Chemical And Biological Treatment Of Mature Landfill Leachate

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1 Unversy f Cenral Flrda Elecrnc Theses and sserans Masers Thess Open Access Chemcal And Blgcal Treamen Of Maure andfll eachae 6 Eyad Baarseh Unversy f Cenral Flrda Fnd smlar wrks a: hp://sars.lbrary.ucf.edu/ed Unversy f Cenral Flrda brares hp://lbrary.ucf.edu Par f he Elecrcal and Elecrncs Cmmns STARS Can Baarseh, Eyad, "Chemcal And Blgcal Treamen Of Maure andfll eachae" 6. Elecrnc Theses and sserans. 9. hp://sars.lbrary.ucf.edu/ed/9 Ths Masers Thess Open Access s brugh yu fr free and pen access by STARS. I has been acceped fr nclusn n Elecrnc Theses and sserans by an auhrzed admnsrar f STARS. Fr mre nfrman, please cnac lee.dsn@ucf.edu.

2 A NON-ISOATE HAF-BRIGE BUCK-BASE CONVERTER FOR VRM APPICATION AN SMA SIGNA MOEING OF A NON- CONVENTIONA TWO PHASE BUCK by MAJ G. BATARSEH B.Sc. Unversy f Jrdan, 4 A hess submed n paral fulfllmen f he requremens fr he degree f Masers f Scence n he Schl f Elecrcal Engneerng and Cmpuer Scence n he Cllege f Engneerng and Cmpuer Scence a he Unversy f Cenral Flrda Orland, Flrda Fall Term 6 Advsr: Issa Baarseh

3 ABSTRACT The challenges mpsed n Vlage Regular Mdules VRM becme dffcul be acheved wh he cnvennal mulphase buck cnverer cmmnly used n PC mherbards. Fr faser daa ransfer, a decrease n he upu vlage s needed. Ths decrease causes small duy cycle ha s accmpaned by crcal prblems whch mpars he effcency. Therefre, hese prblems need be addressed. Transfrmer-based nn-slaed plges are n new appraches exend he duy cycle and avd he asscaed drawbacks. Hgh leakage, several added cmpnens and cmplcaed drvng and cnrl schemes are sme f he rade-ffs expand he duy cycle. The bjecve f hs wrk s presen a new dc-dc buck-based plgy, whch exends he duy cycle wh mnmum drawbacks by addng w ransfrmers ha can be negraed decrease he sze and w swches wh zer vlage swchng ZVS. Anher ssue addressed n hs hess s dervng a small sgnal mdel fr a wnpu w-phase buck cnverer as an nrducn a new evlvng feld f mul-npu cnverers.

4 T all beauful mnds u here

5 ACKNOWEGMENTS Thanks be Gd, wh always leads us n rumphal prcessn... My deepes hanks and apprecan g my advsr r. Issa Baarseh fr he rus he beswed n us hrugh hs wse supervsn. Hs enlghenng dscussns and encuragng wrds bsed my scenfc cursy and enhusasm even mre. I wuld als lke sncerely hank r. Xangcheng Wang fr hs hrugh help and cnsan suppr and encuragemen. kewse, I wuld lke express my apprecan my cmmee members r. Jhn Shen and r. Taks Kaspars. I am als graeful Mr. Peer Krnezky fr hs suppr and r. Jaber A. Abu Qahuq and Ms. Hua Zhu as well. Many hanks g my frends and lab maes: Mr. Hussam Al Arash fr hs cnagus passn and cnnuus help and suppr, Mr. Ehab Al Shbak fr hs valuable nsgh and equally Mr. Osama Abdel Rahman fr hs precus suggesns and mvang encuragemen. Als, I wuld lke hank Mr. Adje Mensah, Mr. angbn Ya, Mr. Khald Rusm, Mr. Mchael Pepper, Mr. Xu Cheng and all APECOR and Flrda PEC members and UCF eammaes. I am als ndebed Ms. Mchelle Jrdan fr helpng me n my hess. I have been blessed wh a wnderful frend and rmmae, r Wafaa Khau, whm many hanks are dedcaed fr her prayers encuragemen and fellwshp and my cusn r. Eyad Baarseh fr hs valuable help and suppr. My ulmae hanks, earnes apprecan and deep lve are deved my famly, whm I am s ndebed fr her cnnual suppr, fah and lve. v

6 TABE OF CONTENTS IST OF TABES...v IST OF FIGURES... x CHAPTER INTROUCTION.... Overvew.... Thess Oulne... 4 CHAPTER ITERATURE REVIEW Backgrund Prr Ars n Hgh Slew Rae VRM Nn Islaed Technlges I Curren Cmpensars II Seppng Inducance VRM III Acve Transen Vlage Cmpensars ATVC... Curren Injecn Mde... 3 Seady-Sae Mde Energy Recvery Mde Transfrmer Based Nn-Islaed C-C Cnverers I A eeper Insgh n a Small uy Cycle II Tapped Inducr TI Buck III TI-Buck wh ssless Clamp Crcu IV The Acve Clamp Cuple Buck Cnverer V A Nn-Islaed Half-brdge C-C Cnverer Chaper Recap v

7 CHAPTER 3 Half-brdge Buck Vlage Regular Inrducn Half-brdge Buck Cnrl Schemes Symmerc Half-brdge Buck Cnverer: Asymmerc Half-brdge Buck Cnverer: HBBC Mdes f Operan Symmerc Half-brdge Asymmerc Half-brdge Smulan Resuls Turns Ra vs. Effcency Small Sgnal Mdelng Chaper Recap CHAPTER 4 MAGNETICS ESIGN AN EXPERMINTA RESUTS Inrducn Prperes and Characerscs f Magnec Cres sses Cre and Hyseress sses Eddy Curren sses Skn Effec Wndngs Expermenal Resuls Chaper Recap CHAPTER 5 MUTIPHASE BUCK v

8 5. Inrducn Cnvennal Mulphase Buck Seady-Sae Analyss Gan Equan Rpple Calculan Analyss Small Sgnal Mdelng Chaper Recap... CHAPTER 6 SUMMARY Cnclusn Fuure Wrk... 6 REFERENCES... 7 v

9 IST OF TABES Table.. Inel eskp Mherbards n GA Table.. Inel eskp Mherbards n mpga Table..3 Example Specfcans fr Inel Mcrprcessrs... Table 3.3. Vlage and Curren Sress Analyss fr he Symmerc HBBC Table 3.3. Vlage and Curren Sress Analyss fr he Asymmerc HBBC Table 3.5. Turns Ra versus Effcency Table 4.. Cre Maeral Cmparsn v

10 IST OF FIGURES Fgure.. PGA Package and Scke... 7 Fgure.. GA Package and Scke... 7 Fgure..3 GA 775 and mpga 478 Packages... 7 Fgure..4 GA Scke Assembly Vew... 8 Fgure..5 Inel eskp Mherbard... 9 Fgure..6 A Blck agram f a Mherbard... 9 Fgure..7 Inel Radmap f a 3-b CPU shwng a CPU e Vlage and b Curren emand and Slew Rae... Fgure..8 A Cncepual Blck f he Mherbard Man Pwer Surce... Fgure..9 A Smple Basc Buck Cnverer... 3 Fgure.. An Inerleaved N phase Buck Cnverer... 4 Fgure.. near Mde Curren Cmpensar Tplgy... 7 Fgure.. Swchng Mde Curren Cmpensar Tplgy... 8 Fgure..3 The Basc Cnfguran f he Seppng Inducance Crcu... 9 Fgure..4 ATVC Crcu... Fgure..5 Seres ATVC Implemenan Crcu... Fgure..6 Parallel ATVC Implemenan Crcu... Fgure..7 Cncepual Parallel ATVC Implemenan Crcu... 3 Fgure..8 The TI-Buck Crcu... 8 Fgure..9 Rearranged TI-Buck... 3 Fgure.. The TI-Buck wh ssless Clamp Crcu... 3 x

11 Fgure.. Tp Swch Curren and uy Cycle Relan... 3 Fgure.. The Acve Clamp Cuple Buck Cnverer Fgure..3 Nn-Islaed Half-brdge Cnverer Fgure 3.. Half-brdge Buck Cnverer Crcu Cnfguran Fgure 3.. Swchng Wavefrms f he Symmerc Half-brdge Buck Cnverer Fgure 3.. Mde I f he Symmerc Half-brdge Buck Cnverer... 4 Fgure 3..3 Mde II f he Symmerc Half-brdge Buck Cnverer... 4 Fgure 3..4 Mde III f he Symmerc Half-brdge Buck Cnverer... 4 Fgure 3..5 Swchng Wavefrms f he Asymmerc Half-brdge Buck Cnverer Fgure 3..6 Mde I f he Asymmerc Half-brdge Buck Cnverer Fgure 3..7 Mde II f he Asymmerc Half-brdge Buck Cnverer Fgure 3.3. Key Wavefrms f Symmerc Half-brdge Buck Cnverer Fgure 3.3. Mde I In he Analyss f Symmerc Half-brdge Buck Cnverer Fgure Mde II In he Analyss f Symmerc Half-brdge Buck Cnverer Fgure Mde III In he Analyss f Symmerc Half-brdge Buck Cnverer... 5 Fgure Mde III In he Analyss f Symmerc Half-brdge Buck Cnverer... 5 Fgure Mde IV In he Analyss f Symmerc Half-brdge Buck Cnverer... 5 Fgure Mde V In he Analyss f Symmerc Half-brdge Buck Cnverer... 5 Fgure Mde V In he Analyss f Symmerc Half-brdge Buck Cnverer Fgure Mde I In he Analyss f Asymmerc Half-brdge Buck Cnverer Fgure 3.3. Mde II In he Analyss f Asymmerc Half-brdge Buck Cnverer Fgure 3.3. Mde II In he Analyss f Asymmerc Half-brdge Buck Cnverer Fgure 3.3. Mde I In he Analyss f Asymmerc Half-brdge Buck Cnverer x

12 Fgure 3.4. Smulan Crcu fr a Symmerc HBBC... 6 Fgure 3.4. Swchng Wavefrms Smulan Resul fr a Symmerc HBBC... 6 Fgure Smulan Resuls fr a Symmerc HBBC... 6 Fgure 3.6. p and Cmpensaed Sysem Frequency Respnse Fgure 4.. Transfrmer Equvalen Crcu... 7 Fgure 4.3. Effec f Skn eph Fgure 4.5. PC44EE6-Z Transfrmer Fgure 4.5. PC44EE6-Z Transfrmer Mdel Fgure PC44EE6-Z Transfrmer Smulan Fgure Prype # wh PC44EE6-Z Transfrmer Fgure Expermenal Resuls Usng PC44EE6-Z... 8 Fgure PC95ET8/7.3Z Transfrmer... 8 Fgure PC95ET8/7.3Z Transfrmer Mdel... 8 Fgure PC95ET8/7.3Z Transfrmer Smulan... 8 Fgure Prype # wh PC95ET8/7.3Z Transfrmer... 8 Fgure 4.5. Expermenal Resuls Usng PC95ET8/7.3Z... 8 Fgure 5.. Sngle Phase Buck Cnverer Fgure 5.. Cnvennal Mulphase Buck Cnverer Fgure 5..3 The Tp Swch Curren and uy Cycle Relan Fgure 5.. Sngle Phase Buck a Crcu and b Swchng and Inducr Wavefrms 88 Fgure 5.. Cnvennal Mulphase Phase Buck a Crcu and b Key Wavefrms 9 Fgure 5..3 Mul-Inpu Mulphase Phase Buck Crcu Cnfguran... 9 Fgure 5..4 Mul-Inpu Mulphase Phase Buck rvng Wavefrms x

