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? semiconductor components industries, llc, 2003 july, 2003 ? rev. 9 1 publication order number: ncp1200/d ncp1200 pwm current-mode controller for low-power universal off-line supplies housed in so?8 or dip?8 package, the ncp1200 represents a major leap toward ultra?compact switch?mode power supplies. thanks to a novel concept, the circuit allows the implementation of a complete offline battery charger or a standby smps with few external components. furthermore, an integrated output short?circuit protection lets the designer build an extremely low?cost ac/dc wall adapter associated with a simplified feedback scheme. with an internal structure operating at a fixed 40 khz, 60 khz or 100 khz, the controller drives low gate?charge switching devices like an igbt or a mosfet thus requiring a very small operating power. thanks to current?mode control, the ncp1200 drastically simplifies the design of reliable and cheap offline converters with extremely low acoustic generation and inherent pulse?by?pulse control. when the current setpoint falls below a given value, e.g. the output power demand diminishes, the ic automatically enters the skip cycle mode and provides excellent efficiency at light loads. because this occurs at low peak current, no acoustic noise takes place. finally, the ic is self?supplied from the dc rail, eliminating the need of an auxiliary winding. this feature ensures operation in presence of low output voltage or shorts. features ? no auxiliary winding operation ? internal output short?circuit protection ? extremely low no?load standby power ? current?mode with skip?cycle capability ? internal leading edge blanking ? 110 ma peak current source/sink capability ? internally fixed frequency at 40 khz, 60 khz and 100 khz ? direct optocoupler connection ? built?in frequency jittering for lower emi ? spice models available for transient and ac analysis ? internal temperature shutdown typical applications ? ac/dc adapters ? offline battery chargers ? auxiliary/ancillary power supplies (usb, appliances, tvs, etc.) dip?8 p suffix case 626 1 8 1 8 so?8 d suffix case 751 18 5 3 4 (top view) adj cs hv pin connections 7 6 2 nc fb gn d drv v cc marking diagrams see detailed ordering and shipping information in the package dimensions section on page 14 of this data sheet. ordering information xxx = device code: 40, 60 or 100 y = device code: 4 for 40 6 for 60 1 for 100 a = assembly location l = wafer lot y, yy = year w, ww = work week 200dy alyw 1200pxxx awl yyww 1 8 1 8 http://onsemi.com www.datasheet.co.kr datasheet pdf - http://www..net/
ncp1200 http://onsemi.com 2 6.5 v @ 600 ma d2 1n5819 c5 10 f + c3 10 f 400 v + emi filter adj fb cs gn d c2 470 f/10 v rf 470 drv v cc nc hv 1 2 3 4 8 7 6 5 universal input m1 mtd1n60e d8 5 v1 + figure 1. typical application r sense * *please refer to the application information section pin function description pin no. pin name function description 1 adj adjust the skipping peak current this pin lets you adjust the level at which the cycle skipping process takes place 2 fb sets the peak current setpoint by connecting an optocoupler to this pin, the peak current setpoint is ad- justed accordingly to the output power demand 3 cs current sense input this pin senses the primary current and routes it to the internal compara? tor via an l.e.b 4 gnd the ic ground 5 drv driving pulses the driver's output to an external mosfet 6 v cc supplies the ic this pin is connected to an external bulk capacitor of typically 10 f 7 nc no connection this un-connected pin ensures adequate creepage distance 8 hv generates the v cc from the line connected to the high?voltage rail, this pin injects a constant current into the v cc bulk capacitor www.datasheet.co.kr datasheet pdf - http://www..net/
