A Tunable Butterworth Low-Pass Filter with Digitally Controlled DDCC

Transcription

1 ADOENGNEENG, VO., NO., JUNE 3 5 A Tunble Butterworth ow-p Flter wth Dgtlly Controlled DDCC Yuh-Shyn HWANG, An U, Sn-Fu WANG, Su-Che YANG, Jnn-Jong CHEN Deprtment of Electronc Engneerng, Ntonl Tpe Unverty of Technology, Tpe 6, Twn Deprtment of Electronc Engneerng, Mng Ch Unverty of Technology, Tpe 43, Twn yhwng@ntut.edu.tw, lun@ju.edu.tw, f_wng@ml.mcut.edu.tw, henry3@hotml.com, jjchen@ntut.edu.tw Abtrct. Th pper preent 6 th -order tunble Butterworth low-p ctve flter wth Dgtlly Controlled Dfferentl Dfference Current Conveyor (DDCC). Th ctve flter ynthezed ung the ytemtc method of voltge-mode lner trnformton (VMT) whch enble the flter to ue fewer ctve component, grounded cpctor nd grounded retor to vod the prtcl effect. The bndwdth of the flter cn be tuned by dgtl wtche to djut the output current of the DDCC. The pecfcton of the flter re bed on 3G tndrd, nd the flter controlled by 8-bt dgtl gnl. The tunble bndwdth of the flter from khz to.6 MHz. The flter chp lyout relzed by TSMC.8 μm CMOS P6M mxed-mode technology. The upply voltge.8 V nd the power conumpton 3.6 mw. Keyword Dfferentl dfference current conveyor (DDCC), voltge-mode lner trnformton (VMT), current dvon network (CDN), ctve flter.. ntroducton n recent yer, CMOS crcut hve become the mn buldng block of VS crcut. n nlog C degn, ctve flter hve been ued for communcton nd F front-end proceng uch chnnel electon flter [], []. There re mny method to yntheze hgh-order ctve flter [3], [4], [5]: Follow-the-leder feedbck, ccde ynthe, Bruton' trnformton, ctve nductor pproch, epfrog, ner trnformton, etc. Becue the lner trnformton method my be ppled to prevent monolthc ntegrted flter from the effect of unpredctble vrton of proce prmeter, t ppled n th tudy not only to mplfy the degn nd to reduce the number of component but lo to ue grounded cpctor nd retor to vod prtcl effect. The reult mple but effectve degn of hgh-order ctve flter. Secton dcue the bc theory of Voltge-Mode ner Trnformton (VMT), nd dgtlly controlled dfferentl dfference current conveyor (DDCC). The degn of n ctve flter nd the mplementton of the propoed flter re gven n Secton. The multon reult re hown n Secton V, nd the concluon re gven n Secton V.. The VMT nd the Dgtlly Controlled DDCC Th ecton expln the concept of the VMT nd the dgtlly controlled DDCC.. The VMT A conventonl ccded two-port network hown n Fg.. N V V V Fg.. N V A conventonl two-port network. The vrble of nput nd output re n the form of voltge nd current. The equton hown n (). V V A T C n V n B V D where T the trnfer mtrx. The vrble cn be chnged nto voltge vrble (x, x, y, y ) through the VMT method by the trnfer mtrce S nd S hown n () nd (3). x y x y S S V V V V Nn n V n (), (). (3) x j nd y j re voltge vrble, α j nd γ j re dmenonle, nd the unt of β j nd δ j mho; j =, nd =... n, where n the order of the two-port network.