13 Fgure 5..5 Mul-Inpu Mulphase Phase Buck Key Wavefrms Fgure 5.3. Phase One rvng and Inducr Wavefrms Fgure 5.3. Phase Tw rvng and Inducr Wavefrms Fgure Mul-Inpu Mulphase Cnverer a Crcu and b rvng Sgnals Fgure Inducr Curren n Phase f a Tw-Inpu Tw-Phase Cnverer... Fgure Inducr Curren n Phase f a Tw-Inpu Tw-Phase Cnverer... Fgure Tal Inducrs Curren n a Tw-Inpu Tw-Phase Cnverer... Fgure 5.4. Mul-Inpu Tw-Phase Buck a Crcu and b Inducr Vlages... 4 Fgure 5.4. Inpu Curren n a Phase One b Phase Tw... 6 Fgure Inpu Curren f he Frs Phase... 9 Fgure Inpu Curren f he Secnd Phase... 9 Fgure Energy Srage Elemen Number nducr n he frs phase... 9 Fgure Energy Srage Elemen Number nducr n he secnd phase... Fgure Energy Srage Elemen Number 3 upu fler capacr... Fgure Bde Pl f a Tw-Inpu Tw-Phase Buck Cnverer... x

14 CHAPTER INTROUCTION. Overvew Pwer supples are he cre elemen n ms f he elecrcal equpmen needed day. ads can be very crcal n he sense ha hey need be fed wh a cnsan, hghly regulaed npu pwer. Cmpuer prcessrs are ne such example f crcal lads, whch s why he slver bx pwer supply n he cmpuer case cann be drecly cnneced he mcrprcessr. Insead, s cnneced a dc-dc cnverer, he upu f whch feeds he prcessr. Pn f ad PO regulan has replaced he ld cenralzed pwer bx due s vcny he mcrprcessr, whch resuls n a clsed dc-dc cnverer beng dedcaed delver he pwer needed by he mcrprcessr. Ths has allevaed he undesred effec f he parasc elemens ha exsed n he ld sysem. These POs are called Vlage Regular Mdules VRM. The rend have lw vlage VRMs as a mcrprcessr s pwer supply s ncreasng due he benef f lwer pwer lss and faser daa ransfer. Hence, he nally used pwer delvery srucure, whch adped a cenralzed slver bx supply he lad, became unsuable fr meeng he challenge f lw upu vlage due he ressve and nducve parascs. The equvalen nducance f he regular s he barrer f upu curren slew rae; fr lwer rpple curren and cnsequenly lwer rms curren resulng n lwer pwer lss, he upu nducr shuld be large. On he her hand, large nducrs mean

15 slwer ransen respnse. I s a desgn challenge faced by swchng cnverer engneers cmpensae bh cases. Fas ransen respnse under fas lad change s a crucal ssue n dc-dc cnverers wh mdern mcrprcessrs [-5]. ynamc respnse f he cnverer has been a research fcus enhance he ransen respnse f he cnrl lp durng sgnfcan sep-up and sep-dwn lad cndns, whch may reach A/us [-7, 9, - 4, 7-8]. The man VRM cann handle he requred fas ransen effecvely due s large fler nducance, whch s needed decrease he upu curren rpple. The delay mes f he cnrller, C fler and he cmpensan newrk als add sme resrcns n hw fas he VRM can respnd any lad change. Therefre, many effrs have been pu n ncreasng he ransen respnse f he VRM [-7, 9, - 4, 7-8]. A cnvennal sep-dwn buck cnverer s he buldng blck f any VRM, bu due he hgh upu rpple, an nerleaved mulphase buck replaced he buck wh he same Vl npu [3]. Anher pssble slun s parallel several cnverers, each wh a large nducr, whch resuls n a small verall nducance value; hwever, he seady-sae perfrmance wll sll n be sasfacry due hgher lsses. A seppng nducr nrduces a mehd acheve a fas ransen respnse durng lad varan, and a he same me guaranees lwer curren rpple durng nrmal seady-sae mde. Ths s dne by havng w dfferen nducr values n seres. The smaller value dmnaes durng ransen perd and he larger durng seady-sae [4, 3]. The upu suffers frm w vlage spkes ha ccur durng sep-up and sepdwn cndns [5]. The mehds and suppressn echnques develped s far fcused

16 manly n decreasng he secnd vlage spke as here s n cnrl ver he frs spke due s very shr me perd and s dependency n he capacr parasc. The curren cmpensan echnque enhance he upu vlage durng ransen s based n w njecn mehds: lnear and swchng [-6]. Acve Transen Vlage Cmpensar ATVC appraches he prblem n a smlar ye ppse way. I reles n njecng a vlage surce nsead f curren [5]. ATVC smply acs as anher buck cnverer bu wh smaller nducance and a a much hgher frequency. The small nducr helps by ncreasng he slew rae f he curren, and hereby mnmzng he curren suppled by he upu capacrs and decreasng he vlage spke a he lad sde. The nrducn f he ransfrmer n he ATVC crcu helps n reducng he curren n he swches, whch wll decrease he pwer lss. On he her hand, he lwer urns ra a he secndary sde wll ncrease he curren suppled he lad. The echnques menned s far fcus n ncreasng he ransen respnse durng lad change. Neverheless, hey suffer frm a small duy cycle resulng frm seppng he Vls npu dwn he requred ne Vl a he lad sde. Effrs have been dreced n nn-slaed, ransfrmer-based buck plges enlarge he duy cycle, ncludng apped nducr buck, acve-clamp cuple buck and frward and push pull cnverers name a few [7-3]. 3

17 . Thess Oulne A cncse vervew f hs wrk s presened n Chaper One, n whch he prblem s brefly addressed and he w majr echnques slve he prblem are saed. Invesgan f an Inel radmap shws he rend f lwerng he upu vlage and ncreasng he curren and pwer denses f fuure VRM. Effrs k w research drecns n redesgnng he curren VRM mee he new requremens f he nex generan prcessrs. Chaper Tw nrduces he backgrund f he wrk, dscussng n deal all aspecs f he VRM challenges and lmans. Tw man upu vlage spkes ccur a he lad sde, and passve and acve mehds were deeply examned allevae such spkes. The passve mehd f addng mre capacrs s lmed by space and cs. Acve cmpensan mehds, whch vary frm curren vlage njecn, are suded n Chaper Tw. In Secn., he cmplee scenar f VRM requremens s presened and he accmpaned challenges are dscussed. Secn. revews prr ars, whch were dedcaed slvng he prblem by passve and acve means. Transfrmer-based plges are dscussed n Secn.3. The new prpsed plgy, whch s based n a half-brdge buck, s gven n Chaper Three. The half-brdge buck ffers an exended duy cycle and avds he prblems asscaed wh small duy ras. ealed dscussn and analyss are gven n hs chaper. Chaper Fur gves an nsgh n he magnec par f he half-brdge buck presened earler and prvdes a desgn apprach and expermenal resuls. The halfbrdge buck has a flyback ransfrmer as he cre f s peran. Smulan resuls 4

18 shw he severe mpac f leakage n cnverer effcency and he need fr a sld and gh magnec desgn. Mul-npu cnverers are nrduced n Chaper Fve wh a cmplee smallsgnal mdelng f a w-npu cnverer. Small-sgnal mdelng s nevable n cnrl desgn. A w-phase buck wh dfferen npus s analyzed n deal. Crcu averagng and Mddlebrk s sae space averagng are appled, and cnsequenly, a small-sgnal mdel s derved. The cnclusn and fuure wrk are summarzed n Chaper Sx. 5

19 CHAPTER ITERATURE REVIEW. Backgrund Radmaps f semcnducr and mcrprcessr cmpanes cnnue call fr he lwerng f he upu vlage f he VRM values less han ne Vl and are expeced even decrease mre []. Meanwhle, VRM swchng frequency s pushed hgher fr he purpses f decreasng he cmpnen sze and enhancng he ransen respnse. The cmpuer prcessr s cnneced he mherbard hrugh a scke, whch serves as an nerface beween he mherbard and he prcessr, and allws fr elecrcal cnnecvy and easy remval replace he prcessr when needed []. Sckeng echnlgy has mved frm he mcr Pn Grd Array mpga he and Grd Array GA because f sme lmans ha are beynd he scpe f hs hess []. Inensve effrs a Inel have prduced he GA 775 scke []. Tables.. and.. shw Inel Mherbard versns n GA 775 and mpga 478 sckes [3]. Table.. Inel eskp Mherbards n GA 775 Chpse Inel eskp Mherbard Inel 95GV Express Chpse Inel 95 G Express Chpse Inel eskp bard 95GVG Inel eskp bard 95GUX 6

20 Table.. Inel eskp Mherbards n mpga 478 Chpse Inel eskp Mherbard Inel 865PE Chpse Inel 865P Chpse Inel eskp bard 865 PESO Inel eskp bard 865 PCK Inel eskp bard 865 PC The dfference beween sckes PGA and GA s ha GA has smaller fewer number f pns and a reduced cs. Fgures.. and.. shw he w dfferen sckes []. Fgure..3, shws bh mpga and GA packages []. Fgure.. PGA Package and Scke Fgure.. GA Package and Scke Fgure..3 GA 775 and mpga 478 Packages 7

21 The package cnsss f a scke husng wh sched cnacs, a sffener plae, a lad plae and a lad lever as shwn n Fgure..4. Fgure..4 GA Scke Assembly Vew Fgure..5 shws a pcure f a cmplee assembly f an Inel mherbard 95GUX versn. wh VRM cmpnens and GA package [4-5]. 8

22 8 ceramc caps Nrh VR 6 Oscns Eas VR 4 Oscns Fgure..5 Inel eskp Mherbard The verall crcu can be depced n he blck dagram shwn n Fgure..6. Vlage Regular VR Mherbard Scke Package R,, C R, R,, C CPU de Fgure..6 A Blck agram f a Mherbard Accrdng he Inernanal Technlgy Radmap fr Semcnducrs ITRS, Semcnducr Indusry Asscan SIA and Inel s radmap, he perang vlage s 9

23 decreasng cnnuusly values less han One Vl alng wh ncreasng he prcessr curren exceedng A. Sme example specfcans fr Inel mcrprcessr are shwn n Table..3 [6-9]. Table..3 Example Specfcans fr Inel Mcrprcessrs Parameer/Prcessr Penum II Penum III Penum 4 33M 6M.4G Clck Speed Hz 66M 55M.5G 3M 45M.7G Cre Vlage V mn. /max /.7.555/.7.53/.7 Cnverer Vlage V mn. /max /.7.65/.7.6/ Cre Curren A Cnverer Curren A Cre Curren Slew Rae A/ µ s Cnverer Curren Slew Rae A/ µ s - - 5

24 Inspecng he numbers n Table..3, can be ned ha here s a huge curren ncrease frm 4A n Penum II abve 5A n Penum 4 versus he drp n vlage frm.8v.6v n he same prcessrs versns menned abve. Fgure..7 Inel Radmap f a 3-b CPU shwng a CPU e Vlage and b Curren emand and Slew Rae Fgure..7 cnfrms he precedng dscussn; he CPU wll be expeced run wh a vlage belw he ne Vl level and currens hng he A as fas as 4A/us []. The man pwer surce avalable n he mherbard prvdes hree pwer levels: V, 5V and 3.3 V upu as depced n Fg...8. Fgure..8 A Cncepual Blck f he Mherbard Man Pwer Surce

25 As seen n he Inel radmap shwn n Fg...7, n he lae 99s, he CPU needed Vls, whch were nally suppled frm he 5 Vls pr [9]. Hwever, he ressve and nducve parasc elemens beween he pwer surce, knwn as he slver bx, and he CPU dramacally affec he quany, as well as he qualy a he CPU npu, -.e. he lad. Wh he ncreasng rend f lwerng he upu vlage, hs pwer flw scheme culd n be acceped r used any lnger. Hence, he pn f lad PO cnverer, whch was placed clse enugh he lad, replaced he prevus pwer flw. Agan, he cenralzed slver bx was n lnger used due he parasc effec added, whch placed a resrcn n furher lwerng f he upu vlage. Cnsequenly, dedcaed dc-dc cnverers came play an mpran rle n he CPU ndusry. VRMs became he cener f he mherbard. Wh he cnnuus decrease n he CPU vlage, and an analgus ncrease n he curren, he npu vlage shfed he Vls pr [9] The ms smple and lgcal mehd acheve he lw upu vlage frm he Vls npu s have a vlage surce sepped dwn he requred CPU vlage level. The buck cnverer s herefre he crnersne n any VRM. A buck cnverer s merely a level seppng-dwn crcu cnssng f a swchng newrk, whch s manly N-channel MOSFET and a lw pass fler, as shwn n Fgure..9, where he npu vlage s sepped dwn n accrdance wh he swchng mechansm prduce an upu vlage ha s less han he npu by a facr equal he duy cycle f he man swch. The swchng par f he crcu s fllwed by a flerng newrk smh u he spkes and supply he lad wh a clean upu vlage f he desred value. The

