EVBUM2147 - NCP1351 57 W Adapter Evaluation Board User's
Contents
1. R6b R6a R10 R11 R13 R12 Qty 3 4 4 2 4 4 4 i 1 mb 1 1 4 2 4 mb mb 2 2 4 hk 2 Description SMD capacitor Capacitor electrolytic capacitor electrolytic capacitor Capacitor electrolytic capacitor SMD capacitor SMD capacitor X2 capacitor electrolytic capacitor Y1 capacitor SMD capacitor SMD capacitor electrolytic capacitor SMD capacitor zener diode ultrafast rectifier hight speed diode schottky diode hight speed diode hight speed diode heatsink shunt regulator diode bridge connector connector Common mode nductor power MOSFET N Channel PNP transistor SMD resistor resistor SMD resistor SMD resistor resistor SMD resistor SMD resistor resistor SMD resistor Value 100 nF 50 V 10 nF 630 V 4 7 uF 50 V 1000 uF 35 V 100 nF 50 V 220 uF 25 V 220 pF 50 V 220 nF 50 V 220 nF 630 V 100 uF 400 V 2 2 nF 250 V 47 pF 50 V 22 pF 50 V 100 uF 35 V 270 pF 50 V 15 V 225 mW 1 A 600 V 1 A 600 V 20 A 100 V 0 2 A 75 V 0 2 A 100 V 6 2 C W 2 5 36 V 1 100 mA 4 A 800 V 230 Vac 2 2 27 mH 0 8 A 2 2 uH 10 A 4 A 600 V 100 mA 45 V 2 2 kQ 0 25 W 1 MQ 0 33 W 2 5 kQ 0 25 W 1941 W 1 kQ 0 4 W 10 kQ2 0 25 W 39 kQ 0 25 W 47 kQ 2 W 27 kQ 0 25 W Toler ance 5 SMD 1206 PHYCOMP 10 radial Vishay 20 radial Panasonic 20 radial Panasonic 10 radial 20 radial Panasonic 5 SMD 1206 P2. S g y yes yes yes yes yes yes S p y yes yes yes e lt 0 3 yes S lt MD yes yes yes yes yes yes yes yes yes Free r D pa a yes yes yes yes es yes yes yes yes yes yes yes es yes yes yes yes yes yes yes yes yes yes yes yes yes yes es yes yes yes yes yes yes yes yes yes yes NCP1351ADAPGEVB BILL OF MATERIALS FOR THE NCP1351ADAPGEVB SMD resistor 4 15 8 9 0 GMOS IC NCP19518 Toler Manufacturer Part Description Value ance Number FIX 4 H LCBS TF M4 8 01 pf soe ON Semiconductor NCP1351B Substi tution Lead Allowed Free Welwyn pa a pe Pre NOTE Screws nuts and washers attached to heatsinks MUST be non conductive Nylon TEST PROCEDURE FOR THE NCP1351 ADAPTER EVALUATION BOARD NOTE Be careful when manipulating the boards in operation lethal voltages up to 400 V are present on the primary side An isolation transformer is also recommended for safer manipulations Necessary Equipment e 1 Current limited 90 265 Vrms AC source current limited to avoid board destruction in case of a defective part or a 380 VDC source AGILENT 6811 e 1 AC Volt Meter able to measure up to 300 V AC KEITHLEY 2000 e 1 AC Amp Meter able to measure up to 3 A AC KEITHLEY 2000 e 1 DC Volt Meter able to measure up to 20 V DC KEITHLEY 2000 AC Source 90 265 Va
3. HYCOMP SMD 1206 10 20 radial Evox Rifa 20 radial Panasonic 20 radial Ceramite 5 SMD 1206 PHYCOMP 5 SMD 1206 PHYCOMP 20 radial Panasonic 5 SMD 0805 PHYCOMP 5 SOT23 ON Semiconductor 0 axial ON Semiconductor 0 axial ON Semiconductor 0 TO220 ON Semiconductor 0 axial Philips Semiconductor 0 SOD 123 ON Semiconductor 0 radial Seifert 2 TO92 ON Semiconductor 0 radial Multicomp 0 radial Schurter 0 rad5 08mm Weidmuller 0 radial Schaffner 0 radial Wurth Elektronik 0 TO220 Infineon 0 TO92 ON Semiconductor 1 SOT23 Welwyn 5 Vishay 2 SMD 1206 Welwyn 5 SMD 2512 PHYCOMP 5 Vishay 2 SMD 1206 Welwyn 2 SMD 1206 Welwyn 5 Multicomp 2 SMD 1206 Welwyn a a http onsemi com 8 Manufacturer Part Number 2238 581 15649 2222 372 61103 ECA1HM4R7 EEUFC1V102 SR215C104KTR EEUFC1E221 2238 863 15471 CM316X7R224K50AT PHE840MD6220M ECA2GM101 440LD22 2238 863 15479 2238 863 15229 ECA1VM101 2238 861 15271 BZX84C15LT1G MUR160G 1N4937G MBR20100CTG 1N4148 MMSD4148G KL195 25 4 SWI TL431ILPG KBU4K 0721 PP PM5 08 2 90 RN114 0 8 02 744772022 SPP04N60C3 BC857 WCR12062K22 SFR2500001004JR50 WCR12062K52 232276260108 SFR2500001001JR50 WCR120610K2 WCR120639K2 MCF2W47K WCR120627K2 Substi tution Allowed yes yes yes afe E yes yes yes yes yes yes yes yes o yes yes yes yes
