ứng dụng memristor để thiết kế mạch nhận dạng kí tự sử dụng bộ nhân tín hiệu

Tgp Chi Khoa Hpe Gido Due Ky Thugt (32/2015) Trudng Dgi Hpe SuPhgm Ky Thuat TR Hd ChiMinh ITNG DVNG MEMRISTOR DE THIET KE MACH NHAN DANG KI Tif StT DyNG BO NHAN TIN HIEU MEMRISTOR-BASED CHARACTER RECOGNITION USING SIGNAL MULTIPLICATOR Huynh Ho^ng Ha, V6 Minh Huan Trudng Dgi hoc Suphgm Ky Thugt TP.HCM Ngay toa scan nh$n bai 02/02/2015 phan bi§n danh gi^ 8/3/2015 chap nh$n dang 12/3/2015 TOM TAT Thiit ki mgch nhdn dgng ki tu ung dung memristor thong qua phep nhdn tin hiiu dugc trinh bay bdi bdo Mgch nhgn dgng su dung congXOR dugc thiit ke tic memristor Bdng each diiu khiin hogt dong cua memristor phu hop, ta se thu dugc dien dp ngd tuong ung vdi timg tap du lieu ngo vdo Dua vdo dien dp ngo va tap mdu du lieu co san, ta xdc dinh dugc ki tu cdn nhgn dgng Ddc biet, ngo dugc luu tr& cac phan hi memristor, khong bi mdt dir lieu cd ngung cdp nguon va du" lieu ngo cd the truy cap lai dugc sau Cdu trite mgch nhgn dgng ki tu co ung diing memristor giup tiit kiem dugc ndng lugng tieu hao, qud trinh xu ly nhanh vd mat tich hgp cao so ngo vdo cdng l&n Bai bao sii dung md hinh memristor ly tudng Tdt ca kdt qua nghiSn curu dugc md phdng bang cong cu Cadence Tir khda : memristor, congXOR, phep nhdn tin hieu, nhgn dgng ki tu ABSTRACT A character recognition based on memristor via resistive logic signal multiplication is introduced The integrated circuit uses seven memristor-based XOR gates and XOR gate is made by the combination of Memristors By controlling the memristor's operation suitably, we obtain the corresponding output voltage according to the inputs The interests of this circuit structure is the output registered in the nonvolatile memristors, so that the computed output can be stored without power supply and accessed anytime later This circuit structure saves energy, the processing speed is fast and the integration density is high for the large number of inputs The report mainly focuses on the model of ideal memristor All the simulation results are studied using Cadence tool Index Terms: memristor, XOR, signal multiplication, character recognition L G l l THIEU Viec xu ly thdng tin cang phirc tap ddi hdi cac he thdng tuong lai phai cd tich hgp cao hon, de vugt qua dugc gidi ban hien tai cua cdng nghe CMOS truyen thdng, cimg vdi gidi han ciia phuong phap "quang khde" Dinh luat Moore's Law cung dang ddn tiSn ddn gidi han cua mmh vi kha nang tich hgp cua cdng nghe CMOS la cd gidi han Dd dat dugc yeu cdu vd tich hgp cang cao, thi cac cong nghe, chdt lieu mdi cung da va dang dugc nghien ciiu nhigu vdi muc dich la thay thd duoc cdng nghe CMOS hien Cac thiet bi memristor[l], [2] hoat ddng nhu cac chuyen mach, cd kha nang dieu khien dugc bang dien ap ludng cue, da dugc sir dyng de xay dung len cac mach ban dan mat dd cao Ngoai ra, memristor cdn cd mot dac tinh quan nua la kha nang luu trii trang thai hd khang trudc do, ca ngung cdp ngudn cho mach Md kha nang ap dung cac thilt bj memristor vao cac bp nhd khdng bay hoi, cdng logic, FPGA vdi mat dp cao hon, quan trpng hon la cd kha nang thich nghi vdi cdng nghe CMOS [3], [4] Do dd, cac kien triic tinh Tgp