ncp1200 http://onsemi.com 3 - + - + - + 250 ns l.e.b. 40, 60 or 100 khz clock overload? fault duration skip cycle comparator 1 v v ref 5.2 v q flip?flop dcmax = 80% 110 ma 20 k 60 k 8 k 75.5 k 29 k 1.4 v reset q set uvlo high and low internal regulator hv current source internal v cc 4 3 2 1 current sense fb adj ground drv v cc nc hv 8 7 6 5 figure 2. internal circuit architecture maximum ratings rating symbol value units power supply voltage v cc 16 v thermal resistance junction?to?air, pdip8 version thermal resistance junction?to?air, soic version r ja r ja 100 178 c/w maximum junction temperature typical temperature shutdown t jmax - 150 140 c storage temperature range t stg -60 to +150 c esd capability, hbm model (all pins except v cc and hv) - 2.0 kv esd capability, machine model - 200 v maximum voltage on pin 8 (hv), pin 6 (v cc ) grounded - 450 v maximum voltage on pin 8 (hv), pin 6 (v cc ) decoupled to ground with 10 f - 500 v minimum operating voltage on pin 8 (hv) - 30 v www.datasheet.co.kr datasheet pdf - http://www..net/
ncp1200 http://onsemi.com 4 electrical characteristics (for typical values t j = +25 c, for min/max values t j = ?25 c to +125 c, max t j = 150 c, v cc = 11 v unless otherwise noted) rating pin symbol min typ max unit dynamic self?supply (all frequency versions, otherwise noted) v cc increasing level at which the current source turns?off 6 v ccoff 10.3 11.4 12.5 v v cc decreasing level at which the current source turns?on 6 v ccon 8.8 9.8 11 v v cc decreasing level at which the latch?off phase ends 6 v cclatch ? 6.3 ? v internal ic consumption, no output load on pin 5 6 i cc1 ? 710 880 note 1 a internal ic consumption, 1 nf output load on pin 5, f sw = 40 khz 6 i cc2 ? 1.2 1.4 note 2 ma internal ic consumption, 1 nf output load on pin 5, f sw = 60 khz 6 i cc2 ? 1.4 1.6 note 2 ma internal ic consumption, 1 nf output load on pin 5, f sw = 100 khz 6 i cc2 ? 1.9 2.2 note 2 ma internal ic consumption, latch?off phase 6 i cc3 ? 350 ? a internal current source high?voltage current source, v cc = 10 v 8 i c1 2.8 4.0 ? ma high?voltage current source, v cc = 0 8 i c2 ? 4.9 ? ma drive output output voltage rise?time @ cl = 1 nf, 10?90% of output signal 5 t r ? 67 ? ns output voltage fall?time @ cl = 1 nf, 10?90% of output signal 5 t f ? 28 ? ns source resistance (drive = 0, vgate = v cchmax ? 1 v) 5 r oh 27 40 61 sink resistance (drive = 11 v, vgate = 1 v) 5 r ol 5 12 25 current comparator (pin 5 un?loaded) input bias current @ 1 v input level on pin 3 3 i ib ? 0.02 ? a maximum internal current setpoint 3 i limit 0.8 0.9 1.0 v default internal current setpoint for skip cycle operation 3 i lskip ? 350 ? mv propagation delay from current detection to gate off state 3 t del ? 100 160 ns leading edge blanking duration 3 t leb ? 230 ? ns internal oscillator (v cc = 11 v, pin 5 loaded by 1 k ) oscillation frequency, 40 khz version ? f osc 36 42 48 khz oscillation frequency, 60 khz version ? f osc 52 61 70 khz oscillation frequency, 100 khz version ? f osc 86 103 116 khz built?in frequency jittering, f sw = 40 khz ? f jitter ? 300 ? hz/v built?in frequency jittering, f sw = 60 khz ? f jitter ? 450 ? hz/v built?in frequency jittering, f sw = 100 khz ? f jitter ? 620 ? hz/v maximum duty?cycle ? dmax 74 80 87 % feedback section (vcc = 11 v, pin 5 loaded by 1 k ) internal pull?up resistor 2 rup ? 8.0 ? k pin 3 to current setpoint division ratio ? iratio ? 4.0 ? ? skip cycle generation default skip mode level 1 vskip 1.1 1.4 1.6 v pin 1 internal output impedance 1 zout ? 25 ? k 1. max value @ t j = ?25 c. 2. max value @ t j = 25 c, please see characterization curves. www.datasheet.co.kr datasheet pdf - http://www..net/
ncp1200 http://onsemi.com 5 ?25 75 50 25 100 125 0 ?25 75 50 25 100 125 0 2.10 1.90 1.50 1.70 1.30 1.10 0.90 74 62 80 56 68 38 86 92 98 104 110 11.50 11.30 11.60 11.20 11.40 11.70 750 ?25 60 75 30 50 25 leakage ( a) 0 temperature ( c) figure 3. hv pin leakage current vs. temperature figure 4. v cc off vs. temperature v ccoff (v) 9.85 9.80 9.75 9.70 9.65 9.60 9.55 9.50 9.45 figure 5. v cc on vs. temperature temperature ( c) figure 6. i cc1 vs. temperature temperature ( c) i cc1 ( a) v ccon (v) figure 7. i cc2 vs. temperature temperature ( c) figure 8. switching frequency vs. t j temperature ( c) i cc2 (ma) f sw (khz) 650 800 700 600 850 900 100 khz temperature ( c) 10 20 40 50 100 125 11.10 0 ?25 75 50 25 100 125 0 40 khz 60 khz 100 khz 40 khz 60 khz 100 khz 40 khz 60 khz ?25 75 50 25 100 125 0 100 khz 40 khz 60 khz 50 44 ?25 75 50 25 100 125 0 100 khz 40 khz 60 khz www.datasheet.co.kr datasheet pdf - http://www..net/