4. NCP1351ADAPGEVB NCP1351 57 W Adapter Evaluation Board User s Manual The NCP1351 at a Glance Fixed ton variable tore current mode control implementing a fixed peak current mode control hence the more appropriate term quasi fixed ton the NCP1351 modulates the off time duration according to the output power demand In high power conditions the switching frequency increases until a maximum is hit This upper limit depends on an external capacitor selected by the designer In light load conditions the off time expands and the NCP1351 operates at a lower frequency As the frequency reduces the contribution of all frequency dependent losses accordingly goes down driver current drain capacitive losses switching losses naturally improving the efficiency at various load levels Peak Current Compression at Light Loads Reducing the frequency will certainly force the converter to operate into the audible region To prevent the transformer mechanical resonance the NCP1351 gradually reduces compresses the peak current setpoint as the load becomes lighter When the current reaches 30 of the nominal value the compression stops and the off duration keeps expanding towards low frequencies Low Standby power the frequency reduction technique offers an excellent solution for designers looking for low standby power converters Also compared to the skip cycle method the smooth off time expansion does not bring additional rip
5. ative Action Employer This literature is subject to all applicable copyright 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 Zo 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 EVBUM2147 D
6. bility arising out of the application or use of any product or circuit and 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 Affirm
7. c AC DC 19 V 3A adapter e 1 DC Amp Meter able to measure up to 5 A DC KEITHLEY 2000 e 1 DC Electronic Load 0 4 A AGILENT 6060B Test Procedure 1 Apply 90 230 V AC over the Vin pins Output pins Vout Ground are left floating 2 Measure the output voltage between pins Vout et Ground with a volt meter on the auto range The measurement should be between 18 8 and 19 2 V 3 Connect the electronic load between pin Vout et Ground Verify that the output voltage stays above 19 V Set current 3 A 4 If every step is going well the board 1s considered to be ok DC LOAD 19VW 0 3A Figure 15 Test Setup http onsemi com 9 NCP1351ADAPGEVB PCB layout NCP1351ZADIG D TLS 0406 SIG VZ TSETIDN JOJ3MPUOITUSS NO Figure 17 Copper Traces at jaz cll wan man TM ele ee A El TE lr Figure 18 SMD components ON Semiconductor and f 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 lia
8. itching losses The no load standby power stays below 150 mW at high line a good performance for a 60 W adapter Please note that the high voltage probe observing the drain was removed and the load totally disconnected to avoid leakage The OPP proves to work ok Perhaps an improved margin would help 500 ms div aja If oos 4J ol pe e T eje zig Figure 6 Startup time Vin 90 Vac 110 Vac 833 mW 112 mW 230 Vac 865 mW 139 mW 265 Vac 41A 230 Vac 0 58s at 90 Vac which could be obtained by slightly increasing Ryo or if necessary by increasing R45 Despite operation in the audible range we did not notice any noise problems coming from either the transformer or the RCD clamp capacitor Scope shots Below are some oscilloscope shots gathered on the demoboard oje 500 ms div Figure 7 Startup time Vin 230 Vac http onsemi com 4 NCP1351ADAPGEVB 0 Rim OEM O Him or margin oje als S00 mszdiv ajy oos KUD jessy it it oje gagal 100 ms div Figure 8 Startup Sequence to Test the Margin on Figure 9 Short circuit Vin 265 Vac the 100 ms Timer Vin 90 Vac lout 3 A On the above picture a short circuit has been made at the highest line voltage During the burst operation the input power was maintained to 6 3 W at 275 Vac It dropped to 5 2 W at 230 Vac Control Setup Measure Analyze Utilities Help 13 34 Qe DORE Figure 10 Maximum Output Power Vin 265 Vac Note the go
