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1、第27卷第1期Vo1.27No.12014年1月Jan.2014ResearchonNon-IdealFactorsofSegmented—CapacitorDACinCMOSImageSensorSUNQM,YAOSwing,XUWenjing,NIEKaiming,XUJiangtao(SchoolofElectronicInformationEngineering,TianjinUniversity,Tianjin300072,China)Abstract:segmented—capacitordigitalanalogconverter(SCDAC)isusuallyu
2、sedinCMOSimagesensortogeneratearampreferencevoltage.Preciserelationshipsbetweenconversionresolutionandnon—idealfactorssegmented—capacitordigitalanalogconverterarederived.Thesenon·idealfactorsconsistofcouplingcapacitormismatchbinary·weighted—,capacitormismatchandparasiticeffects.Initially,bas
3、edonthestudyofSCDACoperationprinciple,mathematicalmodelsareestablished.Thentheeffectsofnon—idealfactorsonSCDACareanalyzed.Simulationandmeasurementresultsverifythetheoreticalanalysis.ThesepreciserelationshipsserveasaguidelineforthedesignofSCDAC.Keywords:microelectronicsandsolidelectronics;seg
4、mented—capacitorDAC;capacitormismatch;parasitic;conversi【1nresn111tionEEACC:1265H;2570Ddoi:10.3969/j.issn.1004-1699.2014.01.007CMOS圖像傳感器中分段電容DAC非理想因素研究術(shù)孫權(quán),姚素英,徐文靜,聶凱明,徐江濤(天津大學(xué)電子信息T程學(xué)院,天津300072)摘要:CMOS岡像傳感器信號處理中通常采用分段電容DAC產(chǎn)生斜坡參考電壓.研究了分段電容DAC精確的電容欠配及寄生與其轉(zhuǎn)換精度的關(guān)系式?;趯Ψ侄坞娙軩AC工作原理的研究,導(dǎo)m了電容失配及寄生模型;
5、針對其分?jǐn)?shù)橋接電容失配、各二進(jìn)制電容問的失配及寄生電容問題進(jìn)行了理論分析;對分段電容DAC進(jìn)行非理想因素仿真,設(shè)計了一個采用分段電容DAC的10化單斜ADC并對其進(jìn)行測試,仿真和測試結(jié)果均驗證了理論分析的正確性。上述理論分析結(jié)果可作為分段電容DAC的設(shè)計指導(dǎo)..關(guān)鍵詞:微電子學(xué)與體電子學(xué);分段電容DAC;電容失配;寄生;轉(zhuǎn)換精度中圖分類號:TN402文獻(xiàn)標(biāo)識碼:A文章編號:1004—1699(2014)01—0032—08NowadaysCMOSimagesensorsarebecomingsegmented—capacitorDAC(SCDAC)withacouplingco
6、mpetitivewithregardtochargecoupledevicescapacitorconnectingtwobinaryweightedcapacitor(CCD),andtheyhavebeenappliedinmanyareas,sucharraysisproposed.whichjustneeds2unitasdigitalphotography,industrialvision,medicalandcapacitors.ComparedwithtraditionalCRDAC,thespaceapplications一.SingleSlopeADCisw
7、idelynumberofcapacitorsinSCDACdecreasesappliedinCMOSimagesensorservingastheon—chipexponentially,whichresultsinhigherspeed,lowerpowercolumn—parallelADCduetoitslowpowercostandlowconsumptionandsmallerchiparea.Asaconsequence,SCDACiswidelvusedatDresent[