26 cnrl varable n hs case s he duy cycle; n her wrds, he upu vlage s deally prprnal he duy cycle. Fgure..9 A Smple Basc Buck Cnverer Cenral Prcessng Uns CPUs n cmpuers are reaed as crcal lads n VRM leraure. The challenges VRM desgners face are cmpaced n w aspecs: The clean, cnsan and lw-upu vlage he CPU needs, geher wh hgh curren and pwer denses, add hermal ssues he desgn cmplexy. The fas ransen respnse s equally mpran as n he CPU realm. Wh he abve desgn cnsderans n mnd, s bvus ha a sngle-phase buck cnverer wll n mee he CPU requremens due he large nducr rpples ha he sngle buck presens. The shf nerleaved mulphase buck was nevable [3]. An nerleaved mulphase buck cnverer effcenly replaced s sngle phase cunerpar mprvng he ransen respnse and ncreasng he effcency. Fgure.., shws an N phase buck cnssng f dencal N phases shfed by 36 / N. Ths cnrl scheme bvusly decreases he upu curren rpples. The lwer he curren rpple, he 3

27 lwer he rms curren, whch means he lwer he lsses. Ths can als mean beer effcency and beer hermal managemen. Fgure.. An Inerleaved N phase Buck Cnverer As dscussed earler, he npu he VRM has been swched frm he 5 Vl he Vl pr. Thus, here s a C Vlage surce a he npu f a mulphase buck cnverer ha supples he prcessr f he mherbard wh he lw vlage needs. The lwer he upu vlage, he less he pwer cnsumpn and he faser he daa ransfer becmes. Therefre, he fuure rend s furher decrease he vlage and cnsequenly ncrease he curren. The amun f daa handled by he prcessr vares wh he number f prgrams beng run ha cmprse he prcessr lad. The lad may n nly change frm n lad full lad, bu can d s wh a very hgh slew rae up A/us []. 4

28 When he lad change ccurs, wheher sep-up r dwn, he dfference f he curren shuld be handled. In he case f sep-up lad, he exreme scenar s when he lad changes frm n lad full lad. When hs happens, he upu vlage ends decrease, bu n rder manan a cnsan upu vlage, curren njecn wll be needed frm he surce whch leads ncrease he duy cycle be able supply he lad wh he curren needs. Befre he VRM supples he upu lad cmpleely, he upu capacr wll help n supplyng he curren needed, and hus a vlage spke wll ccur a he upu vlage. In an analgus way, when sep-dwn lad happens, energy sred n he fler nducr needs be recvered and hus he ff me n surce perd ncreases unl all he energy ha was sred n he fler nducr s cnsumed. In he abve cases, he cnrller, he C fler, and he cmpensan newrk delay mes wll deerrae he vlage spke a he upu. In shr, here are w vlage spkes ha appear a he upu, and her presence s a prblem and her remedy depends n he undersandng f her rgnal surce. The frs vlage spke s deermned by he capacr parasc ESR and ES and als by he upu curren slew rae SR. The secnd spke s deermned by he energy sred n he nducr. Only passve mehds can reduce he frs vlage spke by addng mre upu capacrs reduce her equvalen seres ressance and nducance, whch s cs and space lmed. As seen n Fgure..5, many OSCON and ceramc capacrs are dwelled clse he CPU and ccupy a l f space n he mherbard [4, 5]. The frs vlage spke s alms cnsan fr a ceran upu fler nducance value, and s hardly dependan n he nducr value and manly reles n he parasc values f he capacr. The nly way f elmnang he spke s add mre upu 5

29 capacrs n parallel, hus decreasng he ESR and ES. Ths passve mehd s lmed by he avalable free space n he mherbard and by he cs. The secnd spke s cnrllable, and s hghly dependen n he fler nducance. The smaller he nducr he faser he ransen respnse, and hus, he less he charge and he smaller he vlage spke becmes. In her wrds, he frs vlage spke dmnaes when a small fler nducr s used a whch he secnd spke s elmnaed due he hgh ransen respnse. Smlarly, he larger he nducr value, he slwer he ransen respnse and he larger he vlage spke. Thus, he secnd spke dmnaes wh a large fler nducance. Cnsequenly, here are w desgn mehds: he frs mehd s an ESR- and ES-based ransen desgn wh a small fler nducance [9]. The secnd desgn mehd s an energy-based desgn prcedure wh a large upu fler nducance. As menned earler, hse spkes are deerraed wh nn-deal cnrllers. All praccal cnrllers suffer frm delay mes, whch when added he delays resulng frm IC prpagan me and C newrk wll have even mre mpac n ncreasng he spkes.. Prr Ars n Hgh Slew Rae VRM Ths secn presens prevus appraches desgnng VRMs mee he srngen requremens f he VRM desgn. There are w man felds n VRM: nnslaed plges whch fcus n enhancng he ransen respnse [-9, -4, 7-8], and slaed plges n whch a ransfrmer s appled exend he duy cycle [5-9]. These w VRM plges are dscussed n hs secn. 6

30 .. Nn Islaed Technlges..-I Curren Cmpensars As saed befre, he prblem f he nably f he man vlage regular n supplyng he lad wh he needed curren under-lad changes s f grea cncern. Therefre, curren cmpensars are based n he dea f njecng he curren needed durng ransens nsead f relyng n he upu capacrs prvde he lad curren. Curren cmpensan njecs curren n w mdes: lnear mde curren cmpensars, [-3] and swchng mde curren cmpensars, [5-6] as shwn n Fgures.. and.., respecvely. In bh plges, he unbalanced curren s suppled by he exra cnverer and resuls n hgh-curren sresses. Fgure.. near Mde Curren Cmpensar Tplgy 7

31 Fgure.. Swchng Mde Curren Cmpensar Tplgy The auxlary crcu prvdes he unbalanced curren n eher a lnear r a swchng mde. The man dsadvanage n he lnear cmpensar s he cnducn lsses, and n he swchng cmpensar, he dsadvanage s he swchng lsses ha resul n a majr decrease n effcency f he verall cnverer, makng curren cmpensars very dffcul n lw-vlage and hgh-curren applcans...-ii Seppng Inducance VRM Fgure..3 shws he basc cnfguran f he seppng nducance where, nducr r s smaller han [4]. 8

32 V S S V M aux r V n M C R V - Fgure..3 The Basc Cnfguran f he Seppng Inducance Crcu S s prgrammed urn n durng ncreased-lad ransens and S urns n durng decreased-lad ransens shr crcu he larger nducr n bh cases [4]. When S urns n, he ne nducance decreases, leavng he smaller ne be used, and hs wll ncrease he upu nducr slew rae durng ha perd, resulng n a reduced vlage devan [4]. A sep-up lad, he upu vlage decreases, and as a resul, S urns n, whch als decreases he upu nducance. Ths wll ncrease s slew rae unl he curren n he leakage nducance reaches he upu curren, and hen V sps decreasng and sars ncrease. When reaches a ceran value, S urns ff, and nce agan, akes ver he upu nducance and s curren dmnaes. Hwever, snce s sll less han he upu-lad curren, he upu vlage wll decrease agan, and cnsequenly, S wll urn n nce he upu vlage reaches a value less han a ceran hreshld. Ths scllary n and ff swchng f S sps nce he equals he upu lad curren I [4]. 9

33 Havng a vlage surce, V serves n keepng he large nducr curren ncreasng durng he me perd when M and S are n. Ths furher decreases he ransen perd and resuls n a faser ransen respnse manan a cnsan upu vlage he lad. The same peran akes place n a reverse rder a lad sep-dwn swchng S n and ff [4]...-III Acve Transen Vlage Cmpensars ATVC Acve ransen vlage cmpensar ATVC appraches he prblem n a smlar ye ppse way. I reles n njecng vlage surce nsead f curren. Fgure..4 shws he ATVC crcu [5]. ATVC smply acs as anher buck cnverer, wh smaller nducance and a much hgher frequency. The small nducr helps ncrease he slew rae f he curren and hus mnmzng he dfference beween he upu curren and he curren frm he man VRM. Once hs dfference decreases, he upu capacr charge decreases and leads lwer vlage spke a he upu. As shwn n Fgure..4, ATVC cnsss f a ransfrmer wh N urn ra, w auxlary swches S a and S a and a vlage surce V ha can be f any value.

34 Fgure..4 ATVC Crcu The nrducn f he ransfrmer helps n decreasng he curren n he swches. Ths wll decrease he pwer lss, frm whch he curren cmpensan mehds suffer. On he her hand, he lwer urn ra a he secndary wll ncrease he curren suppled he lad. The man VRM peraes a relavely lw frequences mananng gd effcency values. ATVC cmes n w cnfgurans: seres and parallel, whch are shwn n Fgures..5 and..6, respecvely.

35 Fgure..5 Seres ATVC Implemenan Crcu S Parallel ATVC Crcu S R P R P V n Tx C p R V - S a V S N N S a S N C Fgure..6 Parallel ATVC Implemenan Crcu The nly dfference beween seres and parallel ATVC s ha seres ATVC handles all he unbalanced curren beween he man VRM and he lad, whereas parallel ATVC carres nly a prn f ha curren accrdng he vlage dvder K f R p and R M, fllwng he equan; K R R P R P M

36 Where: R p s he equvalen ressance f he races and he parasc, and, R M s he magnezng nducance ressance as shwn n Fgure..7. Fgure..7 Cncepual Parallel ATVC Implemenan Crcu Hence, parallel ATVC curren sress s less han ha n seres ATVC. Als, seres ATVC ncreases he sac lad lne, and ye, he ransen lad lne mprvemens f bh ATVC ypes are he same. The cmplee cycle f ATVC can be dvded n hree mdes f peran: curren njecn mde, seady-sae and energy recvery mde. Curren Injecn Mde Ths s he perd f me durng whch he lad curren ncreases abruply. Cnsequenly, he upu vlage decreases accrdng he pwer cnservan durng 3

37 hs mde when ATVC kcks n help he man VRM n supplyng he curren needed a he lad sde. The small leakage nducance s wha s needed ncrease he slew rae f he curren njeced by he ATVC, s ha he curren s quckly suppled he lad whu he help f he upu capacrs, decreasng he charge dfference and cnsequenly decreasng he vlage spkes a he upu. When he lad curren ncreases, he upu vlage wll cnsequenly decrease a ceran lm when S a urns n. A hs nsance, ATVC s acvaed, and he curren supplyng he lad s he addn f he curren frm he man VRM plus he curren frm ATVC. ue he small leakage nducance, he curren rses very quckly wh a hgh slew rae. The ransn beween he n and ff saes f S a and ff and n saes f S a wll cnnue unl he magnezng curren man VRM reaches he upu needed curren and he upu vlage reaches V. Ths perd f me s wha s knwn as curren njecn perd. Seady-Sae Mde Once he curren suppled he lad frm he man VRM, alng wh he added curren frm he ATVC sde, reaches he curren needed a he upu, hen he ATVC can g n sandby mde. I shuld be ned here ha wh he nrducn f he ransfrmer wh N urns ra, ATVC handles a curren N mes less han ha handled by he curren cmpensars hus reducng he cnducn and he swchng lsses. In addn, prvdes a curren N hgher han ha f he prevus ars wh same fler nducance. 4

38 urng he seady-sae mde f peran bh auxlary swches S a and S a urn ff. The bdy dde f S a shuld n urn n durng hs mde and hs can be guaraneed by sasfyng he fllwng cndn: N V < V V S Where: Vs s he secndary vlage f he ransfrmer and V s he n-sae vlage drp f he bdy dde f S a. Snce he vlage drp acrss R p s small, he abve cndn can be me easly. 3 Energy Recvery Mde The las mde f peran s he energy recvery mde. urng hs perd, he lad curren seps dwn wh a very large negave slpe, hus he upu vlage ncreases. The excess energy shuld be recvered, and hs s dne by makng he ATVC ac as a bs cnverer by cnrllng S a. Ths mde s he mrrr ppse f he curren njecn mde n ha he same lgc s appled, bu nsead f ncreasng he curren, he drecn s aken n recverng he energy dschargng he curren n he nducrs feedng back he supply vlages. Ths mde wll cnnue unl he upu vlage decreases he requred value. In summary, ATVC njecs hgh slew rae curren n sep-up lad and recycles exra energy sred n he VRM fler nducr n s npu vlage V durng sep-dwn lad. 5