9. od margin on the drain thanks to the low leakage term http onsemi com 5 NCP1351ADAPGEVB Figure 11 The Drain source Waveform at Different Output Currents 3 A 2 A and 1 A The Input Voltage is 230 Vac cozes MELS ET ER Figure 12 Short circuit on the Optocoupler LED The output voltage increases to 28 V and then the controller latches off Different levels can be obtained by changing D1 http onsemi com 6 NCP1351ADAPGEVB 1 o ela El 20 0 ms div aa Dos fol 7 Py Figure 13 Load Step from 0 5 Ato 3 A with a1 A us Slew rate from a 90 Vac t 6 eja 8 20 0 ms div DR It Ajol ppc Ea i Figure 14 Load Step from 0 5 A to 3 A witha 1 A us Slew rate from a 230 Vac source Conclusion The adapter built with the NCP1351 exhibits an excellent performance on several parameters like the efficiency and the no load standby The OPP is made in a simple non dissipative way and does not hamper the standby power The limited number of surrounding components around the controller associated to useful features timer based protection latch input makes the NCP1351 an excellent choice for cost sensitive adapter designs http onsemi com 7 NCP1351ADAPGEVB BILL OF MATERIALS FOR THE NCP1351ADAPGEVB Desig nator C1 C4 C5 C9 O Q ao N C5b C5a OJ O N C10 11 C14 C15 C17 C18 O oo D8 D9 HS1 HS2 laa ed ee E TETTE AA TTT PFPA AE R2 R7 5
10. ort circuit protection Offering a good EMI signature the 65 kHz maximum switching frequency has become an industry standard for the vast majority of power supplies connected on the mains With the NCP1351 selecting a C capacitor of 270 pF fixes the upper limit to 65 kHz As a result when the controller detects a need for a higher frequency implying an overload condition it will start to charge the timer capacitor if the overload disappears the timer capacitor goes back to zero If the fault remains the timer capacitor voltage reaches 5 V and starts the auto recovery process The transformer has been derived using the design recommendations described in the NCP1351 data sheet We came up to the following values Lp 770 uH Np Ns 1 0 25 Np Naux 1 0 18 It is also possible to use the Excel spreadsheet available from the ON Semiconductor website which also gives transformer parameters The core is a PQ26x25 made of a 3F3 material and has been manufactured by Delta Electronics reference 86H 6232 The leakage inductance is kept around 1 leading to a good efficiency and reduced losses in no load conditions The schematic appears on Figure 3 The converter operates in CCM with a 40 duty cycle at low mains and stays CCM at high line Despite Publication Order Number EVBUM2147 D NCP1351ADAPGEVB the frequency variation it is possible to evaluate the input voltage point at which the converter leaves CCM ie do 2PoutVo
11. ple in no load conditions the output voltage remains quiet Natural Frequency Dithering the quasi fixed tp mode of operation improves the EMI signature since the switching frequency varies with the natural bulk ripple voltage Extremely Low Start up Current built on a proprietary circuitry the NCP1351 startup section does not consume more than 10 uA during the startup sequence The designer can thus easily combine startup time and standby consumption Overload Protection Based on Fault Timer every designer knows the pain of building converters where a precise over current limit must be obtained When the fault detection relies on the auxiliary Vcc the pain even increases Here the NCP1351 observes the lack of feedback current starts a timer to countdown At the end of its charge the timer either triggers an auto recovery sequence auto restart B version or permanently latches off A Latch Fault Input a dedicated input lets the designer externally trigger the latch to build additional protections such as over voltage OVP or over temperature OTP O Semiconductor Components Industries LLC 2012 October 2012 Rev 2 ON Semiconductor http onsemi com EVAL BOARD USER S MANUAL Figure 1 Evaluation Board Photo The Schematic The design must fulfil the following specifications Input voltage 90 265 Vac Output voltage 19 V 3 A Over voltage protection Over power protection Auto recovery sh
