? semiconductor components industries, llc, 2005 may , 2005 ? rev . 0 1 publication order number: and8209/d and8209/d 90 w , single stage, notebook adaptor prepared by: t erry allinder on semiconductor sr . applications engineer general description the 90 w demo board demonstrates the wide range of features found in the ncp1651. it provides an 18.5 v , 4.86 a isolated output, foldback current limit which is ideal for low?cost battery char ger and notebook adaptor applications. this unit will provide an isolated 18.5 v output from an input source with a frequency range from 47 hz to 63 hz, and a voltage range of 90 v rms to 265 v rms . it is fully self?contained and includes an internal high voltage startup circuit, and bias supply that operates of f of the flyback transformer auxiliary winding. i n addition to excellent power factor , this chip of fers fixed frequency operation in continuous and discontinuous modes of operation. it has a wide variety of protection features, including instantaneous current limiting, average current limiting, and an accurate secondary side power limit. features ? fixed frequency operation ? operation over the universal input range ? multiple protection schemes ? single power stage with isolated output ? startup and bias circuits included t able 1. demonstration board specifications requirements symbol min max input vac 90 265 frequency hz 47 63 vo (static regulation) vdc 18.4 18.6 io adc 0 4.86 output power w ? 90 efficiency % 84 ? standby power vin 230 vac mw ? 500 detailed circuit description t h e detailed operational description and design equations are contained in the ncp1651 data sheet and in application note and8124/d. this application note relates to this 18.5 vdc 90 w adaptor design. the 18.5 vdc 90 w adaptor was designed using the excel design spreadsheet which can be downloaded from the on semiconductor website (www .onsemi.com). the design steps for the adaptor are listed below . the schematic for the 90 w demo board, figure 7, is located at the end of the technical write up. design steps 1. specifications, refer to t able 1 (90?265 v , 18.5 v out, 90 w). 2. determine primary inductance. 3. determine turns ratio. 4. select the mosfet . 5. select the output rectifier . 6. build transformer with the lowest leakage inductance. 7. select the output capacitor for ripple and transient response. 8. complete control circuit design. 9. build and test! figure 1 shows a sample of the system input parameters from the ncp1651 design excel spreadsheet. in the alimitso column you enter your system requirements. below this is a column labeled aevaluationo. this is where you would like to evaluate your design. normally this is done at full load and with the minimum input ac line voltage. t o the right you have the spreadsheet plot with the average input current with respect to phase angle. application note http://onsemi.com http://
and8209/d http://onsemi.com 2 1.8 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 180 135 90 45 0 current (a) phase angle ( ) a verage current vs. phase angle limits info should not change for a given design. evaluation data may be changed as desired for various line and load conditions. limits po max = 90 w vi n max = 265 v rm s vi n min = 90 v rm s v o = 18.5 v lp = 600 h f switch = 100 khz np/ns = 8.43 peek switch voltage is approximately (v). 560.7 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 180 135 90 45 0 current (a) phase angle ( ) switching current vs. phase angle peak current pedestal current evaluation pout = 90 w v i = 90 v ef fic = 0.85 f line = 60 hz t = 10 s p in = 106 w figure 1. primary inductance selections t o determine the required primary inductance you must first determine if you want to operate in the continuous or discontinuous mode. ? ccm operation ? lower peak and rms currents ? smaller input filter ? requires higher primary inductance (more turns) ? dcm operation ? higher peak and rms currents ? lar ger input filter ? smaller inductor size for most applications on semiconductor recommends ccm operation at low line and full load to minimize losses (deciding on the boundary conditioned from ccm to dcm depending on your magnetics size trade?of fs). using the design spreadsheet we selected a primary inductance of 600 h . using 600 h the input current is ccm at low line and full load, and starts to go discontinuous at 230 v ac near the zero crossing of the line. selecting this operating mode allows for a lower t otal harmonic distortion (thd) and a high power factor (pf), and lower peak current. a lower primary inductance can be used to reduce the size of the flyback transformer , understanding that it will result in a higher thd, lower pf , and higher peak current which results in higher losses. refer to the section labeled ademo board test resulto for final demo board performance.