ncp1200 http://onsemi.com 6 1.34 1.33 1.31 1.32 1.30 1.29 1.28 76.0 74.0 78.0 80.0 82.0 84.0 86.0 400 340 430 310 370 190 460 0.88 ?25 6.45 125 6.40 25 0 v cclatchoff (v) 6.35 temperature ( c) figure 9. v cc latchoff vs. temperature figure 10. i cc3 vs. temperature i cc3 ( a) 60 50 40 30 20 10 0 figure 11. drv source/sink resistances temperature ( c) figure 12. current sense limit vs. temperature temperature ( c) current setpoint (v) figure 13. v skip vs. temperature temperature ( c) figure 14. max duty?cycle vs. temperature temperature ( c) v skip (v) duty?max (%) 6.50 0.92 0.84 0.80 0.96 1.00 50 75 25 0 100 ?25 125 source temperature ( c) 6.20 6.25 6.30 50 75 100 50 75 25 0 100 ?25 125 50 75 25 0 100 ?25 125 50 75 25 0 100 ?25 125 280 250 220 50 75 25 0 100 ?25 125 sink www.datasheet.co.kr datasheet pdf - http://www..net/
ncp1200 http://onsemi.com 7 applications information introduction the ncp1200 implements a standard current mode architecture where the switch?off time is dictated by the peak current setpoint. this component represents the ideal candidate where low part?count is the key parameter, particularly in low?cost ac/dc adapters, auxiliary supplies etc. thanks to its high?performance high?voltage technology, the ncp1200 incorporates all the necessary components normally needed in uc384x based supplies: timing components, feedback devices, low?pass filter and self?supply. this later point emphasizes the fact that on semiconductor's ncp1200 does not need an auxiliary winding to operate: the product is naturally supplied from the high?voltage rail and delivers a v cc to the ic. this system is called the dynamic self?supply (dss). dynamic self?supply the dss principle is based on the char ge/discharge of the v cc bulk capacitor from a low level up to a higher level. we can easily describe the current source operation with a bunch of simple logical equations: power?on: if v cc < v ccoff then current source is on, no output pulses if v cc decreasing > v ccon then current source is off, output is pulsing if v cc increasing < v ccoff then current source is on, output is pulsing typical values are: v ccoff = 11.4 v, v ccon = 9.8 v to better understand the operational principle, figure 15's sketch offers the necessary light: 10.00m 30.00m 50.00m 70.00m 90.00m current source off figure 15. the charge/discharge cycle over a 10 f v cc capacitor v cc on 10.6 v avg. output pulses v ccon = 9.8 v v ccoff = 11.4 v the dss behavior actually depends on the internal ic consumption and the mosfet's gate charge, qg. if we select a mosfet like the mtd1n60e, qg equals 11 nc (max). w ith a maximum switching frequency of 48 khz (for the p40 version), the average power necessary to drive the mosfet (excluding the driver efficiency and neglecting various voltage drops) is: fsw qg v cc with fsw = maximum switching frequency qg = mosfet's gate charge v cc = v gs level applied to the gate to obtain the final driver contribution to the ic consumption, simply divide this result by v cc : idriver = fsw qg = 530 a. the total standby power consumption at no?load will therefore heavily rely on the internal ic consumption plus the above driving current (altered by the driver's efficiency). suppose that the ic is supplied from a 400 v dc line. to fully supply the integrated circuit, let's imagine the 4 ma source is on during 8 ms and off during 50 ms. the ic power contribution is therefore: 400 v . 4 ma . 0.16 = 256 mw. if for design reasons this contribution is still too high, several solutions exist to diminish it: 1. use a mosfet with lower gate charge qg 2. connect pin through a diode (1n4007 typically) to one of the mains input. the average value on pin 8 becomes 2*v mains peak . our power contribution example drops to: 160 mw. c3 4.7 f 400 v + emi filter adj fb cs gnd drv v cc nc hv 1 2 3 4 8 7 6 5 ncp1200 1n4007 dstart figure 16. a simple diode naturally reduces the average voltage on pin 8 www.datasheet.co.kr datasheet pdf - http://www..net/