Chi Khoa Hpe Gido Dge Ky Thugt (32/2015) Trudng Dgi Hpe Su Phgm Ky Thugt TR Hd ChiMinh toan nano dua tren memristors hiia hen se tao dugc cac ling dung tinh toan m$t dp cao va tieu thu cdng sudt thdp Cd rdt nhidu co hdi nghien ciru dugc md cho cdng nghe memristive (trd khang nhd) Vi du nhu eac ung dyng; bp nhd khdng bay hoi tich hgp mat dp cao, bd xir Iy tin hieu [5], synaptic neuromorphic networks [6] Dua vao cac bai bdo da nghien ciiu, bdi bdo ndy se gi&i thieu vi mgt kiin tnie tinh todn trd khdng nhd mat cao de nhgn dgng cdc ki tu thong qua muc dien dp ngo tinh toan dugc, dua tren nguyen ly cua bp nhan tin hieu co ban Trong nghien ciiu nay, thi bd nhan trd khang nhd se duge nhiing vao mach tieh hgp lai, gdm cd cac phan tir memristor trang thai va chuyen mach CMOS Mach nh^n dang ndy se difa tren nhieu cong logic XOR, dong vai tro nhw bp nhan trd khang, dugc kit noi v&i Cu the Id, mot day song song cdc cong XOR dugc ket hgp vdi di tinh todn cdc phep nhdn mdt each ddng thdi va dugc tdng hgp kdt qua d ngo ciia mach mach CO ban cdn thiSu, ben canh dien trd, cugn day va tu dien Memristor the hien mdi quan he giiia didn tich va tu thdng nhu hinh [8] Nhung den nam 2008, mdt nhdm nghien Cliu ciia R.Stanley Williams d phdng nghien Cliu HP mdi cdng bd su tdn tai ciia nguyen td mach Nguyen lieu chinh su dung xay dung memristor la mpt lop titan oxit mdng Khdng gidng nhu eac nguyen td co ban khac, memristor cd the thay ddi dugc tr^ng thai trd khang Ngay ca ngimg cung cap ngudn thi memristor van ghi nhd dugc lugng dien tich da ehay qua Neu su dung mdt ngudn dien ap nhd de dieu khien, thi chiing ho^t ddng nhu cac thiet bi m^ch tuong tu; nguge lai, neu sir dung ngudn dien ap Idn, thi chiing hoat ddng nhu cac thiet bi sd vdi miic trgng thai trd khang va dugc dieu khien bang miic dien ap ludng cue [8], [9], cd dac tuyen 1-V nhu hinh 2(b) Bai bao dugc trinh bay nhu sau Phan I gidi thieu tdng quan ve bai bao Phan II se trinh bay ve dac tinh cua memristor Phan III trinh bay nguyen ly hoat dgng cua cdng logic XOR sir dyng memristor Phdn IV la thiet kd mach nhan dang ki tu su dung memristor Phan V md phong mach bang cdng cu Cadence Theo sau do, phan VI se ket luan de tdi II TINH C H A T CUA MEMRISTOR Hinh 1: Md ta mdi quan he giiia dien tich, ddng di$n, dien ap, tir thdng Memristor dugc phat hien bdi Leon Chua vao nam 1970, ddng vai trd nhu nguyen td (a) Hinh 2: (a) Memristor; (b) Dac tuyen I-V cua memristor sii dung dien ap Idn Tgp Chi Khoa Hpc Gido Dgc Ky Thudt (32/2015) Trudng Dgi Hpe Su Phgm Ky Thugt TR Hd Chi Minh Bai bao chi tap trung phan tich vao khia canh hoat dgng nhu mdt thiet bi sd cua memristor Nen dac tuyen I-V trudng hgp gidng nhu hinh 2(b) Hinh the hien mdi quan he giiia ddng dien va dien ap, thdng qua dd cho thdy tinh chat trd khang ciia memristor Trd khang se dugc giii khdng ddi didn ap dat vao (V^^^^) khdng vugt ngoai nguong [VQP^^, V^^^og^] va dao trang thai trd khang sir dung dien ap ngoai nguong \y^ V and Rp= R^^ Miic logic ' ' nghTa la: V ^ ^ 0, R , = RoPP,andR,-R^Pp III NGUYfeN LY HOAT BQ^G CUA C O N G XOR Sty DUNG M E M R I S T O R Cau tnie mach XOR sir dyng memristor, ehuydn mach CMOS va dien trd [13] Vi kha