39 .. Transfrmer Based Nn-Islaed C-C Cnverers As menned earler, a cnvennal sep-dwn Buck cnverer s he buldng blck f any VRM, bu due he hgh upu rpple, nerleaved-mulphase buck replaced he smple sngle-phase buck wh he same Vls npu. The seppng dwn frm he Vls npu he requred ne Vl a he lad sde enals a very small duy cycle, and added ha s he hgh swchng frequency ha resuls n sme asscaed prblems and lw effcency. Effrs have been dreced n nn-slaed ransfrmer-based buck plges slve he abve menned prblems, ncludng apped nducr buck, acve-clamp cuple buck and frward and push pull cnverers name a few [6-9]...-I A eeper Insgh n a Small uy Cycle The majr prblem asscaed wh lw upu vlage and hgh swchng frequency s havng a small duy cycle as menned abve. Ths s cnsdered he surce f all her accmpaned lmans as lsed belw [9-3]: - A fas cmparar s needed creae he small drvng sgnal, whch wll ncrease he cs. - The p swch cnducn perd decreases wh he ncreasng f he swchng frequency, whch may cause a malfuncn f he cnverer, knwn as gae drve prblems, and ha cause an ncrease n he swchng lsses f he p swch and cnsequenly ncrease he cnducn lss f he lwer swch. 3- Asymmerc ransen respnse causes a clear dfference n he sep-up and sepdwn speeds. 4- Effcency wll drp due he hgh peak curren ha s asscaed wh he small duy cycle and he lng cnducn perd f he bm bdy dde swch. 6

40 The prblems asscaed wh a small duy cycle are f grea mprance especally wh he accmpaned ncrease f swchng frequences mprve he ransen respnse and decrease he sze. T address he small duy cycle ssue, desgners used cupled magnec cnfguran ncludng apped nducr, cupled buck cnverers [6, 7] and he nn-slaed Push Pull Cnverer [8, 3]. The sragh frward slun he abve prblem s add anher cnrl parameer besdes he duy cycle, whch allws us decrease he upu vlage and manan an pmum duy cycle and cnsequenly avds he prblems relaed smallduy ras. Transfrmer-based nn slaed-dc-dc cnverers were freseeable and an expeced slun. I helps acheve he desred lw-upu vlage and, a he same me, susan a relavely hgh duy cycle wh beer rpple cancellan and lwer swchng currens [3]. I s essenal here sress he fac ha fr many V mcrprcessr pwer supples, whch are he subjec f hs sudy, here s n slan requred [3]. Ths explans why VRM desgners are nclned wards ransfrmer-based ye nn-slaed dcdc cnverers. Tw f he VRM requremens cme back back. The upu vlage s n cnnuus decrease and he need fr smaller passve cmpnens and faser ransen respnse dcae he shf hgher swchng frequences. Bu, hs desn cme easly r empy handed, as he lwer he upu vlage, he lwer he duy cycle. Wh he necessy f hgher swchng frequency, he effcency wll g dwn as well. Hence, here s jusfcan add a ransfrmer creae a new VRM famly desgnaed fr he 7

41 ransfrmer-based nn-slaed dc-dc cnverer, whch ncludes: he apped nducr buck cnverer [6] wh s wn crcu wh lssless clamp crcu [9] he acve clamp cuple buck cnverer [7], push pull buck [8] and he nn-slaed half-brdge [9]. Each f hese cnverers adds an advanage and a cnrbun fr slvng he abve menned prblems. Bu a well-knwn rade ff ssue s ha als fals n ne aspec. The fllwng s a bref lsng f he prs and cns f he abve cnverers...-ii Tapped Inducr TI Buck As wh he case f he seppng nducance, he dea s have a smaller nducance value enhance he ransen respnse. The w wndngs w and w shwn n Fgure..8 cnsue he verall nducance n he chargng perd, whereas he small wndng, w, akes ver durng he dschargng perd [6, 9]. Fgure..8 The TI-Buck Crcu The advanages f he apped nducance are summarzed as fllws: - The avalably f anher parameer cnrl he upu vlage besdes he duy cycle allws fr a beer wder duy cycle accrdng he equan belw [6, 9]: 8

42 V n nv n V Ths allws fr slvng he prblem by exendng he duy cycle. - The msmach beween he ransen respnse speeds can be slved by precsely desgnng fr w and w [6, 9]. 3- Effcency s als clamed be beer due he n facr ha decreases he curren ha passes hrugh he p swch, and he enlarged duy cycle acheved wll decrease he cnducn perd f he bm swch bdy dde. These w cnsequences wll ncrease he effcency. On he her hand, he TI-Buck suffers frm lmans ha cunerac s abve ls f advanages. The p swch drvng scheme becmes a challenge, snce wll n be as easy as he cnvennal buck. The secnd severe lman s due leakage energy. The leakage energy f wndng w wll be ls n he resnan crcu f w, and he p swch capacr creaes a hgh vlage spke acrss he swch, whch decreases he effcency and generaes he pssbly f desryng he p swch. Thus, he wn crcu f he TIbuck wh he added clamp crcu ffered a slun fr he leakage energy. 9

43 ..-III TI-Buck wh ssless Clamp Crcu The TI-buck shwn n Fgure..8 was rearranged frm he cnverer shwn n Fgure..9. Ths new arrangemen wll slve he gae drvng prblem smply by usng he b srap crcu fr he p swch S [9]. n: w V n S S w C R V - Fgure..9 Rearranged TI-Buck Addng a lssless crcu rap he leakage energy resuled n he crcu shwn n Fgure... n: w s S V n S w s Cs C R V - Fgure.. The TI-Buck wh ssless Clamp Crcu 3

44 The mdfed TI-Buck slves he prblem f he basc TI-Buck bu wh he added cmplexy f he magnec desgn plus he lsses f he w added ddes n he clamp crcu. Therefre, he slun ffered by he mdfed TI-Buck wh he lssless clamp crcu was equally leveled by he dsadvanages f he magnec desgn dffculy and he clamp ddes lsses...-iv The Acve Clamp Cuple Buck Cnverer As dscussed befre, he synchrnus mulphase buck became he buldng blck f he VRM fr he benefs f ransen respnse mprvemen and upu curren rpple cancellan, whch help decrease he upu capacance. Neverheless, he small duy cycle lms he rpple cancellan ganed unless mre phases are added wh ncreased cmplexy. The her prblem addressed s he asymmerc ransen respnse. Reducng he nducance value and decreasng he bandwdh are w appraches adaped acheve symmerc ransen respnse n ne sde. Bu n he her pane f he balance, hese appraches decrease he effcency and ncrease he upu capacance [7]. The TI-Buck ffers a new parameer ha helps n geng he ransen respnses clser beng symmerc. Ths parameer s he urn ra f he w wndngs f he nducance. The parameer n cnrls he slpes f he chargng and dschargng perds. Therefre, he desgn challenge s ge he precse value f he urn ra n f he w 3

45 wndngs w and w, whch makes he slpes durng he w nervals f he swchng perd equal, resulng n symmerc ransens [6-7, 9]. Increasng he duy cycle wll g sde-by-sde wh decreasng he curren n he p swch s. Fgure.. shws a cmparsn beween he p swch curren s wh small duy cycle and hgher duy cycle. Ths can be ranslaed als n lwer lsses and hgher effcency. Fgure.. Tp Swch Curren and uy Cycle Relan Agan, he her shrcmng suffered by he TI-buck s he leakage energy, whch s dsspaed n he p swch capacr and creaes a vlage spke acrss he swch and culd pssbly mpar he swch. T vercme hs prblem, he 3V MOSFET s n lnger suable fr use and shuld be replaced wh a hgher vlage swch, whch can be saed as hgher R dsn whch resuls n hgher cnducn lsses [7]. Many desgners faced he challenge f cmng up wh a lssless snubber crcu allevae he spke whu negavely affecng eher he cs f addng mre cmpnens r he effcency. 3

46 Fgure.. The Acve Clamp Cuple Buck Cnverer One f he prpsed snubbers s he acve clamp cuple buck shwn n Fgure... The cmplexy f he cnrl and he magnec desgn s expeced ncludng he added cs and decreased effcency...-v A Nn-Islaed Half-brdge C-C Cnverer The nn-slaed half-brdge cnverer ffers he fllwng advanages: lwer lsses accmpaned wh he lwer peak curren and hgher duy cycle hrugh he negran f he ransfrmer wh s urn ra and he faser urn ff f S [3]. The crcu cnfguran s shwn n Fgure

47 V n C C T A S S T B C 3 V S 3 S 4 - Fgure..3 Nn-Islaed Half-brdge Cnverer As wh he case n he prevusly dscussed plges, he nn-slaed halfbrdge desn ffer he abve lsed advanages fr free. The lwer curren n he prmary branch dcaes a hgher curren n he secndary and s ranslaed n hgher cnducn lsses. A ransfrmer and an nducr are added, whch ncrease he cs as well as he asscaed lsses n he cre and cupper besdes addng he desgn cmplexy [3]. 34

48 .3 Chaper Recap Fuure VRMs are headng n lwer vlage, hgher curren and pwer denses n addn shfng he swchng frequency ranges as hgh as mega Herz n he am f decreasng he sze and enhancng he ransen respnse. Tday s cnverers suffer frm w spkes a he upu. The frs vlage spke s alms uncnrllable bu can be suppressed by parallelng dfferen knds f capacrs. Hwever, hs passve mehd s lmed by cs and space. The secnd vlage spke s deermned by he energy sred n he nducr and here are dfferen appraches lwerng. Bu alng wh lwerng, here s a bg radeff and desgn challenge. The smaller he nducr, he faser he respnse, bu he rpple becmes an ssue. The hgher bandwdh and he smaller spke shf he swchng frequency hgher band values, whch lead hgher swchng lsses and herefre lwer effcences. Effrs have been made allevae he secnd vlage spke. The cnvennal curren cmpensan was an aracve mehd f njecng hgh slew rae curren n sepup lad and absrbng he vlage versh n sep-dwn lad wheher by lnear r swchng mdes. The drawback s he large curren sress ha resuls n hgh cnducn lss n lnear mde and hgh swchng lss n he swchng mde. Acve Transen Vlage Cmpensar ATVC s a vlage njecn mehd. The pwer lss s reduced due he ransfrmer ha s beng nrduced as a val elemen n he crcu f he ATVC. I reles n njecng hgh slew rae curren durng sep-up lad and energy recvery n sep-dwn lad. 35

49 ATVC acvaes nly durng ransens wh several MHz perang frequences, whereas he man VRM remans a relavely lwer frequency range manan beer effcency. arge delay mes nhered n he cnrller, cmpensan newrk and he C fler deerrae he vlage spkes even mre. Nw, all aenn has been dreced enhance he cnrller desgn. Fnally, ATVC has mprved AC lad lne manly fr he suppressn f he secnd vlage spke wh small pwer lss. I s a very aracve way n hgh slew rae applcans. The lwer he upu vlage, he smaller he duy cycle and he lwer he effcency wll be. Many desgn appraches were aken n cnsderan ncludng addng anher upu vlage cnrl parameer. The ms lgcal slun was add a ransfrmer whle mananng he nn-slan requremen f he VRM. Tapped Inducr Buck was he rgnal slun n whch many her plges were based, and clamp crcus were desgned slve he leakage energy prblem. Oher plges were derved frm he half-brdge r push pull cnverers. Advanages were addressed geher wh s al--al lmans. 36