and8209/d http://onsemi.com 3 t ransformer t urns ratio there are several tradeof fs that must be considered when selecting the transformer turns r a t i o (n). the first is the peak primary current, the second is the maximum voltage stress on the flyback mosfet (for more details refer to application note and8124/d), and the third is the output diode reverse voltage. figure 2 graphical shows the relationships, on the left axis is the mosfet drain to source voltage (vds). the horizontal axis is the transformer turns ratio, and the right vertical axis is the output diode reverse voltage. for an 18.5 vdc output the graph shows that the transformer turns ratio can be between 4.6 and 9.4 (operating from the universal ac input). the mosfet in our design has a vds rating of 800 v , this is the peak voltage across the device at turn?of f (excluding the leakage inductance spike) is: vds = v inmax 1.414 + (v o + vf) n where: v inmax = 265 v ac v o = 18.5 vdc t o provide some mar gin for the leakage inductance spike, the design goal is to keep vds below 550 v . based on the above design goals and the requirement to keep the peak current as low as possible, our turns ratio was selected to be 8.4. this will limit the mosfet vds to approximately 525 v (excluding the turn?of f leakage inductance spike), and the output diode reverse voltage to approximately 55 v . 0 100 200 300 400 500 600 700 2 345 678 9 1 0 1 1 1 2 0 50 100 150 200 250 v ds , power switch drain t o source vol t age (v) max recommended mosfet v ds max recommended diode v r area of operation v r , output diode reverse vol t age (v) transformer turns ra tio figure 2. t urns ratio t radeoff t ransformer t urns ration summary ? higher n leads to lower iprim, vsec ? lower n allows lower vds, lower leakage inductance, and capacitor ripple current mosfet selection for our application one of the primary concerns is the system e f ficiency . t o reduce the conduction losses two low rdson infineon sp a1 1n80c mosfet s were used. in addition to reduce the switching loses the oscillator frequency o f the ncp1651 controller is set to run at 70 khz. output diode selection for this application we selected an on semiconductor mbr20100ct schottky diode. the mbr20100ct diode has a peak inverse voltage rating of 100 v and an average forward current rating of 10 a. leakage inductance t o minimize the ef fect of the leakage inductance spike, the coupling between the primary and secondary of the transformer needs to be as high as possible. this can be accomplished, if your transformer requires a primary with multiple layers, by interleaving the primary secondary windings. in our 18.5 vdc application, the transformer primary has fifty?nine turns, and the secondary has seven turns. the manufacturer of the transformer , tdk, wound one layer of the primary with thirty turns and then the seven turn secondary (two seven turns secondary in parallel), and the remaining twenty?nine turns of the primary . the results were a leakage inductance of approximately 8.5 h. refer to application note and8147/d where a comparison of transformer winding techniques versus leakage inductance was preformed. output v oltage ripple the output voltage ripple ( v) on the secondary of the transformer has two components, the traditional high frequency ripple associated with a flyback converter , and the low frequency ripple associated with the line frequency (50 or 60 hz). v vcap 2 vesr 2 the high frequency ripple can be calculated by: vcap ioavg dt co ioav g ipk iped 2 vesr ipk esr if we divided the output ripple into 10 increments over one cycle (180 ) the sinusoidal ripple voltage with respect to phase angle is: the low frequency ripple can be calculated by: v po 2c o v o 2 f line sin where: ipk = peak current (secondary) iped = pedestal of the secondary current co = output capacitance esr = output capacitor equivalent series resistance t = switching frequency
