EVBUM2160 - NCP1255 25 W Evaluation Board User`s Manual
Contents
1. DIELECTRIC RATING 2000VAC 1 minute tested by applying 2500VAC for 1 second between pins 1 7 2 6 11 12 500VAC 1 minute tested by applying 625VAC for 1 second between pins 1 2 INDUCTANCE 1 00 mH 10 10kHz 100mVAC OmADC 1 6 Ls SATURATION CURRENT 2 5A saturating current that causes 20 rolloff from initial inductance LEAKAGE INDUCTANCE 6 0uH typ 12 0uH max 100kKHz 100mVAC 1 6 7 8 11 12 Ls TURNS RATIO 1 6 7 11 2 583 1 00 tie 7 8 11 12 1 1 6 2 5 5 166 1 00 1 1 3 3 6 1 1 00 1 Designed to meet Class 2 requirements Wire insulation amp ROHS status not affected by wire color Wire insulation color may vary depending on availability Unless otherwise specified tolerances are as follows Angles 1 Fractions 1 64 Decimals 005 127mm ON Semiconductor and Q are registered trademarks of Semiconductor Components Industries LLC SCILLC SCILLC owns the rights to a number of patents trademarks copyrights trade secrets and other intellectual property A listing of SCILLC s product patent coverage may be accessed at www onsemi com site pdf Patent Marking pdf SCILLC reserves the right to make changes without further notice to any products herein SCILLC makes no warranty representation or guarantee regarding the suitability of its products for any particular purpose nor does SCILLC assume any liability arising out of the application or use of any product or circuit and2. Should the duration exceeds 50 ms the power supply would protect itself and enter hiccup mode www BDTt com ON NCP1255PRNGEVB Mee Vin 100 V rms Normal 124 Thase na D eclench api Edge Positive 1 00 sid 100 kS 10 kS s errs D clench ae 500 ms div Norm 100 KS 20 kS s Edge Positive Figure 4 The Double Hiccup Nicely Limits the Input Average Power while in Burst Conclusion This evaluation board user s manual shows the peak power capability offered by the NCP1255 and the overall good efficiency brought by the frequency foldback technique The frequency excursion offers a nice means of 2 C3 Fula 0 1 00 Vidiv __2 0 m ofst 2 000 ofst C2 Dm 500 m idiv 1 00 Widi 5 0 m ofst 2000 ofst VeB t Moase OmaBD 50 0 ms div Auto Peery Vv 100 ks 200 kS s Edge Positive VFB t sf D clenc ier Gia 50 0 msidiv Auto 2 53 V 100kS 200kS s Edge Positive Figure 5 By Increasing the Switching Frequency Up to 130 kHz the Controller Authorizes Peak Power for a Certain Amount of Time transiently increasing the power capability without affecting the transformer as the peak current remains constant Packed with a wealth of features this SOIC package will let you build safe and rugged power converters with a limited count of surrounding components nt 9 on 2mi com 4 NCP1255PRNGEVB Table 2 BILL OF MATERIAL FOR THE NCP1255 EVALUATION BOARD Description Value Commen
3. NCP1255PRNGEVB LA JU ZZ 35A OL YLO LLH LEVdION MSO en OSL e qz ivz edhL A OSZ ld LO6ZNZ b 5A OEE XE 4 OSE XE MX b 4d oor Sahat 89 35A SLL VWSL9 H4AS dAjZO8MNZd LS ven LO Z0 8 0 7 L LNH J3UYLeyYIS HW Ze xg a o9 LANN Ld V OW co vla OJ 06 OJ 068 oct 907Na YOI 8 LZ O SHNW Ace za occJA9d 9q 4d 089 308 LLO SLY Figure 1 The Typical Implementation of the NCP1255 in an Isolated Flyback Converter Authorizing Peak Power Excursions www B D FT com ON Cc NCP1255PRNGEVB The Specifications The evaluation board must deliver 32 V at a nominal 25 W output power lout 0 8 A When the frequency increases to 130 kHz the peak power is up to 35 W or a 40 increase compared to the nominal value The duration of the peak is set by resistance R7 pulling pin 8 down to ground When set to 200 ms toyz as in this board the short circuit duration tsc is internally limited to 50 ms tsc tov 4 Should the output current further grow as the frequency is clamped the feedback voltage rises up to its open loop value 4 5 V In this mode the delivered power increases to 41 W or a 64 peak compared to the 25 W nominal value The complete power supply specifications are as follows Voit 32 V Vin 100 240 V rms Tout nom 0 8 A Continuous Delivery of 25 W Tout peak 1 3 A Peak Power of 41 W Few nom 65 kHz Few max 130 kHz Th