ncp1200 http://onsemi.com 8 3. permanently force the v cc level above v cch with an auxiliary winding. it will automatically disconnect the internal start?up source and the ic will be fully self?supplied from this winding. again, the total power drawn from the mains will significantly decrease. make sure the auxiliary voltage never exceeds the 16 v limit. skipping cycle mode the ncp1200 automatically skips switching cycles when the output power demand drops below a given level. this is accomplished by monitoring the fb pin. in normal operation, pin 2 imposes a peak current accordingly to the load value. if the load demand decreases, the internal loop asks for less peak current. when this setpoint reaches a determined level, the ic prevents the current from decreasing further down and starts to blank the output pulses: the ic enters the so?called skip cycle mode, also named controlled burst operation. the power transfer now depends upon the width of the pulse bunches (figure 18 ). suppose we have the following component values: lp, primary inductance = 1 mh f sw , switching frequency = 48 khz ip skip = 300 ma (or 350 mv / rsense) the theoretical power transfer is therefore: 1 2 lp ip 2 fsw 2.2 w if this ic enters skip cycle mode with a bunch length of 10 ms over a recurrent period of 100 ms, then the total power transfer is: 2.2 . 0.1 = 220 mw. to better understand how this skip cycle mode takes place, a look at the operation mode versus the fb level immediately gives the necessary insight: 1.4 v 4.8 v fb normal current mode operation skip cycle operation ip min = 350 mv / r sense figure 17. feedback voltage variations 3.8 v when fb is above the skip cycle threshold (1.4 v by default), the peak current cannot exceed 1 v/rsense. when the ic enters the skip cycle mode, the peak current cannot go below vpin1 / 4 (figure 19). the user still has the flexibility to alter this 1.4 v by either shunting pin 1 to ground through a resistor or raising it through a resistor up to the desired level. figure 18. output pulses at various power levels (x = 5 s/div) p1 ncp1200 http://onsemi.com 9 power dissipation the ncp1200 is directly supplied from the dc rail through the internal dss circuitry. the current flowing through the dss is therefore the direct image of the ncp1200 current consumption. the total power dissipation can be evaluated using: (v hvdc 11 v) icc2. if we operate the device on a 250 vac rail, the maximum rectified voltage can go up to 350 vdc. as a result, the worse case dissipation occurs on the 100 khz version which will dissipate 340 . 1.8 ma@tj = ?25 c = 612 mw (however this 1.8 ma number will drop at higher operating temperatures). please note that in the above example, i cc2 is based on a 1 nf capacitor loading pin 5. as seen before, i cc2 will depend on your mosfet's q g : i cc2 = i cc1 + f sw x q g . final calculations shall thus account for the total gate?charge q g your mosfet will exhibit. a dip8 package offers a junction?to?ambient thermal resistance of r j?a 100 c/w. the maximum power dissipation can thus be computed knowing the maximum operating ambient temperature (e.g. 70 c) together with the maximum allowable junction temperature (125 c): pmax t jmax t amax r r j a = 550 mw. as we can see, we do not reach the worse consumption budget imposed by the 100 khz version. two solutions exist to cure this trouble. the first one consists in adding some copper area around the ncp1200 dip8 footprint. by adding a min?pad area of 80 mm 2 of 35 copper (1 oz.) r j?a drops to about 75 c/w which allows the use of the 100 khz version. the other solutions are: 1. add a series diode with pin 8 (as suggested in the above lines) to drop the maximum input voltage down to 222 v ((2 350)/pi) and thus dissipate less than 400 mw 2. implement a self?supply through an auxiliary winding to permanently disconnect the