CMOS图像传感器中分段电容DAC非理想因素研究.pdf

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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图像传感器中分段电容DAC非理想因素研究术孙权，姚素英，徐文静，聂凯明，徐江涛(天津大学电子信息T程学院，天津300072)摘要：CMOS冈像传感器信号处理中通常采用分段电容DAC产生斜坡参考电压．研究了分段电容DAC精确的电容欠配及寄生与其转换精度的关系式。基于对分段电容DAC工作原理的研究，导m了电容失配及寄生模型；

5、针对其分数桥接电容失配、各二进制电容问的失配及寄生电容问题进行了理论分析；对分段电容DAC进行非理想因素仿真，设计了一个采用分段电容DAC的10化单斜ADC并对其进行测试，仿真和测试结果均验证了理论分析的正确性。上述理论分析结果可作为分段电容DAC的设计指导．．关键词：微电子学与体电子学；分段电容DAC；电容失配；寄生；转换精度中图分类号：TN402文献标识码：A文章编号：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[