2 5 Y. HWANG, A. U, S. WANG, S. YANG, J. CHEN, A TUNABE BUTTEWOTH OW-PASS FTE WTH (4) cn be derved from ()~(3): x x - A B - x STS y y C D - y b x. (4) c d y V V V DDCC The y j cn be repreented by the x j. f the x j repreent the nput nd the y j repreent the output, new ccded two-port ldder prototype network cn be developed. Equton (5) nd (6) re ntroduced to mply the nterconnecton between the two-port: Fg. 3. Symbol of DDCC. V DDCC S - S, (5) V V = x y x y. (6) Thee equton cn be clled the cro-ccded nterconnecton whch men tht the connecton croccded between every two of the new two-port network hown n Fg.. Vb Fg. 4. del model of DDCC. V=V-V M5A M5B M5C M5D M9 y y y y y n y n c N N Nn M MA MA M M3A M4A M3 M4 Cc Vout x x x x x n x n M8 Fg.. The cro-ccded two-port network fter VMT. M6 M7. The Dgtlly Controlled DDCC The ymbol of the DDCC [6], [7], [8] hown n Fg. 3. The DDCC n ctve component tht h four port mrked Y, Y, nd. The DDCC n ctve component whch bclly econd generton current conveyor combned wth dfferentl dfference mplfer. The mll gnl model of DDCC hown n Fg. 4. There re two type of DDCC. The reltonhp mong the vrble re = =, V = V - V nd = for the potve type of DDCC expreed by (7), or = =, V = V - V nd = - for the negtve type of DDCC, Y V V V We ue the DDCC confgurton propoed n [9] nd dd four current-hunt trntor MA, MA, M3A nd M4A t the nput tge, hown n Fg. 5. Such rrngement cn mprove the nput common mode rnge well enhnce the lnerty of the DDCC. The component prmeter of the propoed DDCC re lted n Tb.. Y (7) Fg. 5. The chemtc of the DDCC. Trntor (DDCC) Sze (W/), μm M5A, M5B, M5C, M5D /.5 M, M, M3, M4 48/.5 MA, MA, M3A, M4A /.5 M6, M7 6/.5 M8, M9 6./.5, 3.4/.5 etor nd Cpctor etor (C) Cpctor (CC) Vlue kω.5 pf Tb.. The component prmeter of the propoed DDCC. Current dvon network (CDN) []-[4] re dded n order to wden the rnge of the output current of the propoed DDCC. The CDN cn modfy the current reltonhp from = to = α for the potve type of DDCC nd = -α for the negtve type of DDCC, where the dgtl control fctor α the dgtl vlue correpondng to the CDN bnry wtche wth < α. Thu potve type dgtlly controlled DDCC cn be repreented by (8),

3 ADOENGNEENG, VO., NO., JUNE 3 53 VY Y VY. (8) V The block dgrm of 4-bt dgtlly controlled CDN hown n Fg. 6 whch cont of 4 current dvon cell (CDC). Accordng to the current dvon prncple, ech CDC h one nput current n nd three output current o, o nd o3. Ther reltonhp re expreed follow: n _ o _ d, (9) n _ o_ d, () n _ o3_ () where d the dgtl control bt of the th CDC. A lo hown n Fg. 6, the two output current o nd o of the 4- bt CDN re gven by nd, () 3 3 o o3_ o _ ( 4 d ) 3 3 o o_ ( 4 d ) n _3 n _3 (3) 3 ( ) 4 o d. (4) n _3 Hence the current gn of the 4-bt CDN controlled dgtlly. n_3 (=6o3_) CDC3 d3 d d d CDC CDC CDC n_ n_ n_ (n_3=o3_3) (n_=o3_) (n_=o3_) (n_=o3_) (o3_3) (o3_) (o3_) o_3 o_3 o_ o_ o_ o_ o_ o_ d3(n_3/) d3(n_3/) o Fg. 6. The block dgrm of 4-bt dgtlly controlled CDN. n th tudy, n 8-bt dgtlly controlled CDN dvded nto two uch 4-bt CDN, ech cpble of mrrorng nd huntng the current n the rto 6:8:4:, whch re determned by the W/ ze of the MOS trntor. The chemtc of the 8-bt dgtlly controlled CDN hown n Fg. 7. The current from the prevou tge re mrrored by M3 nd M8 whch re controlled by the mot gnfcnt (MSB) 4 bt nd the