self?supply. so?8 package offers a worse r j?a compared to that of the dip8 package: 178 c/w. again, adding some copper area around the pcb footprint will help decrease this number: 12 mm x 12 mm to drop r j?a down to 100 c/w with 35 copper thickness (1 oz.) or 6.5 mm x 6.5 mm with 70 copper thickness (2 oz.). as one can see, we do not recommend using the so?8 package for the 100 khz version with dss active as the ic may not be able to sustain the power (except if you have the adequate place on your pcb). however, using the solution of the series diode or the self?supply through the auxiliary winding does not cause any problem with this frequency version. these options are thoroughly described in the and8023/d. overload operation in applications where the output current is purposely not controlled (e.g. wall adapters delivering raw dc level), it is interesting to implement a true short?circuit protection. a short?circuit actually forces the output voltage to be at a low level, preventing a bias current to circulate in the optocoupler led. as a result, the fb pin level is pulled up to 4.1 v, as internally imposed by the ic. the peak current setpoint goes to the maximum and the supply delivers a rather high power with all the associated effects. please note that this can also happen in case of feedback loss, e.g. a broken optocoupler. to account for this situation, the ncp1200 hosts a dedicated overload detection circuitry. once activated, this circuitry imposes to deliver pulses in a burst manner with a low duty?cycle. the system recovers when the fault condition disappears. during the start?up phase, the peak current is pushed to the maximum until the output voltage reaches its target and the feedback loop takes over. this period of time depends on normal output load conditions and the maximum peak current allowed by the system. the time?out used by this ic works with the v cc decoupling capacitor: as soon as the v cc decreases from the v ccoff level (typically 11.4 v) the device internally watches for an overload current situation. if this condition is still present when v ccon is reached, the controller stops the driving pulses, prevents the self?supply current source to restart and puts all the circuitry in standby, consuming as little as 350 a typical (i cc3 parameter). as a result, the v cc level slowly discharges toward 0. when this level crosses 6.3 v typical, the controller enters a new startup phase by turning the current source on: v cc rises toward 11.4 v and again delivers output pulses at the uvlo h crossing point. if the fault condition has been removed before uvlo l approaches, then the ic continues its normal operation. otherwise, a new fault cycle takes place. figure 20 shows the evolution of the signals in presence of a fault. www.datasheet.co.kr datasheet pdf - http://www..net/
ncp1200 http://onsemi.com 10 time internal fault flag time time drv v cc driver pulses driver pulses 11.4 v 9.8 v 6.3 v regulation occurs here latch?off phase fault is relaxed fault occurs here startup phase figure 20. if the fault is relaxed during the v cc natural fall down sequence, the ic automatically resumes. if the fault persists when v cc reached uvlo l , then the controller cuts everything off until recovery. calculating the v cc capacitor as the above section describes, the fall down sequence depends upon the v cc level: how long does it take for the v cc line to go from 11.4 v to 9.8 v? the required time depends on the start?up sequence of your system, i.e. when you first apply the power to the ic. the corresponding transient fault duration due to the output capacitor charging must be less than the time needed to discharge from 11.4 v to 9.8 v, otherwise the supply will not properly start. the test consists in either simulating or measuring in the lab how much time the system takes to reach the regulation at full load. let's suppose that this time corresponds to 6ms. therefore a v cc fall time of 10 ms could be well appropriated in order to not trigger the overload detection circuitry. if the corresponding ic