nang tich hgp cao ciia nguyen td memristor nen cau tnie mach cd m^t dp tich hgp cao hon cdng nghe CMOS truyen thdng Cau tnie mach chi tiet dugc trinh bay hinh 3(a), vdi ngo vao: ngo vao di^n ap Vj^ (x) va ngo PEN' 'CLOSE-I" Khi dd, memristor dugc xem nhu mdt thiet vao memristor R^ (y), ngo la memristor hi trd khang nhd luong cue, gdm cd trang Rp (p') Khac vdi cdng XOR truyen thdng, thai hd khang Trd khang d miic thap dugc ki qua trinh xii ly cua mach thyc thi qua budc hieu RQJ^, h d khang d miic eao dugc ki hieu la nhu hinh 3(b) Va bang su that tuong RQPP [10] Trd khang gia dinh se chuyen hang img giua ngo vao vdi ngo dugc trinh thai hi R^^^p sang R^^ (hay R^^^ sang R^^^) vdi bay nhu hinh 3(c) Ngo d budc la p, khoang thdi gian chuyen mach Tg = dat ngd budc la p ' , day la ket qua cudi cimg vao dau memristor mot mirc dien ap V^^.^ cua ngd De mach hogt dgng hieu qua, thi (hay V^.^) vdi bien dp Idn hon (hay nhd hon) gia tri cua Vp, V^ phai dugc lua chpn phu hgp mire dien ap ngudng V^^^g^ (hay V^p^^) Ddng va thda man rang budc [7] ( vdi a = K^^J thdi, qua hinh can phai thuc hien hong R „ , a n d p = R „ / R ) : mdt khoang thdi gian T^j^^p phu hgp [11], [12] Md hinh dac tinh ciia memristor dugc KjEr < X VciosE (1) md ta bang ngdn ngii Verilog-A Cac thdng sd thiet hi dugc sii dung phan sau cua bai bao nay: R^^p - kH, R„, = kH, V,^^^^ I'sn.Xl+Wxl'^i-Ca + fflxVnoK (3) 3-5 V, V,p,, - -3.5 V, - 0, T „ , , , - 10 us, R3 = k n , Vgp^ = V, Vj,g.p = -5 V Vdi qui udc: miic logic ' ' nghTa la: V^= V^^^, R ^ - R^^, Ys Vx Rp -ffi (a) ISx Rs: -u-t sT (b) Vp Step-I VRST Step-II VsET (c) X 0 1 y 1 Si S2 0 I P P fo\ 0 Mode 1 ; p'=y il : 1,0,' p'=y Hinh 3: (a) Mach cdng XOR sir dung memristor, (b) Qua hinh xu ly, (c) Bang su that ciia cdng XOR Tgp Chi Khoa Hpe Giao Due Ky Thugt (32/2015) Trudng Dgi Hoc Su Phgm Ky Thugt TR Hd ChiMinh Trudc qua trinh xii ly xay budc, ngo vao dugc gan gia tri trudc Sau dd, budc ^' ^p " '^Rsp S, - '1', S, - '0', nen Rp dugc ndi tat xudng ddt, va vdi miie dien ap V^.j d chan Vp dugc dat hoan toan len Rp, lam cho trd khang eiia memristor Rp dugc dua ve miic '0' (R(jFp), bat chap ngd vao x, y dang d trang thai nao Giai he thu dugc: i, 0.64 mA; i, = 1.18 mA; i^ = 1.82 mA Nen V^ ^ i, X Rp = 3.2 V Nen Rp se giii nguyen trang thai '0' hay p' ^ '0' Vp=VsET Vp=VsET VX=VEVL VRY Trong budc 2, Vp = V^^ S, = '0', S, - ' 1' Khi X = '0', thi S^ khdng ddn, Rp va R^, dugc mac ndi tiep va ndi xudng dat thong qua S, nhu hinh 4(a), V^^^V^X R/(R^-i-R^.muy = '0',tillV^ = 2.5 V, h-d khang Rp khdng ddi, Hmh 4: Mach hmh dugc ve lai: (a) Budc nen p' = 'C N^u y - ' 1', thi V^ - 4.16 V, trd vdi Vx = 0; (b) Budc vdi Vx = V^^ > khang Rp dao trang thai, nen p' = ' 1' rV THIET KE M^CH NHAN DANG KI TU" SU" D VNG MEMRISTOR Nguge lai, x = ' 1', hay V^ (>0), Trong nhieu ling dung nhan dang mau cua thi Sj^ din, Rp va Ry se duac mac song song va am thanh, ki tu, hinh anh, hay nhieu noi tiep vod R^ nhu hinh 4(b) phantichdii Ueu khoa hpc ciia hau, khdng Neu y = '0' thi ta co he phuong trinh (5): gian, y hpe , phep nhan giua mau du lieu ngo vao va dii lieu tham chieu dugc luu tru (il + i2-h = trudc la mdt phucmg phap nham xac dinh su (5) ddng