let gnfcnt (SB) 4 bt, repectvely. A explned bove, the current re dvded n the rto 6: determned by the W/ ze of M3 nd M8, nd ech of M3 nd M8 re connected to 8 MOS trntor wth pproprte W/ ze to hunt o o3_ the current n the rto 6:8:4:. The two current flow through M nd M6 repectvely nd fnlly merge the dgtlly controlled output current. The operton of the NMOS network re complementry to thoe of the PMOS network, nd the two current flow through M5 nd M6 to merge. The component prmeter of the CDN re lted n Tb.. Trntor (CDN) Sze (W/)μm M3(b), M3c(d), M3e(f), M3g(h) 3/.5, 6/.5, 8/.5, 4/.5 M9(b), M9c(d), M9e(f), M9g(h).8/,.4/, 5./,.6/ M8(b), M8c(d), M8e(f), M8g(h).4/.5, 5./.5,.6/.5,.3/.5 M34(b), M34c(d), M34e(f), M34g(h) 3./.4,.6/.4,.8/.4,.4/.4 Tb.. The component prmeter of the CDN. Fnlly, the DDCC nd the CDN re combned to form dgtlly controlled 8-bt DDCC. The ymbol of the dgtlly controlled 8-bt DDCC hown n Fg. 8, nd the full chemtc hown n Fg.9. n next ecton, we wll decrbe how VMT ppled to the degn of hgh order flter by the dgtlly controlled DDCC crcut. 3. The Degn of n Actve Flter To demontrte the effectvene nd the flexblty of the propoed degn, 6 th -order tunble Butterworth lowp ctve flter ung dgtlly controlled DDCC preented. The pplcton of lner trnformton nd the relzton of the flter ung dgtlly controlled DDCC re llutrted n th ecton. The pve prt of the flter dvded nto three dfferent porton: nput porton, output porton, nd mddle porton. The mddle porton further dvded nto ere wth α j = δ j = nd C hunt wth β j = γ j = to reduce the complexte of trnformton mtrce. Furthermore, we cn chooe ether α j or γ j = ±, nd ether β j or δ j = ± to reduce the number of the dgtlly controlled DDCC. Tke the 6 th -order Butterworth low-p ldder flter hown n Fg. for exmple. The trnformton mtrx of t nput porton (the -C hunt rm connected to the voltge ource) cn be expreed. (5) t output vrble x nd y cn be expreed x E y. (6) C The trnfer functon cn be derved for the dgtlly controlled DDCC crcut (-bed crcut) nd re lo hown n Tb. 3 by x E x E y C C. (7)

4 54 Y. HWANG, A. U, S. WANG, S. YANG, J. CHEN, A TUNABE BUTTEWOTH OW-PASS FTE WTH M3 M8 3 3b 3c 3d 3e 3f 3g 3h V3+ V3- V+ V- V+ V- V+ V- 9 9b 9c 9d 9e 9f 9g V3+ V3- V+ V- V+ V- V+ 9h V- M3 M3b M3c M3d M3e M3f M3g M3h M9 M9b M9c M9d M9e M9f M9g M9h Vp M4 M4b M4c Vp M Mb Mc M4c M5 M4c M V3 M3 M9c M36 M5 M6 M9c Vn M9 M9b M9c Vn M35 M35b M35c M8 M8b M8c M8d M8e M8f M8g M8h M34 M34b M34c M34d M34e M34f M34g M34h 8 8b 8c 8d 8e 8f 8g 8h V3+ V- V+ V- V+ V- V+ V b 34c 34d 34e 34f 34g 34h V3+ V- V+ V- V+ V- V+ V3- M7 M33 M M6 Fg. 7. The chemtc of the 8-bt dgtlly controlled CDN. Dgtlly controlled DDCC V V V Y Y DDCC± ± CDN ±α Fg. 8. The ymbol of the dgtlly controlled 8-bt DDCC. M3 M8 3 3b 3c 3d 3e 3f 3g 3h V3- V+ V- V+ V- V+ V3+ V- 9 9b 9c 9d 9e 9f 9g V3+ V3- V+ V- V+ V- V+ 9h V- M3 M3b M3c M3d M3e M3f M3g M3h M9 M9b M9c M9d M9e M9f M9g M9h Vp M4 M4b M4c Vp M Mb Mc Vb M5A M5B M5C M5D M9 M4c M5 M4c M c Vout V3 M MA MA M3A M4A M M3 M4 Cc M8 M3 M9c M36 M5 M6 M9c M6 M7 Vn M9 M9b M9c Vn M35 M35b M35c M8 M8b M8c M8h M8d M8e M8f M8g M34 M34b M34c M34d M34e M34f M34g M34h 8 8b 8c 8d 8e 8f 8g 8h V3- V3+ V- V+ V- V+ V- V b 34c 34d 34e 34f 34g 34h V3- V3+ V- V+ V- V+ V- V+ M7 M33 M M6 Fg. 9. The full chemtc of the dgtlly controlled 8-bt DDCC.