consumption, including the mosfet drive, establishes at 1.5 ma, we can calculate the required capacitor using the following formula: t v c i , with v = 2v. then for a wanted t of 10 ms, c equals 8 f or 10 f for a standard value. when an overload condition occurs, the ic blocks its internal circuitry and its consumption drops to 350 a typical. this appends at v cc = 9.8 v and it remains stuck until v cc reaches 6.5 v: we are in latch?off phase. again, using the calculated 10 f and 350 a current consumption, this latch?off phase lasts: 109 ms. protecting the controller against negative spikes as with any controller built upon a cmos technology, it is the designer's duty to avoid the presence of negative spikes on sensitive pins. negative signals have the bad habit to forward bias the controller substrate and induce erratic behaviors. sometimes, the injection can be so strong that internal parasitic scrs are triggered, engendering irremediable damages to the ic if they are a low impedance path is offered between v cc and gnd. if the current sense pin is often the seat of such spurious signals, the high?voltage pin can also be the source of problems in certain circumstances. during the turn?off sequence, e.g. when the user un?plugs the power supply, the controller is still fed by its v cc capacitor and keeps activating the mosfet on and off with a peak current limited by rsense. unfortunately, if the quality coefficient q of the resonating network formed by lp and cbulk is low (e.g. the mosfet rdson + rsense are small), conditions are met to make the circuit resonate and thus negatively bias the controller. since we are talking about ms pulses, the amount of injected charge (q = i x t) immediately latches the controller which brutally discharges its v cc capacitor. if this v cc capacitor is of sufficient value, its stored energy damages the controller. figure 21 depicts a typical negative shot occurring on the hv pin where the brutal v cc discharge testifies for latch?up. www.datasheet.co.kr datasheet pdf - http://www..net/
ncp1200 http://onsemi.com 11 figure 21. a negative spike takes place on the bulk capacitor at the switch?off sequence simple and inexpensive cures exist to prevent from internal parasitic scr activation. one of them consists in inserting a resistor in series with the high?voltage pin to keep the negative current to the lowest when the bulk becomes negative (figure 22). please note that the negative spike is clamped to 2 x vf due to the diode bridge. please refer to and8069 for power dissipation calculations. another option (figure 23) consists in wiring a diode from v cc to the bulk capacitor to force v cc to reach uvlolow sooner and thus stops the switching activity before the bulk capacitor gets deeply discharged. for security reasons, two diodes can be connected in series. figure 22. a simple resistor in series avoids any latch?up in the controller cv cc d3 1n4007 8 7 6 5 1 2 3 4 + cbulk + 1 3 cv cc rbulk > 4.7 k 8 7 6 5 1 2 3 4 + cbulk + 1 2 3 figure 23. or a diode forces v cc to reach uvlolow sooner a typical application figure 24 depicts a low?cost 3.5 w ac/dc 6.5 v wall adapter. this is a typical application where the wall?pack must deliver a raw dc level to a given internally regulated apparatus: toys, calculators, cd?players etc. thanks to the inherent short?circuit protection of the ncp1200, you only need a bunch of components around the ic, keeping the final cost at an extremely low level. the transformer is available from different suppliers as detailed on the following page. www.datasheet.co.kr datasheet pdf - http://www..net/
