Active C Simulated RLC resonator

Transcription

1 0 nternatonal onference on rcut, Sytem and Smulaton PST vol.7 (0) (0) AST Pre, Snapore Actve Smulated L reonator Abdul Qadr Department of Electronc Enneern NED Unverty of Enneern and Technoloy Karach, Paktan aqadr@yahoo.com q_qadr@neduet.edu.pk Abtract: n th paper a novel actve- crcut propoed whch realze all the three bac flter functon n current mode. t ue only two OTA. t electroncally tunable, the tunn rane ben lnear over four decade. Snce rounded capactor are ued, t utable for mplementaton n MOS technoloy. Th crcut bacally a reonator and an actve equvalent of pave L network. Key word: Actve-, urrent mode, electronc tenablty, MOS technoloy, reonator, current mrror.. ntroducton Actve reonator crcut have been n ue n the pat n flter crcut, whch were operatonal amplfer (OA) baed [,,5]. n uch crcut control could be obtaned ether un external pave component uch a retor/capactor or un nternal dynamc of OA whch wa carred out by chann the upply voltae of the crcut. Th not alway convenent to do o. Further uch tunn arranement are not utable for crcut when t to be mplemented n form. Moreover, n uch approache the lmtaton of rane another problem. Propoed crcut ue OTA whch have electronc tubablty [6,7]. n [3], an L reonator un OTA wa reported but t wa n voltae mode. Another L reonator wa reported n [4] whch ued three OTA. More over t ued prorammable nterator whch employed addtonal capactor and buffer whch add to the hardware. The propoed crcut n current mode, whch ha ome addtonal advantae. The mathematcal operaton (uch a addton, multplcaton etc) become eay a compared to voltae mode. Moreover, other advantae nclude low voltae requrement, low power conumpton, utablty of mplementaton n mcro- mnaturzaton [8,9,0,]. Moreover, the propoed crcut actve type, whch make t utable for mplementaton n MOS technoloy.. rcut Decrpton.. L wth pave element A parallel L crcut hown n F.(a) and t behave a flter vn all three bac repone n current mode. The routne analy of crcut of F.(a) yeld the current mode tranfer functon, whch how that the current mode repone at retance band pa, acro nductance t low pa and acro capactance t hh-pa. 34

2 c L L F.(a): L reonator wth pave element (). L L..(). L...(). L Eqn.(), () and () realze band pa, low pa and hh pa repone repectvely. 70mA 60mA 40mA LP HP BP 0mA 59KHz 0KHz 30KHz 00KHz 300KHz.0MHz (L) -() -() F.(b): The repone of crcut n F.(a) The pole frequency of th current mode flter of F.(a) : f o.. (v) π L The value of L00μH, 0nF and 00 Ω were ued n mulaton. Wth thee value the pole frequency work out to be 59.3 KHz. Th can be een n the mulaton reult of F.(b)... Propoed Actve- Smulated eonator Th tructure mulated un actve component OTA (nle output ). The propoed crcut hown n F.. The traht forward analy n current mode ve nput mpedance: 35

3 A B - o o - b 3 b F.: Propoed Actve- reonator ( ) m m m.. (v) V The equvalent -doman form : Y G...(v) L omparn (v) and (v) we have: G m ;... L... and.....(v) m m Th how that the crcut behave a parallel L network n whch conductance and nductance are crcut parameter n mulated form. t can be een that conductance and nductance are electroncally tunable. Aan the analy of the crcut of F. yeld the follown current mode tranfer functon: ( ). (v) ( ) m m m. Th realze hh pa operaton. m 3( ). (x) m m m. Th realze band pa repone. Thee repone are hown n F.4(a). The current nput at node A. Snce t current mode approach, the node A and node B may be treated dfferent and current dvon may be appled at A (th cannot be done n voltae mode a pont A and B wll be at the ame potental). The current can be obtaned from here un a current mrror. At A t dvde nto two branche.e. nto and toward node B. Lookn nto the network from pont B (.e. ahead of capactor ), by routne analy t nput mpedance ven by:. (x) V Th mean that lookn nto node B, t mulate an nductor alonwth an conductance. Further the current mode tranfer functon at the node B yeld, 36

4 . (x) Th a mxed low pa and band pa repone a could be could be antcpated n the lht of Eqn.(x). By approprate den value, the low pa repone can be made domnant. For the value choen, the crcut ve low pa repone a hown n F.4(b). The mulaton reult confrm th and the domnant low pa repone obtaned..3. Flter Parameter The pole frequency (ω o ) and pole qualty factor Q of the crcut are: ω o Q 3. Smulaton eult m (x) m. (x) To confrm theoretcal analy, the propoed crcut wa mulated un Ppce wth the follown value of the component: m m ms; 0 nf. An nput current of 0 ma wa ued. The mulaton reult are hown n F.4(a) and (b). The theoretcal reult are n ood areement wth the mulaton reult. Theoretcal frequency 3.8 KHz and the frequency obtaned from mulaton 3.8KHz. 5mA 0mA 5mA BP HP 3.KHz.0KHz 0KHz 00KHz.0MHz 0MHz -() -() F.4(a): Band pa and Hhpa repone of the propoed reonator 37

5 0mA 0mA LP.0KHz 0KHz 00KHz.0MHz 0MHz (3) 4. Acknowledement F.4(b): Low pa repone of the propoed reonator The author hereby very much ndebted to the Hher Educaton ommon of Paktan for provdn fundn for travel rant etc. for oral preentaton n the conference. 5. eference [].A.Khan and M.T.Ahmed, An Actve- reonator and t applcaton n realzn monolthc flter and ocllator, Mcroelectronc Journal, vol.4, No., pp 6-66,983. [] M.Hahmura, urrent mode hh pa, hhpa and low pa flter un Operatonal amplfer pole, nt. Jr Electr. Vol. 4, pp [3] T.Altaf and A.Qadr, ealzaton of L reonator and applcaton un OTA and rounded capactor, t EP nternatonal onre, Aprl -6, 999, Lahore [4] T.Altaf and A.Qadr, nterable Flter and ocllator un mulated pave crcut, Proc.of EEE conf. on e- Technoloe, von and challene, 5 th Nov. 000, Hotel Avar Tower Karach. [5] M.E.V.Valkenber, Analoue flter den,holt Saunder, Japan 98. [6] H.S.Malver, Electroncally tunable actve flter wth operatonal tranconductance amplfer, EEE tran. On rcut and Sytem, vol AS-9, No.5, pp ,98. [7] T.Altaf, ealzaton of multfuncton tunable monolthc flter wth operatonal tranconductance amplfer,modeln, meaurement and control, Vol. 67, No., pp -5, AMSE Pre, France, 997. [8] T.Altaf and B.Snh, Mcroproceor controlled OTA- lowpa and bandpa flter, nt.jr of electr., vol. 7, No.4, pp , 99 [9] Je Wu. urrent mode OTA- flter, nt. Jr of Electr., vol.76 (June),PP 5-0, 994. [0] J.Wu and E. El Mary, Unveral voltae and currentmodeota Baed Bquad, nt. Jr of Electr., vol.85, No.5, PP , Nov [].han, New Multfuncton OTA- Bquad, EEE Tran. rcut and Sytem-, Vol.46, No.6, pp 80-84, June