dang ca ban de nhan dang cac mau dii I 5ii + 13 = lieu ngo vao Giai phuong trinh thu dugc: ij = 0.77 mA; i,-0.37mA;i3= 1.14 mA Vjy = i, X Rp = 3.85 V Nen Rp se chuyin trang thai tii 'O'sang '1', hay p ' ^ '1' Tuong tu, neu y = ' 1' thi ta cd he phucmg trinh (6): il + 12 - ia = Sil - iz = Sil + 13 = (6) Cdng XOR xay dung hi memristor dugc sii dung nhu la mdt phan tir nhan, dimg de thiet ke mach nhan dang ki ty Mdt hai ngo vao ciia cdng XOR dugc dimg de luu trii du lieu tham chidu (R^), ngo vao cdn lai (Vj^) dung lam ngo vao cua mach L phan hi nhan XOR dugc su dyng de xay dung mach nhan dang ki tu nhu hinh Ngd ciia mach la dien ap VjjY dat hen dien trd R^ Ngoai ra, mach cd them mdt ngd vao dieu khien ap Vp Vi vay, ndu dimg L cdng XOR, thi mach se gdm L+1 ngo vao va mdt ngo nhu hinh 5(b) Tgp Chi Khoa Hoc Gido Bgc Ky Thugt (32/2015) Trucmg Bgi Hoc SuPhgm Ky Thudt TR Hd ChiMinh 3^^^—'• (b) (a) Hinh 5: Mach nh$n d?ng ki tu sir dyng bd nhan: (a) Vdi cdng XOR thdng thudng; (b) Vdi cdng XOR su dyng memristor Hinh 5(a) la mpt dang mach nhan dang, sir dung cac phdn hi nhan XOR theo cdng nghe CMOS truyen thdng Ngd cua cac cdng XOR la di€n ap, mang muc logic '0' va '1', khdng the ket hgp trye tiep vdi nhau, vi v|iy phai su dyng them mpt bd cdng ngo Sd ngo vao cua mach cang Idn, thi cau tnie bd epng cang phiic t^p, thdi gian xii ly eang lau Trong do, hinh 5.1(b) la mach nhan dang sir dyng eae phan tii nhan XOR ed chiia mem- Xi \ "p - ristor Ngd cua cac cdng XOR la trd khang Rp^, nen cd the ket hgp vdi nhau, tdng trd cua cac ngo cua cac cdng XOR dugc tinh thdng qua didn ap Vp ma khdng can diing thdm bd cpng Vdi kien tnie mach nay, thi tdc dp xii ly hoan toan khdng phy thupe vao sd lugng ngd v^o, vi^c them, bdt ngo vao ciing khdng gay anh hudng den toan mach Cau tnie chi tidt cua mdt cdng XOR dua tren memristor dugc sir dyng m^ch nhan dang nhu hinh mW\ pyy^- Hinh 6: Cau trie cong XOR su dung memristor C4u trie c6ng XOR hinh tuong tu nhu cdng XOR hinh 3, dugc thuc thi qua budc, va co them chuy6n mjch Sj va S^, dimg da tinh dien ap ng6 cua m^ich o buoc III nhu bang Tgp Chi Khoa Hge Gido Bgc Ky Thugt (32/2015) Truimg Bgi Hge Su Phgm Ky Thudt TR Hd Chi Mmh Bang 1: Trinh tu thg:c thi ciia mach n h ^ dang Id tu S, Sa s, SB Ch^dv V 1 Reset V 1 XOR 0 Evaluate Budc Vp I 11 m V SET EVL Ngd vao R^j (y,) cua cac cdng XOR ddng vai trd luu trii dii lieu tham chieu, va dugc dat ed dinh la R^p^CO') Cac ngo vao V^^^ (x^) la cac ngo vao ciia mgch Qua trinh xir ly ciia mach n h ^ dang dien theo budc nhu bang Trong budc I va II, cac phan hi XOR thyc hien phep nhan mdt bit nhu cdng XOR hinh 3, de tinh toan trd khang ciia Rp^ Vdi ngo vao R^i deu dugc cd dinh la R^^^p, nen ngo vao Vj^j cd gia tri logic la ' ' , thi Rp^ se dao hang thai len ' T (R^j^); nguge lai, V^^^ cd gia tri logic la '0', thi Rp, giu nguyen trang thai '0' (Rppp) O budc III, cac chuyen mach S,, S^, Sj deu ngung dan, S^ dan Cac memristor Rp^ dugc each Iy vdi mach va ket ndi song song vdi nhu hinh mm -FTnm ¥ms Hinh 7: Mach hinh 5(b) dugc ve lai d budc III Theo hinh ta cd: Rp Rpo _ Kpi VpXRo _ VxY = Rp+Rp "Pi-i VEVI,XRP Rp+Ro (7) (8) buac iil, Vp va Rp phai thoa man rang bupc sau: V OPEN