50 CHAPTER 3 HAF-BRIGE BUCK VOTAGE REGUATOR 3. Inrducn Inel radmap predcs ha fuure VRM wll perae a lw upu vlage hng he ne Vl lm wh an ncrease n curren and pwer denses. Smaller upu vlage ranslaes n smaller duy cycle, and hs mpars he effcency f he cnverer due he prblems dscussed n Chaper Tw. In nn-slaed plges, s used decrease he upu vlage. Hwever, fr very small upu vlage requremens, becmes very small, and hs wll resul n hgh curren and vlage sresses and herefre hgh swchng lsses. A ransfrmer s embedded n nn-slaed plges add anher upu vlage level cnrl wh an pmzed and herefre prvde lwer swchng lsses and hgher effcences. The Half-brdge Buck Cnverer HBBC presened n hs chaper ffers an added cnrl parameer allwng an exended duy cycle fr pmum peran and beer effcency. Fgure 3.. shws he crcu cnfguran fr he HBBC. V A C r n n V n S S C R S 3 S 4 Fgure 3.. Half-brdge Buck Cnverer Crcu Cnfguran 37

51 The HBBC ncrpraes w cupled nducrs, and he urn ra n nly helps reduce he upu vlage by a facr equal he recprcal f he urn ra, bu als ncreases he curren suppled he lad by he secndary sde f he ransfrmer enhancng he ransen respnse. If cmpared a cnvennal w-phase buck cnverer, he vlage acrss he lwer swches S 3 and S 4, shwn n Fgure 3.., s lwer by a facr f /n. Ths allws fr he use f lwer vlage MOSFETs wh he advanage f lwer R dsn, whch decreases he cnducn lsses cmpared a w-phase buck cnverer The curren a he prmary sde s decreased by /n, whch als decreases he cnducn lsses f he upper swches S and S. The blckng capacr, C r, hlds he average vlage, V Cr, accrdng he equan: V Cr V A V Where: V A s he average vlage f v A a he phase nde as shwn n Fgure 3.., and depends n he cnrl ype adped, symmerc r asymmerc, whch are analyzed n he fllwng secn. 38

52 3. Half-brdge Buck Cnrl Schemes 3.. Symmerc Half-brdge Buck Cnverer: The swchng wavefrms f he symmerc HBBC are shwn n Fgure 3... Fgure 3.. Swchng Wavefrms f he Symmerc Half-brdge Buck Cnverer I can be shwn ha he average value f v A s gven by: V A V n Vn Vn Vn Vn V n Therefre, V Cr Vn V 39

53 Vn And hs can be cnsdered a vlage surce f a value equal V. T derve he gan equan, we apply he vlage secnd balance acrss he nducrs, and frm he abve wavefrms, we can see ha here are hree dfferen mdes f peran: The frs mde s when S s ON and S s OFF fr he duran f T. The secnd mde s when S s ON and S s OFF, and hs mde lass fr he same duran f me as he frs mde T, snce he drvng sgnals f he swches are symmerc. And he las mde s when bh S and S are OFF. Als, he hrd mde repeas wce whn ne swchng perd, and herefre, he duran f he hrd mde s - T. Mde I T: urng hs mde, S and S 3 are ON as shwn n Fgure 3.. Fgure 3.. Mde I f he Symmerc Half-brdge Buck Cnverer The nducr vlages are gven by he fllwng relans v v nv V n V Cr nv V Where V Cr can be subsued by V Cr V n V yeld, 4

54 v Vn nv Mde II T: urng hs mde, S and S 4 are ON as shwn n Fgure 3..3 Fgure 3..3 Mde II f he Symmerc Half-brdge Buck Cnverer In hs mde, he nducr vlages can be wren as; v v nv V Cr nv V Where: V Cr Vn V Therefre, V n v nv 4

55 Mde III -T: Fgure 3..4 Mde III f he Symmerc Half-brdge Buck Cnverer In hs mde, S 3 and S 4 are ON as shwn n Fgure 3..4 and he nducr vlages are expressed as; v nv v nv Applyng he vl secnd balance n r, we ban: Vn nv nv nv Hence, he vlage gan becmes; V V n n 3.. Asymmerc Half-brdge Buck Cnverer: As ppsed he symmerc HBBC, he swchng wavefrms f he asymmerc HBBC are shwn n Fgure

56 Fgure 3..5 Swchng Wavefrms f he Asymmerc Half-brdge Buck Cnverer Where he average vlage a he phase nde n he Asymmerc HBBC s guven by: V A _ asym V n Therefre, fr he asymmerc case: V Cr V n V As ned n he asymmerc case, he blckng capacr vlage depends n he duy Vn cycle, whereas n he symmerc case s a cnsan value equal V. T derve he gan equan, we apply he vl secnd balance acrss he nducrs. Als, we have w mdes f peran as shwn n Fgure.3.5. The frs mde s when S s ON, and hs mde cnnues fr a perd f me equal T. The secnd mde s when S s OFF and S s ON fr duran f me equal - T. 43

57 Applyng he vl secnd balance fr he nducrs, we ge he gan f he cnverer as shwn belw. Mde I: T In hs mde, S and S 3 are ON whle S and S 4 bh are OFF. The equvalen crcu s shwn n Fgure 3..6: V n S C r V - n V - n V - C R V S 3 - Fgure 3..6 Mde I f he Asymmerc Half-brdge Buck Cnverer The nducr vlages are gven by: v v n V V n V Cr nv V Mde II -T: Fgure 3..7 Mde II f he Asymmerc Half-brdge Buck Cnverer 44

58 v v nv V Cr nv V Where: V Cr V n V Subsuung V Cr we ge, v V nv n Applyng he vl secnd balance n V r V, we ge: nv nv V n The vlage gan n he Asymmerc HBBC can be wren as: V V n n 3.3 HBBC Mdes f Operan 3.3. Symmerc Half-brdge The Half-brdge Buck Cnverer wll be analyzed n mre deph n hs secn, and he symmerc HBBC wll be examned prr he asymmerc. Mdes f peran and sress analyss are nspeced fr bh cnrl mehds. Fgure 3.3. shws key wavefrms f he cnverer. 45

59 S S S 3 S 4 V m V V -V n /nv V m V V -V n /nv m_max m m m_mn m_max m m m_mn m /n m /n m /n m /n n m /n m /n Fgure 3.3. Key Wavefrms f Symmerc Half-brdge Buck Cnverer 46

60 The mdes f peran f he cnverer are as fllws; Mde I: S S S 3 S 4 OFF OFF ON ON V n V S - V S - V Cr - C r I V - n - P V - P - n m C 3 4 m - - C R I V S 3 S 4 - Fgure 3.3. Mde I In he Analyss f Symmerc Half-brdge Buck Cnverer In hs mde, he man swches are ff and he energy n he magnezng nducance wll be rapped n he ransfrmer. Whereas, he secndary currens 3 and 4 wll supply he lad curren as shwn n he fllwng equans: v v 3 4 v v m m V V The equans ake n cnsderan he d nan as shwn n Fgure Therefre: v v nv nv Where he prmary wndng f he frs ransfrmer can be wren as; v v nv p m 47

61 Smlarly, v v nv p m The currens hrugh he magnezng nducance can be expressed as; m m V V m m I I m m I m I m Where: and are he nal cndns fr he frs and secnd magnezng currens respecvely. The upu capacr curren and he vlage acrss S and S are gven by; C m m I and Vn v s vs Mde II: S S S 3 S 4 ON OFF ON OFF Fgure Mde II In he Analyss f Symmerc Half-brdge Buck Cnverer 48

62 The secnd nducr acs as an nducance makng p and wh S 4 pen, 4. 4 p Examnng Fgure 3.3.3, he vlages acrss he nducrs can be wren as; Cr n V v V V v nv v V v 3 n n n nv V V nv V V V The currens hrugh he magnezng nducances are gven by; n V n V V m m n m m m m The curren hrugh he blckng capacr C r, and he upu capacr curren C are gven as; m m C m I n Mde III : - S S S 3 S 4 OFF OFF ON OFF S4 ON 49

63 Fgure Mde III In he Analyss f Symmerc Half-brdge Buck Cnverer In hs mde, S s urned ff and, befre urnng n S 4, he bdy dde f S 4 sars cnducng fr a shr perd. I s n even shwn n wavefrms, whch allws acheve ZVS fr S 4. Then, when S 4 s urned n wh ZVS, we ener mde IV. Mde III: 3 : S S S 3 S 4 OFF OFF ON ON Fgure Mde III In he Analyss f Symmerc Half-brdge Buck Cnverer 5

64 Agan, we ener a freewheelng mde n whch he lad curren s suppled by he secndary sdes, and he prmary sde raps he magnezng currens. The frs magnezng curren s negave, and he secnd ne s psve. Ths mde s n mre. ' han he exac duplcae f Mde I, wh he apprprae me shf f Mde IV: 3 4 : S S S 3 S 4 OFF ON OFF ON m m Fgure Mde IV In he Analyss f Symmerc Half-brdge Buck Cnverer The frs nducr acs as an nducance makng p and wh S 3 pen, 3. 3 P Examnng Fgure 3.3.6, he vlages acrss he nducrs can be wren as; v v v 4 V nv V V Cr m v V Vn Vn V nv nv V The currens hrugh he magnezng nducances are gven by; 5

65 m m V V n m n V m 3 m 3 3 m 3 We can nce ha bh magnezng currens reverse her slpe drecn, where m was negave, and nw s rampng up wh a psve slpe. The same apples n m bu n he ppse drecn. The curren hrugh he blckng capacr C r, and he upu capacr curren C are gven as; C m m n m I Mde V : 4 4 : S S S 3 S 4 OFF OFF OFF- S3 ON ON V n V S - V Cr - C r I V S - V - n - P V - P - n m C 3 4 m - - C R I V S 4 - Fgure Mde V In he Analyss f Symmerc Half-brdge Buck Cnverer In hs mde, S s urned ff, and befre urnng n S 3, he bdy dde f S 3 cnducs n hs mde whch s a shr perd f me and s n shwn n he wavefrms. 5

66 Ths allws achevng ZVS fr S3 and mnmzng he bdy dde cnducn lsses, Then, when S 3 s urned n wh ZVS, we ener mde V and repea he cycle. Mde V: 4 5 S S S 3 S 4 OFF OFF ON ON Fgure Mde V In he Analyss f Symmerc Half-brdge Buck Cnverer Agan, hs mde s an exac duplcae f mde I, wh he excepn f he ' apprprae me shf ha s nw. 4 As a summary f he vlage and curren sresses acrss and hrugh he swches, he Table 3.3. shws he vlages acrss he swches durng urn ff and he curren hrugh he swches whle cnducng. Table 3.3. Vlage and Curren Sress Analyss fr he Symmerc HBBC Mde II Mde I, III, V Mde IV V.S. I.S. V.S. I.S. V.S. I.S. S m V n / V n S V n V n / - m S V n /n S 4 V n /n

67 3.3. Asymmerc Half-brdge Mdes f Operan: Mde I: : T S S S 3 S 4 ON OFF ON OFF V - V n V S - S V Cr - C r I m - n P V - P n C m V S C - V S4 S - 3 I R V - Fgure Mde I In he Analyss f Asymmerc Half-brdge Buck Cnverer The secnd nducr acs as an nducance makng p and wh S 4 pen, 4. p 4 Examnng Fgure 3.3.9, he vlages acrss he nducrs can be wren as; v v v 3 V nv V n V Cr v V V V n n V n V n V n V V The currens hrugh he magnezng nducances are gven by; 54

68 m m P m m n m m m m I V n V I V n Where: and are he nal cndns f he frs and secnd magnezng nducances respecvely. m I I m The curren hrugh S 3 s 3 P n The curren hrugh he blckng capacr C r, and he upu capacr curren C are gven as; m C m I 3 Mde II : - S S S 3 S 4 OFF OFF ON OFF S4 ON Fgure 3.3. Mde II In he Analyss f Asymmerc Half-brdge Buck Cnverer 55

69 In hs mde, S and S 3 are urned ff and befre urnng n S 4 ; he bdy dde f S 4 cnducs n hs mde fr a shr perd f me and s n shwn n wavefrms, allwng acheve ZVS fr S 4. Then, when S and S 4 are urned n wh ZVS fr S 4, we ener mde II. Mde II: : - T: S S S 3 S 4 OFF ON OFF ON Fgure 3.3. Mde II In he Analyss f Asymmerc Half-brdge Buck Cnverer The frs nducr acs as an nducance makng p and wh S 3 pen, 3. 3 P Examnng Fgure 3.3., he vlages acrss he nducrs can be wren as; v v v 4 V n V V Cr v V V V nv V n n nv V 56