and8209/d http://onsemi.com 4 using the ncp1651 excel design spreadsheet the output voltage ripple is plotted versus phase angle in figure 3 and is approximately 800 mv pkpk with an output capacitance of 15,600 f. 0.50 180 135 90 45 0 ripple (v) output ripple envelope 0.40 0.30 0.20 0.10 0.00 ?0.10 ?0.20 ?0.30 ?0.40 ?0.50 degrees figure 3. excel spreadsheet output v oltage ripple for a comparison, figure 4 shows the measured output voltage ripple from the ncp1651 demo board. the results show that the excel design spreadsheets provide very accurate results. figure 4. measured output v oltage ripple control loop the control loop is set up to limit the loop bandwidth at high line (230 v ac) to approximately 15 hz with a minimum phase mar gin of 45 . the simplest way do this is with the excel design spreadsheet. in our application the final components selected were based on cost and standard components values. the loop crosses 0 db at 12 hz at high line with a phase mar gin of 50 (refer to figures 5 and 6). step 5, the aerror amplifier loop designo, below , is a captured screen from the excel design spreadsheet. the spreadsheet will recommend the compensation values to provide a stable control loop, but the user typically should select the closest standard value. for this application, the 18.5 vdc demo board, the spreadsheet recommended values were not used so we could reduce the loop bandwidth to provide a higher power factor and lower distortion. step 5 ? error amplifier loop design ncp1651 design spreadsheet provided by on semiconductor loop stability suggested v alue ctr opto = 2.5 optocoupler current t ransfer ratio (i coll /i diode ) v cc = 12 v bias v oltage for secondary operational amplifier r opto = 8,333 4,700 optocoupler series resistor r fb = 455 560 v olt error amp stability (suggested value for 10 hz crossover) c fb = 70.6 22 f v olt error amp stability (see bode plots for c fb and r fb ) f z error amp = 12.92 hz f p output = 2.68 hz
and8209/d http://onsemi.com 5 100 0.01 gain (db) open loop gain 80 60 40 20 0 ?20 ?40 ?60 figure 5. loop gain 0.1 1 10 100 1000 frequency (hz) high line low line loop phase figure 6. phase margin ?75 ?90 ?105 ?120 ?135 ?150 ?165 ?180 0.01 0.1 1 10 100 1000 phase ( ) frequency (hz)
and8209/d http://onsemi.com 6 input j1 2 1 f1 12 c29 0.47 f 1 24 3 c26 0.47 f d3 1n4006 d2 1n4006 d1 1n4006 d4 1n4006 0 c27 1.2 f d7 1n4006 c16 2.2 f r5 100 k r34 100 k r35 100 k c25 0.01 f 6 3 6 6 6 5 11 10 14 15 7 d5 mur20100ct c21 2200 f c22 3900 f c23 3900 f 0 c31 3900 f c1 3900 f r20 2 k output r21 8.2 k u4 sfh6155aa 2 1 vfb 4 3 c5 470 pf 1 2 j2 +vccsec c2 1 nf c20 1 f f mc3303 ? + f 11 2 d13 az23ck18 d8 bas19l t1 4 u38 7 5 6 c17 22 f r22 560 c24 0.01 f r23 2.67 k f d1 1 bas19lt1 r26 3.3 k r27 7.5 k c28 1 f c19 0.01 f tl431 u2 r28 3.3 k c18 0.22 f r29 2 k mc3303 ? + +vccsec u3d 14 11 f 12 13 r30 100 r6 0.006 r31 0.006 d6 mur160 q1 spp11n80c3 q2 spp11n80c3 r1 2.7 d14 bas19lt1 12 v ref 1 5 out is+ ilftr c6 470 pf 6 r7 8.6 k 7 c3 470 pf 3 r4 33 k 4 2 iavg ct ramp gnd ac cmp ac ref ac in fb/sd r10 0.2 r13 0.2 c12 0.1 f c13 0.1 f vcc 13 startup 16 u1 r2 330 k 11 10 9 8 r1 1 1.0 k c1 1 12 nf c10 1 nf c8 0.02 f r8 680 vfb r3 330 k r9 6.6 k c9 0.01 f figure 7. ncp1651 applications circuit schematic l2 0 r33 17.4 k
