T T T T T T T T Dimming feature LED current 350 mA DC 2 0 1 Vy 230 V B rs 106 r E ra 1893 ne i T T T T
23. igned on the STEVAL ILLO13V1 demonstration board The first is the requirement for lighting equipment with an input active power higher than 25 W to comply with standard EN61000 3 2 harmonic current distortion Thanks to the high PF converter compliance to the standard is achieved with no difficulty The second reason is that a high input voltage in this case 400 V is needed for the modified buck converter because it is in fact a buck converter and thus the input voltage must be higher than the output voltage The output LED voltage can be up to 228 V as was shown in Table 1 An additional advantage of the high PF converter is its wide input voltage range This allows the demonstration board to be used either in either the European or US markets A more detailed description of the high PF boost converter is provided in the EVL6562A TM 80W data brief see Section 11 References and related materials 1 The second converter is designed as a constant current source as it ensures the best lighting performance from the LEDs Concerning the topology the modified buck has been chosen modified insofar as the power switch is connected to ground instead of the high side switch as in a standard buck topology and therefore it is easier to control the switch The design uses a FOT fixed off time network operating in CCM continuous conduction mode and thanks to this principle the overall solution is very simple and cost effective All equatio
24. ion 11 References and related materials 5 The power dissipation on the wire is Equation 25 Pwine Rx l vp 17 2x 10 x 17 17 2mw The power loss in the wire is much lower than the maximum power loss in the inductor and so a wire with a diameter of 0 28 mm is suitable for this inductor Doc ID 15327 Rev 2 ky UM0670 Revision history 12 Revision history Table 4 Document revision history Date Revision Changes 15 May 2009 1 Initial release 10 Aug 2009 2 Document reformatted corrected typing error in Figure 7 added note below Table 3 Doc ID 15327 Rev 2 42 43 UM0670 Please Read Carefully Information in this document is provided solely in connection with ST products STMicroelectronics NV and its subsidiaries ST reserve the right to make changes corrections modifications or improvements to this document and the products and services described herein at any time without notice All ST products are sold pursuant to ST s terms and conditions of sale Purchasers are solely responsible for the choice selection and use of the ST products and services described herein and ST assumes no liability whatsoever relating to the choice selection or use of the ST products and services described herein No license express or implied by estoppel or otherwise to any intellectual property rights is granted under this document If any part of this document refers to any third
25. m 3 STMicroelectronics STF9NM50N N channel second generation MDmesh power MOSFET datasheet see www st com 4 STMicroelectronics STPSC806D 600 V power Schottky silicon carbide diode datasheet see www st com 5 EPCOS B66317 Ferrites and accessories E25 13 7 EF25 core and accessories datasheet see www epcos com 6 OSRAM LE UW E3B OSTAR Lighting with optics datasheet see www osram os com Doc ID 15327 Rev 2 36 43 Design calculation UM0670 Appendix A Design calculation A 1 37 43 The aim of this section is to demonstrate how the components for the modified buck converter are calculated Design calculation follows precisely the equations used in application note AN2928 Section 11 References and related materials 2 Therefore please refer to this application note for more information Design specifications for a modified buck convertor Vin 400 V Vigp 80 V lwn gt T Imax 1 4 A la 0 6 A f 50 kHz TA 30 C TJMAX MOSFET 70 C Modified buck converter working with duty cycle output LED current is 1 A Equation 1 V D ER 0 3 Vin 400 Calculated OFF time for selected switching frequency of 50 kHz is Equation 2 Geb piba Torr f 50000 OHS Now the FOT network should be calculated First resistor R203 is selected R203 3900 Q Two capacitors in parallel C204 and C206 are used for the 1 A output LED current jumper JP3 is connected and their size is