70 The currens hrugh he magnezng nducances are gven by; m m P m m n m m m m V n V V n We can ne ha bh magnezng currens reversed her slpe drecn, where m was negave and nw s ramped up wh a psve slpe. The same apples n m bu n he ppse drecn. 4 P n The curren hrugh he blckng capacr C r, and he upu capacr curren C are gven as; m C m I 4 The cycle repeas, and llusrae he ZVS fr S 3 swch, anher half cycle s dscussed belw. Mde I : 3 : S S S 3 S 4 OFF OFF OFF S3 ON ON 57

71 Fgure 3.3. Mde I In he Analyss f Asymmerc Half-brdge Buck Cnverer In hs mde, S s urned ff, and befre urnng n S 3, he bdy dde f S 3 cnducs. Ths mde shuld be shr and s n shwn n he wavefrms, as he bdy dde cnducn lsses are hgh allwng acheve ZVS fr S 3. Then when S and S 3 are urned n wh ZVS fr S 3, he cycle s repeaed, and we ener mde I agan. As a summary f he vlage and curren sresses acrss and hrugh he swches, Table 3.3. shws he vlages acrss he swches durng urn ff and he curren hrugh he swches whle cnducng. Table 3.3. Vlage and Curren Sress Analyss fr he Asymmerc HBBC Mde I Mde II V.S. I.S. V.S. I.S. S m V n S V n - m S 3 3 V n /n S 4 V n -/n 4 58

72 The fcus f hs wrk n cenered n symmerc cnrl fr he benef ffers f dencal ransfrmer desgn, whch faclaes he magnec desgn. I s clear frm he abve dscussn ha he asymmerc half-brdge wll need dfferen magnezng nducances cmpensae fr he dfference n he perd durng whch hey sre energy. Ths wll cmplcae he analyss and s subjec fuure nvesgan. uy Cycle Shf CS s anher aracve cnrl scheme n whch Zer Vlage Swchng can be acheved n S and S, whch furher reduces he swchng lsses and ncreases effcency. Agan, hs cnrl scheme s n cvered n hs wrk and falls n he scpe f fuure analyss. 59

73 3.4 Smulan Resuls The HBBC crcu s smulaed and sme wavefrms are shwn n Fgures 3.4. and 3.4.: Fgure 3.4. Smulan Crcu fr a Symmerc HBBC The swchng sgnals v S, v S, v S3 and v S4 are shwn n Fgure 3.4. wh a small dead me allw ZVS fr S 3 and S 4 as explaned n he mdes f peran. 6

74 Fgure 3.4. Swchng Wavefrms Smulan Resul fr a Symmerc HBBC Sme her wavefrms f neres are as shwn n Fgure Fgure Smulan Resuls fr a Symmerc HBBC 6

75 3.5 Turns Ra vs. Effcency The mcrprcessr ndusry s mvng wards lwerng he upu vlage fr faser daa ransfer and lwer pwer cnsumpn geher wh ncreasng he curren and he pwer densy. The arge f he ndusry nw s feed he prcessr wh as lle as ne Vl. Buck-based cnverers have been he man buldng blck seppng he Vls npu he ne Vl needed a he prcessr sde. Mulphase buck was used furher decrease he upu rpple. The man drawback s he small duy cycle needed. Fr a buck cnverer: V V n In ur case: V n V and V V resulng n. 833 Ths small duy cycle prduces many prblems. The smaller he duy cycle, he hgher he curren peak s, and cnsequenly, he hgher he RMS values, whch resul n hgher cnducn lss. Added he abve cmes he urge fr achevng faser respnse whle decreasng he cnverer sze. Ths wll push n ncreasng he bandwdh and he swchng frequency, whch s always accmpaned by hgher swchng lsses. These requremens lw upu vlage, small sze and fas respnse resul n lwer effcency. Effrs are nw dedcaed and dreced wards ncreasng he duy cycle. Hence, ransfrmer-based buck cnverers have been a research pc fr slvng he abvemenned prblems. 6

76 In he half-brdge buck presened here, he upu vlage s a funcn f n nly he duy cycle and npu vlage, as n he case f he buck cnverer, bu als s a funcn f he urn ra n. V V n n A sudy n hw he urn ra affecs he effcency s shwn belw. Rearrangng he abve equan slve fr, we ge: V.. n V n Fr he same V a he npu sde and One Vl a he upu sde, he pmal value f s chsen as fllws. As shwn n Table 3.5., fr he same V npu and One Vl upu, varyng n we ge: Table 3.5. Turns Ra versus Effcency N Therefre, he HBBC mprves he duy cycle even wh urn and n lgh f he fac ha he upu vlage s mulpled by w; he duy cycle s ncreased by a facr f w. Examnng Table 3.5., s bvus ha he pmum urn ra n s n fr he fllwng reasns: The vlage sress acrss S 3 and S 4 wll be wce less han ha f a w-phase buck; hs wll allw he use f a lwer vlage MOSFET wh lwer R dsn and lwer lsses. Ths benef wll n be acheved f n was used. 63

77 ZVS fr S 3 and S 4 was acheved by applyng a small dead me whch was dable because was less han.5. Ths advanage wll n be pssble f n 3 were used and hgher values fr n wll n allw fr synchrnus drvng, herefre, n 3 was he maxmum urn ra n Table Small Sgnal Mdelng Crcu averagng has been appled he crcu ban he small sgnal mdel and desgn he cnrl lp. Afer perurban and lnearzan, he AC small sgnal mdel was derved as shwn n he fllwng equans: x Aavg x Bavg u A A3 A X B B3 B U d duy var an ne var an y Cavg x C C3 C X d duy var an ne var an Where; A, A, A 3 and A 4 are he sae marces f each mde f peran. Smlarly fr B, B, B 3 and B 4 snce B B 4 and he upu marces C, C, C 3 and C 4.and A avg, B avg and C avg are he average marces. The canncal frm was als derved as shwn n Fgure Fgure 3.6. The Canncal Equvalen Crcu 64

78 The ransfer funcns f neres are: G vd s Gd s s ω Q ω where: G vd s he upu duy cycle ransfer funcn. G d Vn n ω C m m and: Q R m C m Oupu mpedance can be expressed as: s Z // Z Z u where: m Z ω m 4 and: Z R ω R C The cmpensar was desgned and he resuls are shwn n Fgure

79 Fgure 3.6. p and Cmpensaed Sysem Frequency Respnse Fgure 3.6. shws he lp ransfer funcn and he cmpensaed n whch he cnrl lp was desgned. 66

80 3.7 Chaper Recap In hs chaper, he Half-brdge Buck ransfrmer-based nn-slaed plgy was examned n deal, and he symmerc and asymmerc cnrl schemes were cmpared. Ths plgy ffers many advanages he VRM research feld, and he ransfrmer nrduced helped as a curren dubler, ncreasng he curren suppled he lad and hereby decreasng he vlage spkes a he upu enhance he ransen respnse. The sep-dwn urns ra helped n nly ncrease he duy cycle and cnsequenly avd all asscaed prblems. And als decreased he vlage acrss he swches; whch enabled he use f a lwer vlage MOSFET and n urn decreased lsses. In an analgus drecn, he curren s ncreased, whch helped decrease he upu capacance and saved space and cs. The w swches added - S 3 and S 4 - are zer vlage swched whch decreased swchng lsses and cnsequenly ncreased he effcency. 67

81 CHAPTER 4 MAGNETICS ESIGN AN EXPERMINTA RESUTS 4. Inrducn Magnec cmpnens are presen n alms all swch mde pwer supples SMPS. Ther purpse may vary dependng n he applcan. All flers cnan magnec cmpnens ha mus be desgned, and hse magnec-based flers are nevable amng SMPS. Smemes energy s needed be sred and recvered durng a ceran nerval f he swchng perd acheve resnan cndns fr zer swchng. These energy srage devces have be nducrs r flyback ransfrmers. Sme SMPS need slan r level cnversn, hence he need fr a ransfrmer ha s a purely magnec elemen. In summary, SMPS desgners need knw a grea deal abu he magnec realm be able effcenly desgn hese magnec elemens. Neverheless, her desgn s a bg challenge, especally a hgh swchng frequences n he sense ha her naural nnae parasc elemens are he cause f s many prblems: hgh lsses, hgh spkes, nse, ec., whch wll dramacally affec effcency [33, 39]. Farady, enz and Ampere are he hree crners n whch he cnsun f he magnec hery s based, and each cnrbued by sang a law ha s avalable n alms all magnec bks. 68

82 dφ Accrdng Faraday s, he al flux change, n a wndng r a cnducr d lp nduces vlage n he wre [39]. dφ v d Whereas, enz declares ha he abve menned vlage s nduced wh a ceran plary ha, when dvded by he mpedance f he lp, wll n urn drve a curren ppse he rgnal flux [39]. Ampere saes ha he al curren passng hrugh he nerr f a pah s equal he ne magnemve frce, MMF, arund he clsed pah [39]. These hree laws gvern he magnec wrld. An undersandng f he magnec feld and cmpnens wll help pmally desgn any nducr r ransfrmer. Snce all nducrs and ransfrmers are merely cpper wndngs n magnec cres, an nsgh n he cre characerscs and prperes, geher wh dealed cmprehensn f he mehds f wndng, wll asss n a mre rbus desgn and hgher effcency. 4. Prperes and Characerscs f Magnec Cres Physcs ells us ha any curren-carryng cnducr wll prduce magnec feld r equpneals perpendcular he cnducr. If hs cnducr s placed n a magnec cre, hen hs feld wll be cnaned n hs cre. Cres are he medum n whch he magnec flux s ransferred frm ne par anher wheher magnec r elecrc [34]. Ideal ransfrmers d n sre energy. Raher, hey ransfer pwer frm ne prmary magnec sde he her r mulple secndary magnec sdes. Prmary and secndary wndngs are lnked va a magnec cre, and cres are n energy srage meda by any means. Energy s sred n wha s called and nennally creaed 69

83 magnezng nducance. Ideal ransfrmers have deally nfne magnezng nducance and zer magnezng curren, whch s why hey d n sre energy. Magnezng nducance s creaed by addng a nn-magnec maeral n he cre. Ar gaps are he nn-magnec srage meda, whch are added creae he magnezng nducances n whch energy s sred. The equvalen crcu f he ransfrmer shws ha he magnezng nducance s n parallel wh he deal ransfrmer, and herefre adds ar gaps ha decrease he nducance value f he ransfrmer [34]. Fgure 4.. Transfrmer Equvalen Crcu Cres have a specfc measure f hw magnec her magnec maeral s, and hs quany s refleced by her permeably. The hgher he magnec permeably, he gher he cuplng s, and hs means he al flux prduced a ne sde s fully ransferred hrugh he cre he her sde. Hgher permeably means less leakage [39]. Magnec permeably f cres s gven he Greek symbl µ. Ar gaps are anher channel fr flux, and her permeably s f free space and s gven he symbl µ. Where: µ 4π. -7 and µ >> µ µ s hghly dependen n emperaure [39]. 7

84 The nducance, n an deal ransfrmer, s drecly prprnal µ ; n A l m c µ [39]. Where: n s he number f urns f he wndng. A c and l m are he cre gemercal area and lengh respecvely. In he case when ar gap s added, he nducance value becmes: n R c R g [39]. Where: R s he relucance. lc R c and A µ c R g l g A µ [39]. c I s bvus ha when ar gap s added, he nducance value wll be less affeced n he emperaure-dependen µ. Cnsequenly, hs means here s a need fr mre sldly desgned nducance ha s ndependen f any varan n emperaure. Ar gaps als allw fr mre curren befre reachng sauran [39]. Inducrs and flyback ransfrmers sre energy n her magnezng nducances. Flyback ransfrmers are cnsdered nducrs wh mre han ne wndng r gapped ransfrmers [37]. T manan a ceran nducance value wh he presence f ar gaps, ne can eher ncrease he number f urns wh he radeff f ncreasng cupper lss and leakage nducance r use bgger cres wh cre ulzan n mnd. As a cnclusn, cres play an mpran rle n he desgn n addn prvdng flux channel. Undersandng he characerscs f cres s val fr beer desgn. 7