and8209/d http://onsemi.com 7 demo board test procedure t able 2. t est equipment ac source 85?265 v ac, 47?64 hz variable electronic load digital multimeter voltec precision power analyzer 1. connect the ac source to the input terminals j1. 2. connect a variable electronic load to the output terminals j2, the pwb is marked +, for the positive output, and ? for the return. 3. set the variable electronic load to 45 w . 4. t urn on the ac source and set it to 1 15 v ac at 60 hz. 5. v erify that the ncp1651 provides 18.5 vdc to the load. 6. v ary the load and input voltage. v erify output voltage as shown in t able 3. t able 3. expected v alues for v arying input v oltages and loads vin (vac) vo (vdc) @ no load vo (vdc) @ 45 w v o (vdc) @ 90 w thd (%) pf 90 w 90 18.7 18.6 18.5 8.0 0.995 11 5 18.7 18.6 18.5 10 0.990 230 18.7 18.6 18.5 20 0.920 t able 3 shows typical values, the initial set point (18.5 vdc may vary). 7. t o verify total harmonic distortion (thd) first, shut of f the ac power supply . 8. connect the v oltec precision power analyzer as shown in figure 1. 9. t urn on the ac source to 1 15 v ac at 60 hz and set the electronic load to 90 w (only measure the thd at full load). 10. v erify the voltage and current harmonics of the circuit as shown in t able 3. 1 1 . shut of f the power ac power supply . 12. set the variable electronic load to 90 w . 13. t urn on the ac source and set it to 230 v ac at 60 hz. 14. v erify the voltage and current harmonics of the circuit as shown in t able 3. figure 8. ncp1651 test setup
and8209/d http://onsemi.com 8 ncp1651 demo board test resul ts performance da t a regulation v i n (v ac) pin (w) vo (vdc) io (adc) po (w) eff (%) 90 106.03 18.55 4.85 89.97 84.85 115 105.21 18.55 4.85 89.85 85.40 230 105.1 18.57 4.85 90.1 85.69 standby power vin (vac) pin (mw) 115 372 230 455 power factor and thd vin (vac) pf (w) thd (%) po (w) 90 0.995 8.5 90 115 0.990 9.18 90 230 0.940 19.45 90 v endor contact list vendor u.s. phone/internet on semiconductor 1?800?282?9855 www.onsemi.com/ tdk 1?847?803?6100 www.component.tdk.com/ vishay www.vishay.com/ bussman (cooper ind.) 1?888?414?2645 www.cooperet.com/ coiltronics (cooper ind.) 1?888?414?2645 www.cooperet.com/ fairchild www.fairchildsemi.com/ panasonic www.eddieray.com/panasonic/ weidmuller www.weidmuller.com/ keystone 1?800?221?5510 www.keyelco.com/ hh smith 1?888?847?6484 www.hhsmith.com/ aavid thermalloy www.aavid.com/
and8209/d http://onsemi.com 9 t able 4. ncp1651 application circuit parts list ref des description part number manufacturer c2 cap, ceramic, chip, 0.001 f, 25 v vj0603y102kxxet vishay c3 cap, ceramic, chip, 470 pf, 25 v vj0603y471jxxet vishay c4 cap, aluminum elec., 100 f, 35 v ekb00ba310f00 vishay c5 cap, ceramic, chip, 470 pf, 25 v vj0603y471jxxet vishay c6 cap, ceramic, chip, 470 pf, 25 v vj0603y471jxxet vishay c8 cap, ceramic, chip, 0.022 f, 25 v vj0603y223kxxet vishay c9 cap, ceramic, chip, 0.01 f, 25 v vj0603y103kxxet vishay c11 cap, ceramic, chip, 0.012 f, 25 v vj0603y123kxxet vishay c10 cap, ceramic, chip, 0.001 f, 25 v vj0603y102kxxet vishay c12, c13 cap, ceramic, chip, 0.1 f, 25 v vj0606y104kxxet vishay c16 2.2 f , alum elect, 450 v (0.394 dia x 0.492h) (0.394 dia x 0.492h) eca?2whg2r2 eka00dc122p00 panasonic (digip5873) vishay sprague (20) c17 cap, ceramic, chip, 22 f, 10 v c3225x5r0j226mt tdk c18 cap, ceramic, chip, 0.22 f, 25 v vj0603y224kxxet vishay c19 cap, ceramic, chip, 0.01 f, 25 v vj0603y103kxxet vj0603y103kxaat c20 cap, ceramic, chip, 1.0 f, 25 v c3216x7r1e105kt tdk c21 220 f, alum elect, 25 v eca1em331 panasonic c1, c22, c23, c31 cap, alum, 3900 f, 25 v 25yxh3900m16x35.5 uhe1e392mhd rubycon nichicon c24 cap, ceramic, chip, 0.01 f, 50 v vj0603y103kxaat vishay c25 cap, ceramic, 0.01 f, 1.0 kv 225261148036 vishay c27 cap, 1.2 f, 275 vac f1778?512k2kct0 vishay c26, c29 cap, polypropylene, 0.47 f, 400 vdc mkp1841?447?3000 vishay?sprague c28 cap, ceramic, chip, 1.0 f, 25 v c3216x7r1e105kt tdk d1d4 diode, rectifier, 800 v, 1.0 a 1n4006 on semiconductor d5 diode, ultrafast, 200 v, 16 a mur20100ct on semiconductor d6 diode, ultrafast, 600 v, 1.0 a mur160 on semiconductor d7 diode, rectifier, 800 v, 1.0 a 1n4006 on semiconductor d8, d1 1, d14 diode, switching, 120 v, 200 ma, sot?23 bas19lt1 on