26. n be replaced by STF10NM60N Doc ID 15327 Rev 2 q UM0670 STEVAL ILL013V1 performance 7 STEVAL ILL013V1 performance Figure 8 shows the efficiency of the STEVAL ILLO13V1 measured also with an external PWM generator for the output LED current 350 mA 700 mA and 1 A over the entire input voltage range Measured efficiency for the input voltage of 230 V was above 90 90 49 for the 350 mA output LED current 90 53 for the 700 mA output LED current and 90 3 for the 1 A output LED current Efficiency for the input voltage of 110 V was above 87 88 05 for the 350 mA output LED current 88 2 for the 700 mA output LED current and 87 37 for the output LED current of 1 A Measured PF for the output LED current of 350 mA 700 mA and 1 A is shown in Figure 9 and Figure 10 PF for the input voltage of 110 VAC is 0 99 and 0 98 for the input voltage of 230 VAC THD is demonstrated in Figure 11 and as it can be observed is below 12 over the whole input voltage range Note LE UW E3B OSTAR LEDs from OSRAM were used as the load see Section 11 References and related materials 6 Figure 8 Efficiency over the whole input voltage range 100 00 90 00 80 00 70 00 7 60 00 700 mA at 6 LEDs Efficiency 50 00 350 mA at 12 LEDs 40 00 1 A at 4 LEDs 30 00 20 00 10 00 0 00 85 100 110 120 140 160 180 200 220 230 240 265 Input voltage V AM00395 ky Doc ID 15327 Rev 2 14 43
27. ns needed for proper modified buck converter design are described in application note AN2928 see Section 11 References and related materials 2 STEVAL ILL013V1 block schematic HIGH POWER FACTOR BOOST CONVERTER MODIFIED BUCK CONVERTER STTH1L06 Input 400 V 80 W LOAD filter Vin 88 V to STP8NM50FP STPSC806D 265 V AC PF controller 4 L6562A STF9NM50N EXTERNAL PWM GENERATOR Microcontroller FA ST7LITEU05 Bright regulation AM00400 Doc ID 15327 Rev 2 6 43 Design concept UM0670 Figure 3 illustrates a high PF boost converter design concept Two additional features are implemented in the application and these improvements are shown in the blue segments The first improves circuit behavior during startup see Section 10 1 for a description and the second allows the dimming of the LED down to 0 or no LED brightness description provided in Section 10 2 Figure 4 shows the design concept of a modified buck converter with a dimming function The output LED current is adjusted by setting the proper sense resistor size via the jumpers to adjust maximum LED current together with the proper setting of the capacitor used in the FOT network adjust minimum LED current The external PWM generator provides a PWM signal between 0 and 100 for brightness regulation This signal is connected through a diode to the current sense pin and allows control of LED brightness Figure3 H
28. party products or services it shall not be deemed a license grant by ST for the use of such third party products or services or any intellectual property contained therein or considered as a warranty covering the use in any manner whatsoever of such third party products or services or any intellectual property contained therein UNLESS OTHERWISE SET FORTH IN ST S TERMS AND CONDITIONS OF SALE ST DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY WITH RESPECT TO THE USE AND OR SALE OF ST PRODUCTS INCLUDING WITHOUT LIMITATION IMPLIED WARRANTIES OF MERCHANTABILITY FITNESS FOR A PARTICULAR PURPOSE AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION OR INFRINGEMENT OF ANY PATENT COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT UNLESS EXPRESSLY APPROVED IN WRITING BY AN AUTHORIZED ST REPRESENTATIVE ST PRODUCTS ARE NOT RECOMMENDED AUTHORIZED OR WARRANTED FOR USE IN MILITARY AIR CRAFT SPACE LIFE SAVING OR LIFE SUSTAINING APPLICATIONS NOR IN PRODUCTS OR SYSTEMS WHERE FAILURE OR MALFUNCTION MAY RESULT IN PERSONAL INJURY DEATH OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE ST PRODUCTS WHICH ARE NOT SPECIFIED AS AUTOMOTIVE GRADE MAY ONLY BE USED IN AUTOMOTIVE APPLICATIONS AT USER S OWN RISK Resale of ST products with provisions different from the statements and or technical features set forth in this document shall immediately void any warranty granted by ST for the ST product or service described herein and shall not create or extend in any manner whatsoe
29. rent can be set to 350 mA 700 mA or 1 A The LEDs are connected to one string Basically this means if the LED current is set to 350 mA then the LED voltage should be approximately 228 V in order to provide output power of 80 W If the LED current is set to 700 mA then the LED voltage should be around 114 V Finally if the LED current is set to 1 A then the LED voltage should be about 80 V Assuming that a high brightness LED has typically a 3 5 V forward voltage drop the number of LEDs for the 350 mA output current is 65 for the 700 mA output current it is 32 and for the output current of 1 A it is 23 see Table 1 Of course designers must recalculate the number of LEDs in cases where the LED has a forward voltage drop other than 3 5 V If the output LED voltage is different than that given in Table 1 output LED current precision will be influenced so is recommended that the total forward voltage drop across all the LEDs is as close as possible to the calculated output voltages shown in Table 1 Connect the LED string to the board using connector J2 or J3 being careful to observe the correct LED polarity anode and cathode Set the output LED current to 350 mA 700 mA or 1 A based on how many LEDs are connected to the output The output LED current is set using jumpers JP1 JP2 JP3 and JP4 in accordance with the connection settings specified in Table 2 It is not necessary to connect a dimming module with a PWM signal because if t
