Fuji Power MOSFE Power clculi mehod Design ool Cher. Overview is necessry o check wheher he ower loss hs no exceeded he Asolue Mximum Rings for using MOSFE. Since he MOSFE loss cnno e mesured using ower meer, i is required o clcule i from drin-source volge nd drin curren D wvefo oined y using device such s n oscilloscoe. his documen rovides he mehod o clcule he MOSFE loss. n ddii, how o use he loss-clculi ssisnce ool is rovided. Cher. Clculing elecric energy [] Generlly, he elecric energy [] for eriod - s indiced in Figure cn e clculed y he inegri of volge imes curren s indiced in he following formul: V ( ) ( ) d() While, () nd V() cn e exressed s follows: V() V V V ( ) + V ( ) ( ) + (3 ) V () Figure : Volge V() nd curren () for eriod - V hus, inegre hem for he ime eriod of - o oin he following elecric energy []: 3 ) ( ) ( ) ) ( ) ( ) ( ) V + V ( ) (4 ) By using he ove formul nd rirrily sering he eriod -, you cn even oin he elecric energy [] for nliner wvefo. Cher 3. Clculing elecric energy [] from volge nd curren wvefo o clcule he ower loss from volge nd curren wvefo for he eriod, divide ino rnges where liner roximi cn e lied, s indiced in Figure. OFF ON ON ON OFF OFF D 3 4 5 Figure : Exmle of loss clculi wvefo n Figure, he curren wveform sloe chnges during MOSFE is eing urned off. herefore, o clcule he loss from wvefo of Figure, divide ino,,..., 5. n cul circuis h include rsiic ccince of MOSFE, he volge nd curren chnge exenilly during rnsii eween nd off. Becuse i is difficul o exenilly reresen volge nd curren from he oserved wvefo device such s oscilloscoe, liner roximis re used. Dec D_Power clculi mehod Rev. E /7 Fuji Elecric Co., d. All righs reserved.
Fuji Power MOSFE Design ool Cher 4. Clculing elecric ower [W] from elecric energy [] As indiced in Figure 3, red he volge nd curren vlues of wveform for he eriod. Use he red vlues nd formul (4) o clcule he loss. V V 3 3 V D 3 4 5 /f Figure 3: Red volge nd curren vlues from wveform exmle By clculing he loss for ech of he secis [s] o 5 [s], he loss for ech of he secis [] o 5 [] cn e derived. Since MOSFE is elecriclly cducing in he seci [s], he volge is roduc of he MOSFE's ON-resisnce R ON nd he curren. Formul (5) o (9) show exressis for ech of he secis. he eriod [s] is lso inverse of frequency f [Hz], herefore he ower P [W] csumed y MOSFE cn e oined from formul (). Noe h he following formuls re simlified o he finl fo sed he volge nd curren sloes nd zero-cross. Formuls for ech ern re shown in Aendix le. V + + 3 + + Sulemenry informi <Effecive vlue curren> (5 ) RON 3 ( ) ( ) + ( ) V ( + ) (7 ) 3 3 3 ( V + V ) (8 ) 4 3 3 4 5 (9 ) ( + + + + ) f ( ) P 4 5 3 4 5 Formul () is used o oin elecric energy [] ON-resisnce R ON. n he ON-eriod, ower [W] cn e oined from effecive vlues. Using [ s he effecive curren in he seci, he ower P [W] in he ON-eriod cn e exressed y formul () from formul (). P RON RON 3 ( ) ( ) + () n he ON-eriod, MOSFE will csume he ower h is he roduc of ON-resisnce R ON nd squre of effecive curren. herefore, he ower increses qudriclly deending he increse of he curren vlue. Formul o clcule he effecive curren vries deending he curren wveform. Aendix le shows yicl wvefo nd formuls o clcule effecive vlues. Dec D_Power clculi mehod Rev. E /7 Fuji Elecric Co., d. All righs reserved.
Fuji Power MOSFE Design ool Cher 5. Clculing loss from wveform Acul oering wvefo re used for loss clculi exmle. For clculi from oering wvefo, check h he wve cycle is cler, he urn-on nd urn-off volges nd curren cn e red, nd he curren vlues cn e red in he ON-eriod. he followings show cully mesured wvefo nd red vlues. Check he ON-resisnce R ON in he d shee for MOSFE h you re using. (he following clculi uses he mx vlue ch 5, which is red from chr in he d shee.) : 7.5us Mesuremen oins Device ye Ouu ower Flyck-Cverer of he swiching MOSFE FMVN38S (V/8.A/R DS()@5 mx.94[ω]) 5W (DC:9V/3.4A) urn - OFF V/div ime 5us/div D.5A/div urn - ON No loss for urn - ON. ime ns/div D V/div.5A/div ime ns/div Z Z 3 Z 4 Z D V/div.5A/div ON eriod ON : 3.9us :.A Mesured vlues V V urn - ON us V V A A ON eriod 3.9us V V A.A Z 3ns V 4V.A.A V/div urn - OFF Z 35ns 4V 4V.A.5A Z 3 ns 4V 37V.5A.7A ime 5ns/div D.5A/div Z 4 5ns 37V 385V.7A A he red vlues re used for he loss clculi. he followings re he clculi resuls wih he resecive vlues ssigned o he formul (4). urn ON : [ ] ON eriod :. 94[ Ω]. [ 3. 9[ us] 4. 89[ u 3 Z : 3 4[ V ]. [ 3[. [ u] ( ) ] Z : 4 53 u 3 ( 38[ V ]. ) + ( 38[ V ]. [ ) (. 4[ V ]) + 4[ V ]. [ 3 3. [ ] Z3 : 5 7 u ( V ]. 8[ ) ( V ]. ) (. 8[ 4[ V ]) + 4[ V ]. [ 8. [ ] Z4 : 8 u 3 ( V ]. ) + ( V ]. ) (. 3 V ]) + 3 V ]. 3. [ ] From he following clculi resuls, he MOSFE loss P [W] h cn e clculed from wvefo is.8 [W]. [ ] + 4. 89[ u] +. [ u] + 3. 53[ u] + 8. u] + 3. 8[ u] P. 8[ W ] 7. us] Dec D_Power clculi mehod Rev. E 3 /7 Fuji Elecric Co., d. All righs reserved.