5 ADOENGNEENG, VO., NO., JUNE 3 55 The trnformton mtrx of the ere rm of the mddle porton =.(8) t cn be hown tht x x y y (9) t correpondng dgtlly controlled DDCC lole ntegrtor crcut cn lo be lted n Tb. 3 wth t trnfer functon x x x x y y ( ) C C. () The trnformton mtrx of the C hunt rm of the mddle porton =. () t cn be hown tht y y x x. () C t correpondng dgtlly controlled DDCC lole ntegrtor crcut cn lo be lted n Tb. 3 wth t trnfer functon y y x x ( C 3 x x ) C. (3) The trnformton mtrx of the output porton (the - ere rm) cn be expreed t cn be hown tht =. (4) x6 y V 6 O. (5) 6 t correpondng dgtlly controlled DDCC lole ntegrtor crcut cn be preented n Tb. 3 wth t trnfer functon y x x. (6) 6 6 ( ) V 6 O C C n ummry, we cn dvde the flter prototype nto x ecton nd chooe pproprte trnformton mtrce to obtn ther x-y domn trnfer functon. E E C 4 6 C 3 C 5 V o Fg.. The 6 th -order Butterworth low-p ldder flter. Pve flter ecton crcut C C Trnformton mtrx & trnfer functon x E C y x x y y y y x x C y x 6 V 6 O Tb. 3. The trnformton block. = - C = C b = C3 c = Dgtlly controlled DDCC-bed crcut & degn equton E x y x x x x x 6 C4 d C C C C C y C C y y y C y C V 6 O C = C5 e =Vo Fg.. A dgtlly controlled DDCC-bed 6 th -order tunble Butterworth low-p ctve flter. Then, we cn cro-ccde ther correpondng dgtlly controlled DDCC crcut to contruct the flter. A 6 th -order tunble Butterworth low-p ctve flter ung dgtlly controlled DDCC, grounded retor nd grounded cpctor preented n exmple n th tudy. n th flter, V DD =.8 V, = f 5.3 kω, = f = 5.3 k/α, b = e 7.3 k, c = d 9.9 k, C = C 6 = 6pF, nd C = C 3 = C 4 = C 5 = pf [5], [6]. t confgurton wth x dgtlly controlled DDCC hown n Fg.. f f C6

6 56 Y. HWANG, A. U, S. WANG, S. YANG, J. CHEN, A TUNABE BUTTEWOTH OW-PASS FTE WTH CDN 8-bt SW (α) () Bndwdth Output voltge (V P-P ) THD (%).6 MHz 6 mv.9-6.db (.5).5 MHz 8 mv.74 (.5) 68 khz 36 mv.69 (.5) 363 khz 6 mv.58 (.65) 87 khz 5 mv.57 (.35) 93. khz 35 mv.5 KHz~.6MHz (.565) (.785) 48.4 khz 65 mv khz 3 mv 5.35 Fg.. The multon frequency repone. (.3965) khz 36 mv 8.8 Tb. 4. The multon reult t n nput voltge of 6mV(V P-P ). Flter type Butterworth ctve low-p flter Order 6 Frequency nge khz ~.6 MHz pple db THD.9 MHz Voltge Supply.8 V Power Conumpton 3.6 mw Chp Sze mm (wthout PAD) Technology TSMC.8μm P6M mxed-mode proce Tb. 5. The pecfcton of the propoed flter. Fg. 3. The chp lyout of the propoed flter. 4. Smulton eult The propoed flter tuned by 8-bt CDN wtch (the dgtl control fctor α). Nne multon wth dfferent vlue of α re conducted t n nput voltge of 6 mv (pek-to-pek), nd the rnge of the tuned frequence from khz to.6 MHz. The multon reult re hown n Tb. 4 nd the frequency repone re hown n Fg.. The flter mplemented n TSMC.8 m P6M proce wth upply voltge =.8 V. The chp lyout hown n Fg. 3, nd the pecfcton of the flter re hown n Tb. 5. The chp re wthout PAD mm. 5. Concluon The degn of tunble dfferentl dfference