30. rent for different LED voltages lj gp 350 mA VLED VS ILEp for nominal LED current 350 mA 450 400 350 LED 300 Bw 250 200 150 100 50 0 350 mA 174 193 211 230 250 LED voltage V AM00399 Figure 15 shows the output LED current waveform for the LED current of 700 mA The current ripple is in this case 333 mA and the switching frequency for the modified buck converter is 69 kHz The input voltage was 230 AC and 6 LEDs were used as the load OSTAR LED LE UW E3B see Section 11 References and related materials 6 The output LED current accuracy for the different LED voltages is shown in Figure 16 Figure 15 Output LED current waveforms Len 700 mA T T ming 100 T T LED current Vin 230 V 6 LEDs used dim RIT LED current ilag pie ILED 700 mA Frequency 69 kH Vi pp peak to peak 333 mA N 20 ps 288 mA ky Doc ID 15327 Rev 2 20 43 Measurement UM0670 Figure 16 Output LED current for different LED voltage lj gp 700 mA LED mA current Vi gp VS lj gp for nominal LED current 700 mA 800 700 600 500 400 300 200 100 700 mA 82 101 121 139 LED voltage V AM00404 Figure 17 shows the output LED current waveform for the output LED current of 1000 mA The current ripple is 433 mA and the s
31. t voltage range 2 0 cee ee 15 Total harmonic distortion for wide input voltage range llle 16 Output LED current dimming capability llle 18 Output LED current waveform Len 350 MA ee 19 Output LED current for different LED voltages l gp 350 MA onna 000 20 Output LED current waveforms gn 700 MA 1 eee 20 Output LED current for different LED voltage ligo 700 mA lisse 21 Output LED current waveform li gg 1000 MA 1 eee 21 Output LED current for different LED voltage Len 1000 MA nnna vrir even 22 Power MOSFET turn ON and OFF measurement 00 00 cece eee 22 LED current ripple for the 100 nF output capacitor liliis eese 23 EN61000 3 2 analysis for LED current of 350 mA and Vin from 85 V to 160 VAC 23 EN61000 3 2 analysis for LED current of 350 mA and Vin from 180 V to 265 VAC 24 EN61000 3 2 analysis for LED current of 700 mA and Vin from 85 V to 160 VAC 24 EN61000 3 2 analysis for LED current of 700 mA and Vin from 180 V to 265 VAC 24 EN61000 3 2 analysis for LED current of 1000 mA and Vin from 85 V to 160 VAC 25 EN61000 3 2 analysis for LED current of 1000 mA and Vin from 180 V to 265 VAC 25 Average limit measurement from 150 kHz to 30 MHz ligp 350MA 26 Quasi peak limit measurement from 9 kHz to 150 kHz en 350MA 26 Quasi peak limit measurement from 150 kHz to 30 MHz Len 350 MA
32. the L6562A operates The voltage on capacitor C110 is added to the voltage on capacitor C107 through diode D104 and as soon as the voltage on capacitor C110 also reaches the turn ON threshold the L6562A starts operating continuously and the output voltage reaches 400 V as shown in Figure 40 Figure 39 Proper startup circuit design maa AM00412 Doc ID 15327 Rev 2 32 43 Design features UM0670 10 2 33 43 Figure 40 Proper startup using diode D104 and capacitor C110 Proper startup VIN 110 V C110 AND D104 used HAHA 1 2 s 188 V 3 2850V J 2s 5 9V Figure 41 Improper startup without using diode D104 and capacitor C110 Wrong startup VIN 110 V C110 AND D104 not used La a a a a a AHHH J 5 s 100 v 3 5s5 0V Zero dimming design implementation During zero dimming duty cycle is 0 the high PF boost converter is in burst mode because there is zero load During this mode capacitors C107 and C110 are charged only in short pulses C107 is also slightly charged via resistor from the input voltage but it is not enough and therefore do not have enough energy to also supply the PWM generator and the second L6562A controller used for the modified buck converter The circuit shown in Figure 42 allows brightness changes down to 0 without
33. uooeg 10 43 Doc ID 15327 Rev 2 UM0670 Schematic diagram Modified buck converter with the L6562A Figure 7 E0700NV M90 012 i M90 U ZZ M 90 09 kd kd kad 9 9 9 9 902H GOZH vozu Ae9 sust goog L adose ONE al 9020 5029 voco EUe 4d 06 HIdINNP e uadwnr e HIdNNNZ HIdNNI 6 Z020 dr lar adr pdr o Ho 1 z OM 1 AC 0cc OM L zoey e gozo 8r LEN L v 8FLPNL toza 3 V90TLHLIS l 1020 PART 5 2 Y O EE 6024 8 goza A Cc ee LOZU OF NOSWN64LS 78 Lozo le sun ZZ HW9 L vz9S911 jeubis Lozn Buwwip il 4 OM l NMd 8024 L027 E Q9080Sd1S wy AOS Jr 2470 zoza N eT L eozo woof J Z wad LOZO 9 P a 9L 007 Doc ID 15327 Rev 2 11 43 UM0670 Bill of material 6 Bill of material Table 3 STEVAL ILL013V1 demonstration board bill of material I Q Reference Part Note Manufacturer Order code 1 1 J1 Socket Input socket 2 11 F1 Fuse 2 5 A 250 V 3 11 F1 Fuse socket Socket 4 1 NTC 10Q NTC thermistor EPCOS B57235S100M 5 1 TR1 2x22mH 1A Common mode choke EPCOS B82732R2102B030 6 1 BR1 1A 250V Diode bridge 7 l1 C101 1nF 250VAC Y1 capacitor ka