85 Magnec cre maerals nclude: - Meal Ally Tape-wund Cres [34, 39]: Applcan: bes used fr deal ransfrmers Examples: permally and amrphus meal ally cres Frequency range: lw, 5 6 and 4 Hz applcans Prperes: hgh permeably and hgh sauran flux densy rawback: lw cre ressvy Nes: a. w ressvy allws mre eddy currens flw n he cre, whch ncreases lsses. Ths can be allevaed by usng hn ape-wund lamnans b. Amrphus meal allys are he newer ape wund cres ha can be used n hgh frequency applcans. - Pwdered Meal Cres [34]: Applcan: bes fr nducrs and flyback ransfrmers Examples: pwdered rn, klm µ and permally pwder cres Frequency range: up khz Prperes: w permeably and hus hgher magnezng curren fr energy srage rawback: ssy cres, pwdered rn are he wrs amng hem, klm µ s beer and permally s he bes 7

86 Nes: fr applcan f khz frequency r less, pwdered meal cres wh her spread ar gap amng he cre parcles are beer han ferre cres wh he seres added ar gap due her hgher sauran lm. 3- Ferre Cres [34, 39]: Applcan: Ferres are ceramc maerals and are he ms ppular amng magnec cres fr dfferen applcans Examples: MnZn manganese and znc ferre cres and NZn Nckel and znc ferre cres Frequency range: up MHz Prperes: wer permeably and hgher ressvy hus less lsses ess expensve wh a wde varey f shapes rawback: ess rbus snce s ceramc wh less sauran lm Nes: Sauran s n cnsdered an ssue n hgh-frequency applcans, whch s he range n whch ferre cres are used. In summary, he cre maerals cmpared are shwn n Table 4... Table 4.. Cre Maeral Cmparsn Maeral usness Bsa Requred gap Ferre N lusy w scree Pwdered Irn usy Hgh srbued amng he parcles Kl-mu usy hgh amnaed meal usy hgh scree Cres have many lmans and lsses such as: cre lsses, wndw ulzan and sauran. ependng n he applcan and frequency range, cres are chsen 73

87 bes desgn and perae he crcu. Cre lsses are he man cncern n hgh frequency applcans, whereas sauran s n a prblem. Cre sauran s an ssue n lw frequency applcan. Tape wund cres are bes used n lw frequency ranges fr ransfrmer purpses, bu hey are replaced by her less rbus cunerpars such as ferres fr hgher frequency applcans. Pwdered rn s n an pn due s hgh cre lsses and lw permeably [34]. Fr nducrs and flyback ransfrmers, gapped ape wund cres r lssy pwdered rn cres are used n lw frequency ranges, whch gve cred her hgh sauran lms and neglec AC cre lsses a hs lw range. Agan, ferres uperfrm hem n hgh frequency ranges, where hgh cre lsses cme play and sauran seback dmnshes [34]. 4.3 sses 4.3. Cre and Hyseress sses Cre lss s manly hyseress lss a lw frequences, and a hgher frequences eddy curren lss verakes hyseress lss Eddy Curren sses As pned u abve, magnec cres are made f rn allys, whch unfrunaely have sme ressance. The nduced vlage acrss he wndng s als appled acrss he cre, and dvdng hs vlage by he cre mpedance wll resul n eddy curren flwng n he cre, whch s ranslaed lsses. Thus, eddy curren lsses 74

88 are funcn f he vls/urn dφ appled he wndngs and he duy cycle and s d ndrecly ndependen f he frequency [34, 39]. Eddy curren lsses are neglgble n he hgh ressance ferre cres and avded n he lw-ressance ape-wund cres when he lamnan mehd s appled. amnang he wndngs decreases he crss secn area, whch decreases he vlage nduced whn he cre and hus furher reduces he eddy curren lsses [34, 39] Skn Effec Cnducrs are represened by nducrs and ressrs as shwn n Fgure Fgure 4.3. Effec f Skn eph The dfference beween w currens, ne passng a he surface f he cnducr and he her ne passng n he cener f he cnducr, s he ressance. In ur case, he cnducr under sudy s he cre, and a hgher ressance cres means less eddy currens and herefre less lsses. A lw frequency, he nducr mpedance s lw, allwng he curren be equally dvded as passes hrugh he cener f he cre. Wh hgher frequency, he mpedance f he nducr ncreases, shfng he curren flw he surface where skn deph becmes an ssue [34, 35]. 75

89 Sld cres may cause he flux be n he surface f he cre, whch ncreases eddy curren lsses, hence he mprance f calculang he cre peneran skn effec [34, 35]: PEN ρ πµ µ f r I s drecly prprnal he square r f he ressvy ρ, dvded by frequency. A he same frequency, skn effec s n a prblem n hgh ressvy ferre cres. Bu s an ssue a hgher frequences [34, 35]. 4.4 Wndngs An effcen magnec desgn shuld ake n cnsderan many f he prblems and rs f all lsses, such as he dc ressance f he cpper, he cre characerscs and he leakage nducance, name a few. Cpper lss f he wndng can be, n sragh frward mehd, expressed as [39]: p cu _ lss I rms R cu Where: R cu s he cupper dc ressance and s equal : R cu l ρ A w w Where: l w and A w are he lengh and crss-secnal area f he wre. ρ s he ressvy f cpper and s equal.74x -6 Ω-cm. As llusraed n he prevus secn, cre maerals and prperes have a srng mpac n he magnec desgn. Wndng s anher val pc be regarded and wll be dscussed n hs secn. 76

90 A few man rules cme n handy n he area f magnec desgn. The frs rule s ha he wre dameer shuld be.5 mes he skn deph. The secnd rule s cpper wndngs shuld be peraed a curren denses f arund 4 4.5A/ mm. If he frequency s shfed hgher values, curren denses may ncrease as well. Wndw shape and sze affec ulzan and lsses and bh a wder wndw as well as nerleaved wndng n urn wll decrease eddy currens and leakage nducances. Bu he prce pad s hgher capacance beween wndngs. In her wrds, mehds adped decrease eddy currens and leakage nducance, whch nclude usng a wder wndw, nerleavng wndngs and small spacng beween he prmary and he secndary sdes, wll lead n hgher capacance [35]. 4.5 Expermenal Resuls The plgy dscussed n he prevus chaper s hghly sensve any leakage nducance, hus he magnec desgn shuld be rbus and ghly cupled decrease he leakage. A Maxwell smulan was used cmpare w ransfrmers. The frs ransfrmer was wnded usng PC44EE6-Z cres and wsed wres f.mm hckness avd skn deph. mm wre n dameer wh sx urns made up he prmary sde and s wce he hckness, and hree urns wre made up he secndary. Fgure 4.5. shws he ransfrmer. 77

91 Fgure 4.5. PC44EE6-Z Transfrmer The ransfrmer was mdeled and smulaed usng a Maxwell magnesacc smulan, and he mdel and smulan resuls are shwn n Fgures 4.5. and Fgure 4.5. PC44EE6-Z Transfrmer Mdel Fgure PC44EE6-Z Transfrmer Smulan 78

92 As shwn frm Fgure 4.5.3, he cre was sauraed, and herefre hs ransfrmer culd n be used. Added he abve, he ransfrmer ffered.7 cuplng a maxmum, makng a hgh leakage and sauraed cre. The crcu was bul and esed, and Fgure shws he prype. Fgure Prype # wh PC44EE6-Z Transfrmer The wavefrms baned frm he prype n Fgure are shwn n Fgure

93 Fgure Expermenal Resuls Usng PC44EE6-Z The magnezng curren and upu vlage rpples are n acceped, and anher ransfrmer was bul and esed. The secnd ransfrmer was a planar ransfrmer reduce he leakage. A PC95ET8/7.3Z cre was used wh w wndngs a he prmary sde and ne a he secndary sde as shwn n Fgure Fgure PC95ET8/7.3Z Transfrmer The ransfrmer mdel and smulan resuls are shwn n Fgures and

94 Fgure PC95ET8/7.3Z Transfrmer Mdel Fgure PC95ET8/7.3Z Transfrmer Smulan The measured leakage was.9, whch s beer han he prevus ransfrmer, bu he plgy was sll sensve. Crcu smulan shwed ha.96 cuplng was needed as a mnmum, and hus a small snubber was added wh he planar ransfrmer muned n a new bard as shwn n Fgure The expermenal wavefrms n Fgure 4.5. were as fllws. 8

95 Fgure Prype # wh PC95ET8/7.3Z Transfrmer Fgure 4.5. Expermenal Resuls Usng PC95ET8/7.3Z As shwn frm he wavefrms abve, he curren rpple was less han befre, bu he upu vlage sll experenced a lwer value due he lsses added by he snubber. 8

96 4.6 Chaper Recap Ths chaper fcused n he echncal ssues f he prype, and he frs par dscussed sme mpran magnec ssues and desgn. The secnd par was he expermenal aspec. Tw ransfrmers were bul, smulaed and muned n prype bards, and wavefrms were examned. The frs wnded ransfrmer had lw cuplng, hgh leakage, and smulan shwed ha he cre was sauraed. A planar ransfrmer was nvesgaed, bul, smulaed and esed. In bh cases, a prype was bul fr each ransfrmer, and he fllwng cmpnens were als used: IS 6558 cnrller IS 66 drvers IR376, Vls MOSFETS fr he lw sde swches: S 3 and S 4. IRR 7843, 3 Vls MOSFETS fr he hgh sde swches: S and S. The plgy shwed clear dependency n leakage, and a sld and ghly desgned ransfrmer s needed, where nerleavng mullayered negraed magnecs ffer a slun fr hs leakage dependency. 83

97 CHAPTER 5 MUTIPHASE BUCK 5. Inrducn Vlage Regular Mdules were based n seppng he npu vlage dwn a desred upu level. Hence, sngle cnvennal Buck cnverers, shwn n Fgure 5.., are he buldng blck f any VRM [3]. Cnvennal synchrnus Buck-based VRMs suffer he rade ff beween ransen respnse and effcency. Fr faser ransen respnse, smaller nducance s needed, whch ncreases he curren rpple and cnsequenly decreases effcency. Hgher fler nducances wll decrease curren rpple. Neverheless, wll lm he dynamc respnse f he cnverer [43]. Numerus upu capacrs were needed smh u he upu vlage spkes, whch k a l f he avalable space n he mherbard and ncreased he cs. Fgure 5.. Sngle Phase Buck Cnverer Many effrs were dedcaed lwer he upu capacrs and push he swchng frequency n hgher ranges. 84

98 The lad vares wh hgh slew raes, whch need he capacrs supply he lad n all cases wh he apprprae necessary curren as fas as pssble reduce any unwaned hgh spkes. Many have addressed he ssue f quanvely specfyng he upu spkes n rder sudy he effec f he upu capacrs n he verall sysem [43]. The space n he mherbard was alms fully ccuped, wh he flerng capacrs ncreasng he prce and resrcng he ransen respnse. The effec f addng mre capacrs wll be lmed by he nducance f he race [5]. Mehds fr decreasng hse capacr flers and ncreasng he ransen respnse whle mananng lw curren rpple and hgh effcency were nvesgaed cnnuusly. Mulphase buck was ne bg sep n he gal f decreasng he curren rpple wh nerleavng phases and swchng peaks smh u he al upu curren rpple [6, 4, and 4]. Inerleavng effcenly decreased he curren rpple, whch allwed fr smaller nducances be used enhance he ransen respnse. The smaller he curren rpples are hen he smaller he upu vlage spkes wll be. And he less he fler capacrs are needed, he less he prce wll be. Therefre, nerleavng became alms nevable n VRM sysems. Fgure 5.. shws a cnvennal mulphase buck cnverer. 85

99 Fgure 5.. Cnvennal Mulphase Buck Cnverer Wh he curren rpple reducn, whch nerleavng ffered, he use f smaller nducance became very benefcal fr hgh slew rae currens and faser dynamcs, allwng fr less upu capacrs mee he ransen requremens. In summary, mulphase cnverers n nly helped he curren rpple mprve, bu cnsequenly led upu capacr reducn. Als, paved he way fr hgher swchng frequences cme n play wh all her accmpanyng advanages ncludng lwerng he nducance and bsng he ransen respnse [3, 44]. The benefs f usng mulphase buck are n ffered fr free. Fr curren rpples be cancelled, narrw duy cycles are needed, whch harms he effcency grealy as shwn n Fgure I can be ned ha seppng he vlage frm Vls dwn ne Vl mpses a very small duy cycle. 86