Fuji Power MOSFE Design ool Cher. Using MOSFE ower clculi ool (Excel) he loss clculi mehods descried ove re ll inended for mnul clculi. n his seci, Excel is used. his Excel file is designed o e used for he loss clculi nd chnnel emerure clculi. he file cins shee h descries how o use he ool. Plese check he cen efore using i. Seci Downlod he Excel file from he Fuji Elecric's home ge: UR h://www.fujielecric.com/ Home > Producs & Soluis > Power Semicducors > Produc nformi > Power MOSFE > Design ools < File nme > Power clculi ool_rev E.xlsx Seci Oen he downloded file, Power clculi ool_rev E.xlsx, nd click he "clculi" shee. Seci 3 nu required vlues from he oined wvefo nd he d shee of MOSFE h you re using. Use he oined wvefo in Cher 5 nd MOSFE d shee for comring he clculi. [C] nu he model of MOSFE h you re using. his cell is oil; clculi is no ffeced if i is emy. [C4, C5] Red nd inu he ON-resisnce from he Drin-Source On-se resisnce chr in he MOSFE d shee. he C5 cell is inended for MEMO. Use i o record he d such s chnnel emerure. [C] nu he swiching cycle in n [us] uni from wvefo. [F column] You cn inu volges nd currens in he OFF-eriod; however, hose d cn e omied ecuse he clculi resul is zero. he OFF-ime cn lso e omied ecuse here will e shown he difference eween he vlue inu in C nd vlues inu for urn- ON, ON-eriod nd urn-off. [G o N colum nu he red vlues of wvefo in he urn-on ime, volge nd curren vlues. n he wvefo for his documen, no d is inu since here is no inerseci of volge nd curren. [O o X colum nu he red vlues of wvefo in he ON-eriod ime nd curren vlues. For volges in he ON-eriod, roduc of R ON nd curren vlue is shown s he clculi resul. [Y o AF colum nu he red vlues of wvefo in he urn-off ime, volge nd curren vlues. nu hose vlues, nd you will see.8w in C9 s he resul of he loss clculi. he resul is he sme s hose oined when he loss clculi is mnully execued. Dec D_Power clculi mehod Rev. E 4 /7 Fuji Elecric Co., d. All righs reserved.
Fuji Power MOSFE Design ool Annex le Volge cdii Curren cdii Wveform Clculi formul V <V < V() V V () f : V : V f : : ) ( ) ) ( ) ( + ) ( V + V ) V + V V <V V() () V V ( V + V ) f : V : V V <V > V() () V V f : V : V f : : ) ( ) ) ( ) ( + ) ( V + V ) V + V V V < V() () V V V ( + ) f : : V V() V V V V () V V V > V() () V V V ( + ) f : : V V >V < V() () V V f : V : V f : : ) ( ) ) ( ) ( + ) ( V + V ) V + V V >V V() () V V ( V + V ) f : V : V V >V > V() () V V f : V : V f : : ) ( ) ) ( ) ( + ) ( V + V ) V + V Dec D_Power clculi mehod Rev. E 5 /7 Fuji Elecric Co., d. All righs reserved.
Fuji Power MOSFE Design ool Annex le Wveform Effecive vlue Averge vlue ( sin ) ω d vg π sinωd d vg d 3 + ( ) + ( ) d + vg ( + ) + d 3 d vg d Effecive vlue of synhesized wve Effecive vlue of synhesized wve cn e oined y squre roo of sum of squres of effecive vlues for ech eriod. 3 + + d + 3 d Dec D_Power clculi mehod Rev. E /7 Fuji Elecric Co., d. All righs reserved.
Fuji Power MOSFE Design ool Noe. he cen of his documen (roduc secificis, chrcerisics, d, merils, srucure, ec.) is sed he d s of Decemer,. he roducs descried in his documen re sujec o chnge wihou rior noice due o revised secificis or for oher res. f you use ny of he roducs descried in his documen, lese ge he les versi of he secificis nd check he d efore using i.. he clculi resuls h you oin vi he mehod descried in his meril should e used ly s n indici. he clculi resuls (vlues) oined using his meril do no ssure he Fuji Elecric Co. roducs nd is oeris. 3. f you need o rerin or coy ll or ori of his documen, you need wrien csen from Fuji Elecric Co. he cen of his documen is sujec o chnge wihou noice due o imrovemen or for oher res. he lici exmles or r csns descried in his documen re inended s n id of design. he vrii in rs or usge cdiis re no sufficienly csidered. When using i, lese csider vrii in rs, usge cdiis or oher fcors for design. Dec D_Power clculi mehod Rev. E 7 /7 Fuji Elecric Co., d. All righs reserved.