4. TO220 STP7NK80ZFP MOSFET Nicos eres Q2 PNP PMBT2907A SOT23 PMBT2907A Transistor L1 1 Self ene 0 8 02 ieee hole ne ee 0 8 02 2x27 MH J2 1 PCB Daaa Daad hole Baill ew Terminal Block pm e ere SFCBS M4 a Through hole a ee M4 16M 01 16M 01 This is a Pb free device www BD Tt tom ON NCP1255PRNGEVB TRANSFORMER SPECIFICATIONS CUSTOMER TERMINAL RoHS LEAD Pb FREE Sn96 Ag4 Yes Yes PART MUST INSERT FULLY TO SURFACE A IN RECOMMENDED GRID 028 12 70 147 172 alas DOT LOCATES TERM 1 3 75 4 38 1 154 MAX 1 195 MAX 29 30 gi 30 35 r fe _ NS IE rs O E as te s 1 150 MAX Mi 29 20 wi E i OL LO T e WS LOT CODE amp DATE CODE TERM NO s FOR REF ONLY 6 045 12 996 1 15 IN 25 30 PRI N 120 375V 3 748 65kHz e i y SEC e 32V 1 3A 150 4 3 80 11 12 p 299 2 ra P3 e 7 60 L 4 AUX RECOMMENDED Terminals 7 8 and 11 12 to be tied on pcb Pie PATTERN COMPONENT SIDE ELECTRICAL SPECIFICATIONS 25 C unless otherwise noted D C RESISTANCE 20 C 1 6 0 700 Ohms 10 2 5 0 160 Ohms 10 7 11 7 8 11 12 0 130 Ohms max
5. 0Y5PH63L2R Components Coe 1 emo azure ae rea moone oeno ves Cos 1 cater oe vom ves ark S roa ves D1 1 Ultra fast MUR160 Axial ON Semiconductor MUR160RLG Yes Diode b2 i L O gt Jw a 1 MURD530 DPAK 4 ON Semiconductor www BD Tt tom ON Substi Manufacturer tution Part Number Allowed lt 6 R17 R18 R19 R20 4 R2 C1 2 Q 3 4 O af 5 C5a C6 C NCP1255PRNGEVB Table 2 BILL OF MATERIAL FOR THE NCP1255 EVALUATION BOARD continued Substi Manufacturer tution ca Description Value Tolerance Part Number Allowed Comments Rectifier 1 1N4937 O Axial ON Semiconductor Semiconductor 1N4937RLG _ a 1 ao 48 a EA FDLL4148 Semiconducotr Zener Diode Diode O N93 SMDSOD80 NTE NTE Electronics O N93 O 33 V 33V Zener ME 5 anno O KE220A Semiconducotr 1 Socket PCB TR5 TE5 Radial Wickmann 5590000000 forUse Fuse 2 A 250 V T Radial Schurter 0034 6618 1 Note 1 PWM NCP1255 SOIC8 ON Semiconductor Controller Note 1 Optocoupler SF615A 2 Vishay SFH615A 4 Semiconductor Note 1 Shunt NCP431 NCP431ACSNT1G Regulator Diode KBU4K Through hole Multicomp KBU4K Bridge Through hole Wirth Electronic 750313495 PQ2625 Midcom C S SOT 23 are Line Input C8 SNAP IN 2P Through hole Schurter 4300 0099 Connector J2 Output Through hole Taiwan KBU406 Voltage Semiconductor Connector 1 HV STP7NK80ZFP
6. NCP1255GEVB NCP1255 25 W Evaluation Board User s Manual The NCP1255 features several novelties compared to the NCP1250 previously released The key feature of this component lies in its ability to push the switching frequency as the converter experiences a sudden power increase However this available extra power delivery can only be maintained for a certain amount of time Beyond this duration the controller gives up and enters an auto recovery mode This mode is perfectly suited for converters supplying highly variable loads such as Haswell based notebook adapters or inkjet printers to cite a few possible examples General Description The part is encapsulated in a SOIC 8 package but a reduced feature set version no brown out and timers are internally set the NCP1254 also exists in a tiny TSOP 6 package Featuring a low power BiCMOS process the die accepts to work with Vcc levels up to 35 V safely clamping the drive voltage below 12 V With its 15 uA start up current a high value resistive network can be used in offline applications to crank the converter naturally minimizing the wasted power in high line conditions In nominal load operations the switching frequency of this peak current mode control circuit is 65 kHz When the power demand goes up the controller increases the peak current setpoint until it reaches the upper limit 0 8 V over Rgense nO opp At this point the output power demand increase can only be answe
7. e radiated noise Besides its excellent performance in standby the TVS approach helps to maintain a safe clamping level given the wide output power excursion The chip supply is brought in via pin 6 Please note that the Start up resistances besides cranking the controller also perform the X2 discharge function for free Upon start up for a voltage less than 18 V typical the internal consumption is limited to 15 uA maximum It suddenly changes to a few mA as the controller starts to drive the 800 V MOSFET at 130 kHz when Vcc reaches 18 V The auxiliary voltage can go down to around 9 V before the controller safely stops the switching pulses The first