100 Fgure 5..3 The Tp Swch Curren and uy Cycle Relan Ths prblem n nly naed pmzan need n cnverer peran bu als released anher mpran research feld n devce pmzan. As clearly deermned frm Fgure 5..3, he swchng lsses n he upper swch are mre severe han he cnducn lsses, whereas he ppse scenar apples n he lwer swch. Ths dcaes he need fr a lw R dsn swch a he bm swch and a small gae capacance devce a he p swch. Effrs are pu n ha fled f devce pmzan [44]. Thrugh analyss and sudes hghlgh he mpac f hgher bandwdh acheve faser ransen respnse, and her sudes shw he mprance f upu mpedance as anher aspec. In a smlar analgy, ncreasng he upu capacr wll be lmed by he nducance f he race and wll n furher help decrease he vlage spkes. In a parallel and equvalen lgc, ncreasng he nducance value wll face a hreshld beynd whch smaller nducance wll have n furher effec n eher he slew rae r he ransen respnse as lng as he cnrl lp bandwdh s cnsan [5]. 87

101 5. Cnvennal Mulphase Buck A buck cnverer s he man buldng blck f any VRM. I s he smples dc-dc cnverer fund n all mherbards, and seps he vlage dwn frm Vls nearly ne Vl fr mcrprcessr applcans. T sar wh, le us nvesgae he well knwn sngle phase buck, whch s shwn n Fgure 5.. wh s drvng and key wavefrms. S T - S Vn-V V V I Imax Imn a T T b Fgure 5.. Sngle Phase Buck a Crcu and b Swchng and Inducr Wavefrms As already avalable n leraure, hs cnverer peraes n w mdes. Mde I: Vn V I _ T I mn Mde II: V I _ T I max 88

102 Wh s mnmum and maxmum values as: I mn Vn R T I max Vn R T And average curren: I I mn max I _ avg I R V Vn R A mulphase buck cnverer verrdes s cunerpar sngle phase fr he benefs f reducng he upu curren rpple values ha allw he use f smaller nducance values and hence ncrease he ransen respnse. Cnvennal mulphase has he fllwng characerscs: Same V n Same nducance Therefre, he same slpes fr I Fr rpple cancellan: V *V n Where /n And n s he number f phases 89

103 Shwn n Fgure 5.. s he cnvennal mulphase crcu wh s drvng and mpran wavefrms. - - a b Where x T/ Fgure 5.. Cnvennal Mulphase Phase Buck a Crcu and b Key Wavefrms Cnvennal mulphase buck s explaned n leraure, and n cncep, mulphase buck s merely a repen f a sngle-phase buck wh 36 /n phase shf, where n n he 9

104 number f phases. Therefre, fr he abve w-phase buck, he fllwng equans can be easly derved: I max And I mn V V I n V V I n T T Smlarly, fr he secnd phase we have: I max And I mn V V I n V V I n T T Each phase carres half he upu vlage, hence he symmery. Inel has prpsed a new, mdfed mulphase-buck, where he npu vlages are n he same, and he duy cycle f each phase s dfferen accrdngly. ue he resulng asymmery, each phase wll carry a dfferen prn f he upu curren [45]. In he cnvennal mulphase buck cnverer, each phase wll carry an average curren equal I /n. where: I s he average upu curren and n s he number f phases. 9

105 In he fllwng nn-cnvennal mulphase buck, each phase wll carry an average curren equal I n_avg /I. where: I n_avg s he nducr average curren f each phase, and I s he average upu curren. In her wrds, fr a w-phase nn-cnvennal mulphase buck, he frs phase carres an average curren f I _avg /I, and he secnd phase carres he res whch s equal I _avg /I. We can defne k n be he ra f each phase average curren he al upu curren,.e. k I _avg /I and k I _avg /I r I _avg k I and I _avg k I where: k k In Fgures 5..3 and 5..4, he crcu and drvng sgnals are shwn. - - Fgure 5..3 Mul-Inpu Mulphase Phase Buck Crcu Cnfguran 9

106 Fgure 5..4 Mul-Inpu Mulphase Phase Buck rvng Wavefrms Where: x T and T y The general wavefrms are shwn n Fgure

107 Fgure 5..5 Mul-Inpu Mulphase Phase Buck Key Wavefrms 94

108 The fllwng expressns were derved and wll be used n he subsequen analyss. I max k I V V n T Where: k I /I. and I mn k I V V n T Smlarly, fr he secnd phase we have; I max k I V V n T I mn k I /I -k k I V n V T and I I mn I max The average nducr curren n each phase s: I I max mn I _ avg k and I max mn I _ avg k I I s als knwn ha: I I I _ max I _ mn I _ max I _ mn V I _ avg I _ avg I R Frm whch we can sae ha: 95

109 k, I _ avg I _ avg k I I _ avg _ avg 5.3 Seady-Sae Analyss s Phase: 5.3. Gan Equan Fgure 5.3. Phase One rvng and Inducr Wavefrms The average npu energy s gven by; n T V E n n d Subsung he npu curren f he s phase we ge; V n T V n V I mn d 96

110 E n T k I Vn nd Phase: Fgure 5.3. Phase Tw rvng and Inducr Wavefrms The average npu energy f he nd phase s gven by; y V E n x n n d Examnng Fgure 5.3., he average f he wavefrm can be wren as; V n * area f he rapezd Subsung he area f he rapezd frm Fgure 5.3. we ge; V n * b h h / V n T I I mn max The average npu energy f he nd phase can be wren by; E n Vn T k I 97

111 The al average npu energy s: E E E Subsung fr E n and E n we ge; n n n E E n n V n T I T k I V k V k n V n T k n I And he average upu energy s: E V I T Equang he ermnal energy sasfyng energy balance we ge: E V E I n T T I V k V n n k The vlage gan can be wren as; V V k V n n k 5.3. Rpple Calculan T sudy he benef f hs new cnverer he rpple s calculaed. Frm Fgure he rpple equan can be derved n a sraghfrward manner: b a Fgure Mul-Inpu Mulphase Cnverer a Crcu and b rvng Sgnals 98

112 Frm he wavefrms shwn n Fgure 5.3.3, he nducrs currens can be wren as: The nducr curren n he s phase can be wren as; < < < < T T T T V T T T T V T T T T V T I V V n mn Where: and max I T mn I T And max T V V I k I n, mn T V V I k I n The nducr curren n he nd phase s: < < < < T T T T V T T T T V V T T T T V T I V n Where: mn I T and max I T max mn I I I 99

113 And max T V V I k I n, mn T V V I k I n The al nducr curren s expressed as Subsung fr and we ge; < < < < T T T T T V T T T T T V V V n T T T T T V T I I V V V n mn The al curren rpple n he nducr curren s defned by; T T I Subsung he abve values, he rpple equan can be wren, afer mahemacal manpulan, as: T V V V I n Equang he end f he al curren, and mananng vl-balance, we ge: T where: _ mn I I and _ mn I I T V I I T V T We ge: T V T V I I

114 Vn V We knw ha: I T Vn V and I T We end up wh: V V V V n n Frm he gan equan, we ge: V V k V we ge afer equan manpulan. V n Vn and he fac ha k k, n n k secn. Engagng he abve resuls n a MahCA shee we ge he analyss n he nex Analyss Cnsderng an example wh he fllwng desgn specfcans: V V n n V 8V.87.5 k V f.3 sw.5v 3kHz uh I.45uH We ge he fllwng wavefrms shwn n Fgures 5.3.4, and

115 Fgure Inducr Curren n Phase f a Tw-Inpu Tw-Phase Cnverer Fgure Inducr Curren n Phase f a Tw-Inpu Tw-Phase Cnverer 3,,, Fgure Tal Inducrs Curren n a Tw-Inpu Tw-Phase Cnverer

116 5.4 Small Sgnal Mdelng Crcal lads such as mcrprcessrs need have a well-regulaed, ghly mananed cnsan vlage regardless f he npu r upu varans n npu vlage r upu lad. These varans are a physcal behavr ha needs be mahemacally quanfed n rder sudy her effec n he upu vlage and ry and regulae hem. Mdelng s a mahemacal descrpn f physcal acves based upn whch a sld cnrl desgn can be acheved hrugh a deep undersandng f he relan beween hse varans and he desred cnsan upu vlage by fcusng n prevalng acns and gnrng small nn dmnan behavr,.e., neglecng hgh frequency cmpnens and swchng harmncs n urn wll smplfy he desgn bu, n he her hand, wll gve mssng daa. Averagng s he mahemacal l ha smhes u rpple and harmnc swchng, hus averagng wll be he adped apprach. Ths averagng echnque creaes a se f nn-lnear dfferenal equans whch need be lnearzed befre applyng cnrl hery by he means f small sgnal mdelng. T derve he small sgnal mdelng, we care abu he energy srage elemens n he crcu, whch are w nducrs and a flerng capacr; Fr he w nducrs, we have he vlage acrss hem accrdng he wavefrms shwn n Fgure

117 S T T S 3 S S 4 V n-v V -V a V n-v V -V T x y T b Fgure 5.4. Mul-Inpu Tw-Phase Buck a Crcu and b Inducr Vlages Where: x / and y / T T The vlages acrss he nducrs and he curren hrugh he capacr can be wren as fllws: d d vn v T v T T / v T / v T / T T / 4

118 T T v T T v v T T v T v d d n / / / / T T R v T T R v T T R v T R v d dv C C / / / / The abve resuls can be resaed n each mde f peran as sae space represenan n he fllwng frms. urng he frs mde f peran: T v v v R d dv d d d d C n n B C A C urng he secnd mde f peran: / T v v v R d dv d d d d C n n B C A C

119 urng he hrd mde f peran: T v v v R d dv d d d d C n n B C A C urng he frh mde f peran: / 4 4 T v v v R d dv d d d d C n n B C A C The upu vecrs are he w npu currens, whch are shwn n Fgure 5.4.: b a Fgure 5.4. Inpu Curren n a Phase One b Phase Tw 6

120 The upu sae space vecrs are he w npu currens and can be easly shwn be he w fllwng sae space frms. urng he frs mde f peran: T v C C n n 443 urng he secnd mde f peran: / T v C C n n 443 urng he hrd mde f peran: T v C C n n urng he frh mde f peran: / 4 T v C C n n 443 The average sae spaces marces can be calculaed frm he abve as fllws; / / 4 3 A A A A A avg / / 4 3 B B B B B avg / / 4 3 C C C C C avg 7

121 The resuls are summarzed as: A avg R B C avg avg The resul f perurban and lnearzan s: x Aavg x Bavg u A 4 A 4444 X B 4 B 4444 U d 3 4 A3 A 4444 X B B U 4 d duyvar an duy var an ne var an y Cavg x duyvar an C C X d C C X 3 d duy var an ne var an herefre, he small sgnal mdelng equans f he energy srage, devces can be wren as fllws. d v vn Vn d d d v vn Vn d d C d vc d n v R The upu equans are: n ki d n ki d 8

122 Transfrmng he equans n small sgnal mdelng equvalen crcus wll resul n he crcus shwn n Fgures 5.4.3, 5.4.4, 5.4.5, and n Fgure Inpu Curren f he Frs Phase n - v n k I d Fgure Inpu Curren f he Secnd Phase V n d - - v n - - v Fgure Energy Srage Elemen Number nducr n he frs phase 9

123 - d V n v v n - - Fgure Energy Srage Elemen Number nducr n he secnd phase Fgure Energy Srage Elemen Number 3 upu fler capacr Frm he perurbed equans, we ge he ransfer funcns. Oupu vlage npu vlage : ] [ n R R s R C s s R v v Oupu vlage npu vlage : ] [ n R R s R C s s R v v Oupu vlage duy cycle : n R R s R C s R V d v

124 Oupu vlage duy cycle : v d R V n s CR s R R rawng he duy cycle ransfer funcn; v Renamng: G d d And v d G d Fr he fllwng specfcans: V n V, V V, f sw 3kHz, V n 5V, I 6A,.7uH,.83,.57uH,. We ge he fllwng Bde pl shwn n Fgure 5.4.8: Fgure Bde Pl f a Tw-Inpu Tw-Phase Buck Cnverer