semiconductor d13 zener diode, 18 v az23c18 vishay f1 fuse, 2.0 a, 250 vac 1025td2a bussman l2 5.0 a sat, 3.0 mh inductor, common mode q4007?a coilcraft q1, q2 fet, 11 a, 800 v, 0.45 ?, n?channel spa11n80c3 infineon r1 resistor, smt1206, 2.7 crcw1206270jre4 vishey r2 resistor, axial lead, 270 k, 1/4 w cmf?55?270k00fkre vishey r3 resistor, axial lead, 270 k, 1/4 w cmf?55?270k00fkre vishey r5 resistor, 100 k, 3.0 w, 5% cfp?3104jt?00k vishay r4 resistor, smt1206, 33 k crcw120633kojnta vishey r7 resistor, smt1206, 8.66 k crcw12068661f vishey r8 resistor, smt1206, 680 crcw12066800f vishey r10 resistor, smt, 0.2, 1.0 w wsl2512 .20 1% vishey dale
and8209/d http://onsemi.com 10 t able 4. ncp1651 application circuit parts list (continued) ref des description part number manufacturer r9 resistor, axial lead, 5.4 k, 1/4 w cmf?55?5k400fkbf vishey r11 resistor, smt1206, 1.0 k crc12061k00jnta vishey r12 resistor, 100 k, 3.0 w, 5% cfp?3104jt?00k vishay r13 resistor, smt, 0.2, 1.0 w wsl2512 .20 1% vishey dale r14 resistor, smt1206, 100 crc12062k100jnta vishey r20 resistor, smt1206, 2.0 k crc12062k00jnta vishey r21 resistor, smt1206, 8.2 k crc12068k20jnta vishey r22 resistor, smt1206, 2.0 k crc12062k00jnta vishey r23 resistor, smt1206, 2.67 k, 1% crcw12062670f vishey r26 resistor, smt1206, 3.3 k crc12063k30jnta vishey r27 resistor, smt1206, 7.5 k crc12067k50jnta vishey r28 resistor, smt1206, 3.3 k crc12063k30jnta vishey r29 resistor, smt1206, 2.0 k crc12062k00jnta vishey r30 resistor, smt1206, 100, 1% crcw12061000f vishey r31 1.0 w, 0.006 resistor wsl251r006ftb vishey r6 1.0 w, 0.006 resistor wsl251r006ftb vishey r33 resistor, smt1206, 17.4 k, 1% crcw120617400f vishey r34 resistor, 100 k, 3.0 w, 5% cfp?3104jt?00k vishay r35 resistor, 100 k, 3.0 w, 5% cfp?3104jt?00k vishay t1 transformer, flyback (lp 600 h) srw42ec?u10h014 tdk u1 pfc controller ncp1651 on semiconductor u2 2.5 v programmable ref, soic tl431acd on semiconductor u3 quad op a mc3303d on semiconductor u4 optocoupler, 1:1 ctr, 4 pin sfh615aa?x007 vishay hardware ref des description part number manufacturer h1 printed circuit board h2 connector 171602 w eidmuller (digi 281?1435?nd) h3 connector 171602 w eidmuller (digi 281?1435?nd) insulator 4672 keystone h8, h9 aluminum heatsinks 4.1 x 1.0 x 0.05 manufactured on semiconductor and are registered trademarks of semiconductor components industries, llc (scillc). scillc reserves the right to mak e changes without further notice t o any products herein. scillc makes no warranty , representation or guarantee regarding the suitability of its products for an y particular purpose, nor does scillc assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability , including wi thout limitation special, consequential or incidental damages. at ypicalo parameters which may be provided in scillc data sheets and/or specifications can and do vary in dif ferent application s and actual performance may vary over time. all operating parameters, including at ypicalso must be validated for each customer application by customer 's technical experts. scillc does not convey any license under its patent rights n o r 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 sit uation 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 of ficers, employees, subsidiaries, af filiates, and distributors harmless against all claims, costs, damages, and expenses, and reasonable attorney fees arising out of, direct ly 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 copyright laws and is not for resale in any manner. publica tion ordering informa tion n. american t echnical support : 800?282?9855 t oll free usa/canada japan : on semiconductor , japan customer focus center 2?9?1 kamimeguro, meguro?ku, t okyo, japan 153?0051 phone : 81?3?5773?3850 and8209/d
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