Vcc capacitor C3 must be sized so that the auxiliary winding takes over before the UVLO is touched The auxiliary winding is tailored to deliver an auxiliary voltage above 12 V and it drops to 10 V in no load conditions This guarantees a good no load standby power performance as you will read below A low valued resistance R13 limits the voltage excursion on this auxiliary voltage in short circuit situations Regulation is ensured by pulling down the dedicated pin via an optocoupler driven from the secondary side by a NCP431 This new device does not require a 1 mA bias current as it was the case with the classical TL431 The absence of this bias current greatly contributes to reducing the no load standby power oro EW DL TTC COM ON Fence December 2012 Rev EVBUM2160 D
8. e transformer is built on a PQ26 25 type of core and features the following characteristics Primary Inductance Lp 1 mH Maximum Primary Peak Current at Ta 70 C 1 3 A Turns Ratio Np Ns 1 0 39 Turns Ratio Np Naux 1 0 19 Continuous Primary rms Current 0 8 A Continuous Secondary rms Current 1 9 A IEC 950 Safety Compliant Electrical Performance Some efficiency tests were carried on this board The current was set to its nominal value 0 8 A and reduced in a 20 step sequence Efficiency was recorded at every step and collected in Figure 2 graph As you can see the nominal efficiency is slightly less than 90 at nominal and maintains above 85 as the output power drops The average efficiency at a 100 V input is 88 3 and drops slightly less than 85 at high line 230 V rms Please note that these measurements include a 1 5 m long dc cable The light and no load numbers are as follows Table 1 LIGHT AND NO LOAD NUMBERS Low Line 100 V rms High Line 230 V rms Pout 0 W Pin 48 7 mW Pout O W Pin 100 mW Pout 0 5 W Pin 0 690 W Pout 0 5 W Pin 0 81 W Pout 0 6 W Pin 0 797 W Pout 0 6 W Pin 0 92 W Pout 0 7 W Pin 0 915 W Pout 0 7 W Pin 1 06 W These numbers are very good furthermore if we consider a low voltage IC externally cranked by a resistive network The brown out sensing network is another burden that significantly impacts the performance as well When the start up X2 net
9. ght laws and is not for resale in any manner PUBLICATION ORDERING INFORMATION LITERATURE FULFILLMENT N American Technical Support 800 282 9855 Toll Free ON Semiconductor Website www onsemi com Literature Distribution Center for ON Semiconductor USA Canada P O Box 5163 Denver Colorado 80217 USA Europe Middle East and Africa Technical Support Order Literature http www onsemi com orderlit Phone 303 675 2175 or 800 344 3860 Toll Free USA Canada Phone 421 33 790 2910 f Fax 303 675 2176 or 800 344 3867 Toll Free USA Canada Japan Customer Focus Center For additional information please contact your local Email orderlit onsemi com Phone 81 3 5817 1050 Sales Representative www BDTIC com ON gt
10. red by further shifting the switching frequency up until it reaches another limit 130 kHz The maximum power is thus obtained at this moment On the contrary in light load operations the part linearly reduces its switching frequency down to 26 kHz and enters skip cycle as power goes further down This mode of operation favors higher efficiency from high to moderate output levels and ensures the lowest acoustic noise in the transformer To improve the EMI signature a low frequency modulation brings some dither to the switching pattern Unlike other circuits the dither is kept in foldback and peak excursion modes continuously smoothing the noise signature The part hosts several new protection means such as an auto recovery brown out circuit It is adjustable via a ON Semiconductor http onsemi com EVAL BOARD USER S MANUAL resistive divider A double hiccup on the Vcc brings down the average input power while in auto recovery fault mode Board Description The application schematic that appears in Figure 1 has been optimized to limit the leakage inductance losses and maximize the efficiency For this purpose the RDC clamping network has been replaced by a TVS based circuitry leaving enough swing to the 800 V MOSFET Again a 600 V type could have been used but would have hampered the drain voltage dynamics at turn off A capacitor in parallel with the TVS limits its peak current at the switch opening and helps softening th