12. power supply output impedance and regulation will suffer A 1 5 KQ has proven to do just well without degrading the standby power D2 MUR160 MBR20100 1N4937 0 D5 86H 6232 cio iy 4A 600 V CIN LD e n pe Mi SPPoaNeocs 27 KQ AA C15 oop NCP 1351 oe 39 kQ C5 0 1 uF R18 opto_e 47 KQ U1 SFH6156 2 Figure 3 The 57 W Adapter Board Featuring the NCP1351 Controller http onsemi com 2 NCP1351ADAPGEVB The overvoltage protection uses a 15 V zener diode D1 connected to the auxiliary Voc When the voltage on this rail exceeds 15 V plus the NCP1351 5 V latch trip point total is thus 20 V the circuit latches off and immediately pulls the Vcc pin down to 6 V The reset occurs when the injected current into the Vcc pin passes below a few uA that is to say when the power supply is deconnected from the mains Vbulk Ist outlet To speed up this reset phase a connection via a diode to the half wave point will reset the circuit faster Figure 4 Please note that the half wave resistor equals the original bulk start up resistor divided by 3 14 This provides the same startup current despite the half wave signal The power dissipation is also slightly reduced by 30 roughly il Rstartup 3 14 Figure 4 Connecting the startup resistor to the mains before the diode bridge helps to speed up the NCP1351 reset time when latched To satisfy the maximum power limit we can install an Over Po
13. ut ipen lbeakVoutn 2NPout Where Ipeak is the selected peak current in the inductor Vout the output voltage n the converter efficiency Pout the delivered power N the transformer turn ratio Np Ns 1 N Since we are limited to 265 Vac we can see that the converter will always be in CCM at full power To the opposite we can also predict the power level at which the converter leaves CCM at low and high line conditions MlpeakVinVout HA eq 2 Vout NVin eq 2 Pout crit For an input voltage of 120 Vdc the converter enters DCM for an output power below 42 W When the voltage increases to 330 Vdc the power level at which CCM is excited is 55 W Two 1 MQ resistors ensure a clean start up sequence with the 4 7 uF capacitor C3 directly from the bulk capacitor Despite a small value for C3 the Vcc still maintains in no load conditions thanks to the split configuration 220 pF 47 pF 2x 19 x 0 9 2 x 0 25 x 57 35 V D1 1N4148 2 x 57 x 19 380 Vdc eq 1 bulk Figure 2 The split Vcc configuration helps to start up in a small period of time CVcc to charge alone but the addition of a second larger capacitor Cres ensures enough Vcc in standby The primary side feedback current is fixed to roughly 300 uA via R5 and an additional bias is provided for the TL431 1 mA at least must flow in the TL431 in worse case conditions full load Failure to respect this will degrade the
14. wer Protection OPP circuit Given the negative sensing technique we can use a portion of the auxiliary signal during the on time as it also swings negative However we need this compensation at high line only since standby power can be affected For this reason we have installed a small integrator made of Cjg Roo To avoid charging C g during the flyback stroke Do clamps the EFFICIENCY positive excursion and offers a stronger negative voltage during the on time Finally the clamping network maintains the drain voltage below 520 V at high line 375 Vdc which provides 85 derating for the 600 V BVdss device Measurements Once assembled the board has been operated during 15 mn at full power to allow some warm up time We used a WT210A from Yokogawa to perform all power related measurements coupled to an electronic ac source Vin Pour 110 Vac 230 Vac 20 30 40 50 60 Pout W Figure 5 Switching Frequency Fey vs Pout http onsemi com 3 NCP1351ADAPGEVB Vin Pour 0 5 Output Power 0 5 W No load Power No load Overpower Protection Level Vin Pour Overpower Start up Time Vin lout 3 A Start up Duration On the above arrays we can see the excellent efficiency at different loading conditions The first explanation is the low leakage inductance on the tested transformer below 1 of the primary inductance Also the frequency reduction in lighter load configurations helps for the sw
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