ncp1200 http://onsemi.com 12 6.5 v @ 600 ma d3 1n5819 c9 10 f + c3 4.7 f 400 v + adj fb cs gnd c5 470 f/ 10 v r2 220 drv v cc nc hv 1 2 3 4 8 7 6 5 universal input m1 mtd1n60e ncp1200 d6 5 v1 c2 4.7 f 400 v + l6 330 h l5 330 h clamping network d clamp r clamp clamp snubber r snubber c snubber ic1 sfh615a?2 r6 2.8 + c10 4.7 f/ 10 v + t1 r7 optional networks r9 10 figure 24. a typical ac/dc wall adapter showing the reduced part count thanks to the ncp1200 l4 2.2 h t1: lp = 2.9 mh, np:ns = 1:0.08, leakage = 80 h, e16 core, ncp1200p40 to help designers during the design stage, several manufacturers propose ready?to?use transformers for the above application, but can also develop devices based on your particular specification: eldor corporation headquarter via plinio 10, 22030 orsenigo (como) italia tel.: +39?031?636 111 fax : +39?031?636 280 email: eldor@eldor.it www.eldor.it ref. 1: 2262.0058c: 3.5 w version (lp = 2.9 mh, lleak = 80 h, e16) ref. 2: 2262.0059a: 5 w version (lp = 1.6 mh, lleak = 45 h, e16) egston gesmbh grafenbergerstra e 37 3730 eggenburg austria tel.: +43 (2984) 2226?0 fax : +43 (2984) 2226?61 email: info@egston.com http://www.egston.com/english/index.htm ref. 1: f0095001: 3.5 w version (lp = 2.7 mh, lleak = 30 h, sandwich configuration, e16) atelier special de bobinage 125 cours jean jaures 38130 echirolles france tel.: 33 (0)4 76 23 02 24 fax: 33 (0)4 76 22 64 89 email: asb@wanadoo.fr ref. 1: ncp1200?10 w?um: 10 w for usb (lp = 1.8 mh, 60 khz, 1:0.1, rm8 pot core) coilcraft 1102 silver lake road cary, illinois 60013 usa tel: (847) 639?6400 fax: (847) 639?1469 email: info@coilcraft.com http://www.coilcraft.com ref. 1: y8844?a: 3.5 w version (lp = 2.9 mh, lleak = 65 h, e16) ref. 2: y8848?a: 10 w version (lp = 1.8 mh, lleak = 45 h, 1:01, e core) www.datasheet.co.kr datasheet pdf - http://www..net/
ncp1200 http://onsemi.com 13 improving the output drive capability the ncp1200 features an asymmetrical output stage used to soften the emi signature. figure 25 depicts the way the driver is internally made: v cc 2 3 1 5 7 q q\ figure 25. the higher on resistor slows down the mosfet while the lower off resistor ensures fast turn?off. 40 12 in some cases, it is possible to expand the output drive capability by adding either one or two bipolar transistors. figures 26, 27, and 28 give solutions whether you need to improve the turn?on time only, the turn?off time or both. rd is there to damp any overshoot resulting from long copper traces. it can be omitted with short connections. results showed a rise fall time improvement by 5x with standard 2n2222/2n2907: ncp1200 1 2 3 4 8 7 6 5 2n2907 2n2222 to gate rd figure 26. improving both turn?on and turn?off times ncp1200 1 2 3 4 8 7 6 5 2n2907 1n4148 to gate figure 27. improving turn?off time only 6 ncp1200 1 2 3 4 8 7 5 2n2222 to gate 1n4148 figure 28. improving turn?on time only www.datasheet.co.kr datasheet pdf - http://www..net/
ncp1200 http://onsemi.com 14 if the leakage inductance is kept low, the mtd1n60e can withstand accidental avalanche energy, e.g. during a high?voltage spike superimposed over the mains, without the help of a clamping network. if this leakage path permanently forces a drain?source voltage above the mosfet bvdss (600 v), a clamping network is mandatory and must be built around rclamp and clamp. dclamp shall react extremely fast and can be a mur160 type. to calculate the component values, the following formulas will help you: r clamp = 2 v clamp (v clamp (v out vf sec) n) l leak ip 2 fsw c clamp v clamp v ripple fsw r clamp with: v clamp : the desired clamping level, must be selected to be between 40 to 80 volts above the reflected output voltage when the supply is heavily loaded. v out + vf : the regulated output voltage level + the secondary diode voltage drop l leak : the primary leakage inductance n : the ns:np conversion ratio f sw : the switching frequency v ripple : the clamping ripple, could be around 20 v another option lies in implementing a snubber network which will damp the leakage oscillations but also provide more capacitance at the mosfet's turn?off. the peak voltage at which the leakage forces the drain is calculated by: v max ip l leak c lump where c lump represents the total parasitic capacitance seen at the mosfet opening. typical values for rsnubber and csnubber in this 4w application could respectively be 1.5 k and 47 pf. further tweaking is nevertheless necessary to tune the dissipated power versus standby power. available documents aimplementing the ncp1200 in