11. specifically disclaims any and all liability including without limitation special consequential or incidental damages Typical parameters which may be provided in SCILLC data sheets and or specifications can and do vary in different applications and actual performance may vary over time All operating parameters including Typicals must be validated for each customer application by customer s technical experts SCILLC does not convey any license under its patent rights nor the rights of others SCILLC products are not designed intended or authorized for use as components in systems intended for surgical implant into the body or other applications intended to support or sustain life or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application Buyer shall indemnify and hold SCILLC and its officers employees subsidiaries affiliates and distributors harmless against all claims costs damages and expenses and reasonable attorney fees arising out of directly or indirectly any claim of personal injury or death associated with such unintended or unauthorized use even if such claim alleges that SCILLC was negligent regarding the design or manufacture of the part SCILLC is an Equal Opportunity Affirmative Action Employer This literature is subject to all applicable copyri
12. ts Resistor 2 2 kQ SMD0805 Multicomp Not Wired Resistor 1 5 Q 0 5 W SMD2510 Panasonic 0 5 W e f voos veomp wonPoswarvoorrae ve Ooo R4a R4B 2 Resistor 15 kQ 1 Through hole Vishay BC MRS25000C1503FCT00 Components R5 1 Resistor 80 6 kQ 0 1 SMD0805 TE Connectivity RP73D2A80K6BTG Yes Holsworthy R9c Yes Strapped R12 1 Resistor 0 Q 1 Through hole Vishay BC MRS25000C2209FCT00 Components R13 1 Resistor 10 Q 1 Through hole Vishay BC MRS25000C 1509FCTOO Yes Components R14 1 Resistor 2 2 MQ 1 Through hole Vishay BC MRS25000C2204FCTOO Yes 0 6 W Components a R16 330 kQ SMD0805 Multicomp MCHPO5W4F3303T5E Yes o 118 kQ SMD0805 Multicomp MCTC0525B1183T5E ys fo Resistor 80 6 kQ 1 Through hole Vishay BC MRS25000C8069FCTOO Yes 0 6 W Components Resistor 820 kQ 1 Through hole Vishay BC MRS25000C8203FCT0OO Yes 0 6 W Components Resistor 390 kQ 1 Through hole Vishay BC MRS25000C3903FCTOO Yes 0 6 W Components Resistor 330 kQ SMD0805 Multicomp MCHPOSW4F3303T5E EN Capacitor 33 nF 250 V Through hole Vishay MKT 1822 333 405 Ys o Electrolytic 680 uF 35 V Through hole Rubycon 35ZL680MEFC12 5X20 i Capacitor Capacitor 470 pF Muticomp ve Electrolytic 1 uF 16 V 20 Radial Murata MURGRM31MR71C105K Yes Capacitor AO1L Electrolytic 100 uF 400 V 20 Through hole Nichicon UCY2G101MHD Yes Capacitor ve 7 C8 100 pF 1 kV Through hole F101K25S3NN63J5R C11 Capacitor 680 pF 100 V 10 Through hole Vishay BC D681K2
13. work and the brown out divider are removed while the converter delivers an unloaded 32 V output the input consumption is measured at 50 mW with a 230 V rms input voltage 95 90 Vin 100 V rms 85 80 Vin 230 V rms n 15 70 65 60 0 5 10 15 20 25 30 Pout W Figure 2 The Efficiency is Maintained in Light load Conditions Thanks to the Frequency Foldback Technique Typical Waveforms Some typical signals have been captured on the operating board The start up sequence at a 100 V rms input is clean exempt from output overshoot Figure 3 Vin 100 V rms x v Thase 0 00 sfDeclench xa 10 0 Vidiv 5 00 Vidi 500 msidiv Arr ter 79V 100 mv ofst 0 00 offset 100 kS 20 kS s Edge Positive Figure 3 There is No Noticeable Output Voltage Overshoot Upon Start Up at Low Line In short circuit the double hiccup Figure 4 nicely reduces the duty cycle in burst mode to less than 3 This greatly helps to reduce the average input power while in fault mode The peak power behavior was also tested as shown in Figure 5 In the left side the peak power is 35 W and lasts 100 ms The feedback voltage is around 4 V the controller considers an overload transient The output voltage drop is well contained in the allowable limits 5 If the transient load duration is reduced to slightly below 50 ms but the power increased to 41 W the controller lets the voltage drop while authorizing the peak excursion
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