current conveyor (DDCC) ctve flter ung voltge-mode lner trnformton (VMT) method preented. The bndwdth of uch flter cn be tuned by the α fctor (the dgtl vlue correpondng to the CDN bnry wtche) to djut the output current vlue of the DDCC. A 6 th -order tunble Butterworth low-p ctve flter wth dgtlly controlled DDCC fbrcted ung 6 dgtlly controlled DDCC long wth 6 grounded cpctor nd 8 grounded retor. t CDN crcut llow the bndwdth of the flter to be tuned by djutng the α fctor. The propoed flter h the followng mert: ey nd ytemtc degn procedure re vlble, ll cpctor nd retor re grounded, nd the equton re mple. Furthermore, the degn nd crcut cn be extended nd ppled to other pplcton. Acknowledgement The uthor would lke to thnk Ntonl Scence Councl (NSC) nd Chp mplementton Center (CC) of Twn for the fnncl nd techncl upport. eference [] AAHE, H. A., EWAN, H. O., SMA, M. A CMOS hghly lner chnnel-elect flter for 3G multtndrd ntegrted wrele recever. EEE Trncton on Sold-Stte Crcut,, vol. 37, no., p

7 ADOENGNEENG, VO., NO., JUNE 3 57 [] STEH, U., HENKE, F., DAUGE,., WADOW, P. A fully dfferentl CMOS ntegrted 4 th order reconfgurble GM-C lowp flter for moble communcton. n Proceedng of the th EEE nterntonl Conference on Electronc, Crcut nd Sytem. Shrjk (UAE), 3, p [3] HWANG, Y. S., CHEN, J. J., A, J. H., SHEU, P. W. Fully dfferentl current-mode thrd-order Butterworth VHF Gm-C flter n.8 m CMOS. EE Proceedng Crcut, Devce nd Sytem, 6, vol. 53, no. 6, p [4] A-HASHM, B. M., E, Y., WONSK, M. Anly of mrror mmtch nd clock-feedthrough n Bruton trnformton wtched current wve flter. EE Proceedng Crcut, Devce nd Sytem, 3, vol. 5, no., p [5] AS, N. D. M., SON, N. Development of ctve nductor n CMOS tunble F bndp flter. n Proceedng of the EEE egonl Sympoum on Mcro nd Nnoelectronc. Sbh (Mly),, p [6] MAHMOUD, S. A., HASHESH, M. A., SOMAN, A. M. owvoltge dgtlly controlled fully dfferentl current conveyor. EEE Trncton on Crcut nd Sytem : egulr Pper, 5, vol. 5, no., p [7] BAHM, M. A., MNAE, S., YUCE, E., HEENCSA, N., KOTON, J. oy/lole flotng/grounded nductnce multon ung one DDCC. doengneerng,, vol., no., p [8] KUMNGEN, M., TOTEANCHA, U, DEJHAN, K. Voltgecontrolled flotng retor ung DDCC. doengneerng,, vol., no., p [9] BAHM, M. A., KUNTMAN, H. Hgh lnerty CMOS dfferentl dfference current conveyor (DDCC). n Proceedng of the 4 th nterntonl Conference on Mcroelectronc. Berut (ebnon),, p [] E-ADAWY, A. A. A., SOMAN, A. M., EWAN, H. O. ow voltge dgtlly controlled CMOS current conveyor. AEU- nterntonl Journl of Electronc nd Communcton,, vol. 56, no. 3, p [] TANGSAT, W., PASETSOM, D., SUAKAMPONTON, W. ow-voltge dgtlly controlled current dfferencng buffered mplfer nd t pplcton. AEU - nterntonl Journl of Electronc nd Communcton, 9, vol. 63, no. 4, p [] TANGSAT, W., PUKKAANUN, T. Dgtlly progrmmble current follower nd t pplcton. AEU - nterntonl Journl of Electronc nd Communcton, 9, vol. 63, no. 5, p [3] BOEK, D., AH, A., JAKA, W., SPUCHYANUN, M., BAJE, J. elzton of electronclly tunble voltgemode/current-mode qudrture nuodl oclltor ung C-CG- CDBA. Mcroelectronc Journl,, vol. 4, no., p [4] TAM, T., SMA, M. Stttcl degn of bt current dvon network. Anlog ntegrted Crcut nd Sgnl Proceng,, vol. 9, no. 3, p [5] SCHAUMANN,., AO, H., MAC, V. V. Degn of Anlog Flter. nd ed. New York (USA): Oxford Unverty Pre, 9. [6] CHANG, C. M., EE, C. N., HOU, C.., HONG, J. W., TU, C. K. Hgh-order DDCC-bed generl mxed-mode unverl flter. EE Proceedng Crcut, Devce nd Sytem, 6, vol. 53, no. 5, p About Author... Yuh-Shyn HWANG w born n Tpe, Twn, n 966. He receved the Ph.D. degree from the Deprtment of Electrcl Engneerng, Ntonl Twn Unverty, Tpe, n 996. Durng nd 996 3, he w ecturer wth the Deprtment of Electrcl Engneerng, ee-mng nttute of Technology, New Tpe Cty, Twn nd n Aocte Profeor wth the Deprtment of Electrcl Engneerng, Hw H nttute of Technology, New Tpe Cty, Twn, repectvely. n 3, he joned the Deprtment of Electronc Engneerng nd the Grdute nttute of Computer nd Communcton Engneerng, Ntonl Tpe Unverty of Technology, Tpe, where he currently Full Profeor nd the Chrmn of the Deprtment of Electronc Engneerng. He joned the Edtorl Bord of Actve nd Pve Electronc Component n. H current reerch nteret nclude nlog ntegrted crcut, mxedgnl ntegrted crcut, power electronc ntegrted crcut, nd current-mode nlog gnl proceng. An U w born n Tpe, Twn,.O.C. n 97. He receved h M.S. degree n electronc engneerng from Ntonl Twn Unverty of Scence nd Technology (NTUST), Tpe, Twn,.O.C. n 996. He currently workng towrd h Ph.D. degree n the Deprtment of Electronc Engneerng nd nttute of Computer nd Communcton of Ntonl Tpe Unverty of Technology, Twn,.O.C. He h been wth St. John Unverty, New Tpe Cty, Twn nce 997, where he currently n ntructor n the Deprtment of Computer Scence nd nformton Engneerng. Sn-Fu WANG w born n Chnghu, Twn, n 976. He receved the M.S. nd Ph.D. degree from the Deprtment of Electronc Engneerng, nttute of Computer nd Communcton, Ntonl Tpe Unverty of Technology, Twn, n 3 nd, repectvely. He now n tnt profeor n the Deprtment of Electronc Engneerng, Mng Ch Unverty of Technology, Twn. H reerch nteret nclude network communcton ytem nd nlog ntegrted crcut. Su-Che YANG receved the M.S. degree from the Deprtment of Electronc Engneerng, nttute of Computer nd Communcton, Ntonl Tpe Unverty of Technology, Twn, n 8. H reerch nteret nclude nlog ntegrted crcut nd gnl proceng. Jnn-Jong CHEN w born n Keelong, Twn, n 966. He receved the M.S. nd Ph.D. degree n electrcl engneerng from Ntonl Twn Unverty, Tpe,.O.C., n 99 nd 995, repectvely. From 994 to 4, he w on the fculty of unghw Unverty of Scence nd Technology, Twn. Snce Augut 4, he h been wth the Deprtment of Electronc Engneerng, Ntonl Tpe Unverty of Technology, where he now Profeor. H reerch nteret re n the re of mxedgnl ntegrted crcut nd ytem for power mngement.