A Dual Transformation Approach to Current-Mode Filter Synthesis
Kenzo Watanabe, Guohua Wang, Yutaka Fukui · Shizuoka University Repository (Shizuoka University) · 1992
A dual transfbrmationincorporatlng the 丘equency-dependent scaling fhctorwith theimpedance dimen-Sionisproposedtosynthesizethecurrent-mOdecounterpartofa VOltage-mOdeorlglnal．Ageneralclassorcurrent-mOdeactive-RCbiquadraticfiltersandaswitched-CaPaCitorlow-paSSbiquad arederivedtodemonstratethesynthesisprocedure・Theirsimulationandtestresultsshowthatthecurrenttransftrfunctionsare thesameasthevoltagetransftrfunctionsoftheorlglnals，and thusconfirmthevalidityortheprocedure・Thedualtransfbrmationdescribedhereinisgeneralinthatwiththescalingfactor ChosenapproprlatelyltCanmeetaWidevarietyofcircuittransfbrmation，and thus useful also fbr circuit classification and identification． 点呼仰r九・血α／血刀ゆ′川の加，C〟仰如一明0(ねJ肋eれαCかe月C α〃d∫c cかC〟〟∫ 1．Introduction Current-mOde slgnal processinglS a reCent hot toplCinanalogICdesign，butitshistorygoesbackto 1968 when the first current conveyor(CCI)was presented as a powerfulbuilding block(1)・Unfbrtunately，thiswasalmostthesametimewhenmonolithic Op-ampS became commercial at a reasonable prlCe・ SincecircuitenglneerShadbeenfamiliarwithvoltagemodeslgnalprocesslng，1ittleattentionwaspaidtothis newdevice・Twentyyearslater，ithasbeenhighlighted asabreakthroughfbrhighdenslty，VLSIimplementationofanalogfunctions(2)・(3) A number ofnovelbuilding blocks are now exploredtomakeuseofsuchadvantagesofcurrent-mOde Slgnalprocessing as wide bandwidth，Wide dynamic range，lowpoweroperation，andeasylmplementation Ofanalogarithmeticfunctions・TyplCalsuchexamples are theimproved current conveyors(4)and mirrors(5)， Current amplifiers(6)，SWitched-Current SOurCeS(7)，Current coplerS(8)，and comparators(9)・While a wide Varietyofanalogfunctionscanbeimplementeduslng thesebuildingblocks，theirsynthesisprocedure，eSpe-Ciallyln thefilter synthesis，Still fbllows that estab-1ishedin voltage terms・Therefbre，the voltage-tO-Current domain conversionlendsitselfto a straight-Manuscrlpt reCeived August20，1991． ManuscrlptreVisedJanuary17，1992