low?cost ac/dc converterso, and8023/d aconducted emi filter design for the ncp1200'', and8032/d aramp compensation for the ncp1200'', and8029/d transient and ac models available to download at: http://onsemi.com/pub/ncp1200 ncp1200 design spreadsheet available to download at: http://onsemi.com/pub/ncp1200 ordering information device type marking package shipping ncp1200p40 f sw = 40 khz 1200p40 pdip8 50 units / rail ncp1200d40r2 f sw = 40 khz 200d4 so?8 2500 units /reel ncp1200p60 f sw = 60 khz 1200p60 pdip8 50 units / rail ncp1200d60r2 f sw = 60 khz 200d6 so?8 2500 units /reel ncp1200P100 f sw = 100 khz 1200P100 pdip8 50 units / rail ncp1200d100r2 f sw = 100 khz 200d1 so?8 2500 units / reel www.datasheet.co.kr datasheet pdf - http://www..net/
ncp1200 http://onsemi.com 15 package dimensions dip8 p suffix case 626?05 issue l notes: 1. dimension l to center of lead when formed parallel. 2. package contour optional (round or square corners). 3. dimensioning and tolerancing per ansi y14.5m, 1982. 14 5 8 f note 2 ?a? ?b? ?t? seating plane h j g d k n c l m m a m 0.13 (0.005) b m t dim min max min max inches millimeters a 9.40 10.16 0.370 0.400 b 6.10 6.60 0.240 0.260 c 3.94 4.45 0.155 0.175 d 0.38 0.51 0.015 0.020 f 1.02 1.78 0.040 0.070 g 2.54 bsc 0.100 bsc h 0.76 1.27 0.030 0.050 j 0.20 0.30 0.008 0.012 k 2.92 3.43 0.115 0.135 l 7.62 bsc 0.300 bsc m --- 10 --- 10 n 0.76 1.01 0.030 0.040 www.datasheet.co.kr datasheet pdf - http://www..net/
ncp1200 http://onsemi.com 16 package dimensions (so?8) d suffix case 751?07 issue aa seating plane 1 4 5 8 n j x 45 k notes: 1. dimensioning and tolerancing per ansi y14.5m, 1982. 2. controlling dimension: millimeter. 3. dimension a and b do not include mold protrusion. 4. maximum mold protrusion 0.15 (0.006) per side. 5. dimension d does not include dambar protrusion. allowable dambar protrusion shall be 0.127 (0.005) total in excess of the d dimension at maximum material condition. 6. 751-01 thru 751-06 are obsolete. new standaard is 751-07 a b s d h c 0.10 (0.004) dim a min max min max inches 4.80 5.00 0.189 0.197 millimeters b 3.80 4.00 0.150 0.157 c 1.35 1.75 0.053 0.069 d 0.33 0.51 0.013 0.020 g 1.27 bsc 0.050 bsc h 0.10 0.25 0.004 0.010 j 0.19 0.25 0.007 0.010 k 0.40 1.27 0.016 0.050 m 0 8 0 8 n 0.25 0.50 0.010 0.020 s 5.80 6.20 0.228 0.244 ?x? ?y? g m y m 0.25 (0.010) ?z? y m 0.25 (0.010) z s x s m on semiconductor and are registered trademarks of semiconductor components industries, llc (scillc). scillc reserves the right to mak e 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, and s pecifically disclaims any and all liability, including without limitation special, consequential or incidental damages. atypicalo 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 atypicalso 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 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 indem nify and hold scillc and its of ficers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and re asonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized u se, even if such claim alleges that scillc was negligent regarding the design or manufacture of the part. scillc is an equal opportunity/affirmative action employ er. publication ordering information japan : on semiconductor, japan customer focus center 2?9?1 kamimeguro, meguro?ku, tokyo, japan 153?0051 phone : 81?3?5773?3850 on semiconductor website : http://onsemi.com for additional information, please contact your local sales representative. ncp1200/d the product described herein (ncp1200), may be covered by the following u.s. patents: 6,385,060; 6,587,357. there may be other patents pending. literature fulfillment : literature distribution center for on semiconductor p.o. box 5163, denver, colorado 80217 usa phone : 303?675?2175 or 800?344?3860 toll free usa/canada fax : 303?675?2176 or 800?344?3867 toll free usa/canada email : orderlit@onsemi.com n. american technical support : 800?282?9855 toll free usa/canada www.datasheet.co.kr datasheet pdf - http://www..net/

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