34. urrents 1 2 liliis 5 Table 2 Output LED current adjustment on the demonstration board llle sess 5 Table 3 STEVAL ILLO13V1 demonstration board bill of maternal rann ir rvnr 12 Table 4 Document revision history sesse K KK X ER R K K K ER R K eae 42 ky Doc ID 15327 Rev 2 3 43 UM0670 List of figures List of figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 Figure 19 Figure 20 Figure 21 Figure 22 Figure 23 Figure 24 Figure 25 Figure 26 Figure 27 Figure 28 Figure 29 Figure 30 Figure 31 Figure 32 Figure 33 Figure 34 Figure 35 Figure 36 Figure 37 Figure 38 Figure 39 Figure 40 Figure 41 Figure 42 Figure 43 STEVAL ILLO13V1 demonstration board aurana n arrena 1 STEVAL ILLO13V1 block schematic llle 6 High PF boost converter design concept 00 e eee tees T Modified buck converter with dimming design concept 0 0 0 0 eee eee eee 8 STEVAL ILLO13V1 with PWM module 0 0 0 ee 9 High PFC boost converter with the L6562A 00002 eee 10 Modified buck converter with the L6562A 1 1 e 11 Efficiency over the whole input voltage range 0 0 eee ee ee 14 Power factor for wide input voltage range eee tee 15 Detailed power factor for wide inpu
35. ut capacitor also supplies the second L6562A driver used for controlling the modified buck converter and also provides a supply voltage for the PWM generator Generally this means that there is always some additional current discharging the input capacitor during startup and therefore the high PF boost converter does not start properly if the low input AC voltage is applied to the board This is due to there being insufficient energy in the input capacitor to guarantee proper startup The waweforms which illustrate this situation are given in Figure 41 circuit without capacitor C110 and diode D104 As soon as the input voltage reaches the turn ON threshold the L6562A starts operating and the input voltage on the Vcc pin is decreased As soon as it reaches the turn OFF threshold the capacitor is charged again and the L6562A stops operating This behavior is repeated and so after a short period the output voltage should reach 400 V However this is not possible due to low energy in the input capacitor on the Vee pin This problem is solved by adding capacitor C110 and diode D104 to the original schematic as shown in Figure 39 Thanks to this configuration the input capacitor C107 on the Vcc pin is not discharged because it is supplying the PWM generator and second converter Capacitor C110 is used to provide supply voltage to the PWM generator and the second converter Capacitor C110 is charged via a capacitive supply source connected to the ZCD when
36. ver any liability of ST ST and the ST logo are trademarks or registered trademarks of ST in various countries Information in this document supersedes and replaces all information previously supplied The ST logo is a registered trademark of STMicroelectronics All other names are the property of their respective owners 2009 STMicroelectronics All rights reserved STMicroelectronics group of companies Australia Belgium Brazil Canada China Czech Republic Finland France Germany Hong Kong India Israel Italy Japan Malaysia Malta Morocco Philippines Singapore Spain Sweden Switzerland United Kingdom United States of America www st com 43 43 Doc ID 15327 Rev 2 ky
37. witching frequency for the modified buck converter is 55 kHz The input voltage was 230 VAC and 4 LEDs were used as the load OSTAR LED LE UW E3B see Section 11 References and related materials 6 The output LED current accuracy for the different LED voltages is shown in Figure 18 Figure 17 Output LED current waveform Len 1000 mA LED current Vin 230 V 4 LEDs used dimming 100 LED current opps ILED 1000 mA Frequency 55 kHz Vi pp Peak to peak 433 mA 20 ps 200 mA 21 43 Doc ID 15327 Rev 2 UM0670 Measurement Figure 18 Output LED current for different LED voltage ljep 1000 mA Vi gp vs Ip gp for nominal LED current 1 A 1200 1000 LED 800 current mA 600 A 400 200 0 63 84 103 122 LED voltage V AM00405 9 2 Power MOSFET turn ON and OFF time The power MOSFET turn ON and OFF time is shown in Figure 19 Turn ON time is approximately 50 ns and turn OFF time is approximately 120 ns OFF time is used in Equation 13 in the appendix Figure 19 Power MOSFET turn ON and OFF measurement T T T I T T T T T I T T Power MOSFET turn ON losses Power MOSFET turn OFF losses MOSFET drain source e MOSFET drain source voltage 1 Jem ra amd n pud 1 7 v 4
Download Pdf Manuals
Related Search