10
FunctionalDescription
SupplyVoltageV,V,V
LCDDDSS
ThevoltagebetweenVandVisthesupplyvoltageforthe
logicandtheinterface.ThevoltagebetweenVandVisthe
supplyvoltagefortheLCDandisusedforthegenerationofthe
internalLCDbiaslevels.TheinternalLCDbiaslevelshavea
maximumimpedanceof25kforaVvoltagefrom3to8V.
WithoutexternalconnectionstotheV1,V2,andV3biaslevel
inputs,theV6118candrivemostmediumsizedLCD(pixelarea
upto4'000mm).
Fordisplayswithawidevariationinpixelsizestheconfiguration
showninFig.13cangiveenhancedcontrastbygivingfaster
pixelswitchingtimes.Onchangingtherowpolarity(seeFig.7,
8and9)theparallelcapacitorslowertheimpedanceofthebias
levelgenerationtothepeakcurrent,givingfasterpixelcharge
timesandthusahigherRMS"on"value.AhigherRMS"on"
valuecangivebettercontrast.IfforagivenLCDsizeand
operatingvoltage,the"off"pixelsappear"on",orthereispoor
contrast,thenanexternalbiaslevelgenerationcircuitcanbe
usedwiththeV6118.Anexternalbiaslevelgenerationcircuit
canlowerthebiaslevelimpedanceandhenceimprovetheLCD
contrast(seeFig.12).TheoptimumvaluesofR,Rx,andC,vary
accordingtotheLCDsizeusedandV.Theyarebest
determinedthroughactualexperimentationwiththeLCD.
ForLCDwitheverylargeaveragepixelsizeupto10'000mm,
thebiaslevelconfigurationshowninFig.14shouldbeused.
WhenV6118sarecascadedconnecttheV1,V2,andV3bias
inputsareshowninFig.10.Thepixelloadisaveragedacrossall
thecascadeddrivers.Thiswillgiveenhanceddisplaycontrast
astheeffectivebiaslevelsourceimpedanceistheparallel
combinationofthetotalnumberofdrivers.Forexample,iftwo
V6118arecascadedasshowninFig.10,thenthemaximum
biaslevelimpedancebecomes12.5KforaVvoltagefrom
3to8V.Table8showstherelationshipbetweenV1,V2,andV3
formultiplexrates2,4and8.NotethatV>V1>V2>V3for
theV61182andV61188,andfortheV61184,
V>V1>V2.
Thedatainputpin,DI,isusedtoloadserialdataintotheV6118.
Theserialdatawordlengthis40bitswhenisinactive,and
48bitswhenitisactive.Dataisloadedininversenumerical
order,thedataforbit40(bit48whenisactive)isloaded
firstwiththedataforbit1last.Thecolumndatabitsareloaded
firstandthentheaddressbits(seeFig.4and5).
Thedataoutputpin,DO,isusedincascadedapplications(see
Fig.10).DOtransfersthedatatothenextcascadedchip.The
dataatDOisequaltothedataatDIdelayedby40clockperiods,
whenisinactiveand48clockperiodswhenisactive.
InordertocascadeV6118s,DOofonechipmustbeconnected
toDIofthefollowingchip(seeFig.10).Incascaded
applicationsthedataofthelastV6118(theonethatdoesnot
haveDOconnected)mustbeloadedfirstandthedataforthe
firstV6118(itsDIisconnectedtotheprocessor)loadedlast
(seeFig.10).
DDSS
LCDSS
Ω
Ω
LCD
LCD
LCD
LCD
LCD
2
2
DataInput/Output
COL
COL
COLCOL
ThedisplayRAMwordlengthis40bits(seeFig.6).EachLCD
rowhasacorrespondingdisplayRAMaddresswhichprovides
thecolumndata(onoroff)whentherowisselected(on).When
downloadingdatatotheV6118anydisplayRAMaddresscan
bechosen,thereisnodisplayRAMaddressingsequence(see
Fig.4and5).
ThesamedatacanbewrittentomorethanonedisplayRAM
address.Ifmorethanoneaddressbitisset,thenmorethanone
displayRAMaddressiswriteenabled,andsothesamedatais
writtentomorethanoneaddress.Thisfeaturecanbeusefulto
flashtheLCDonandoffundersoftwarecontrol.Iftheaddress
bitsareallzerothennodisplayRAMiswriteenabledandno
dataiswrittentothedisplayRAMonthefallingedgeofSTR.
Useaddress0tosynchronizecascadedV6118swithout
updatingthedisplayRAM.
LCD,andsynchronizecascadedV6118s.TheSTRinputwrites
thedataloadedintotheshiftregister,ontheDIinput,tothe
displayRAMonthefallingedgeoftheSTRsignal.Thedisplay
RAMaddressisgivenbytheaddressbits(seeFig.4and5).
TheSTRinputwhenhighblankstheLCDbydisconnectingthe
internalvoltagebiasgenerationfromtheVpotential.
SegmentoutputsS1toS40(rows andcolumns)arepulledup
toV.ThedelaytodrivingtheLCDwithVonS1toS40,is
dependentonthecapacitiveloadoftheLCDandistypically1
µs.AnLCDpixelrespondstoRMSvoltageandtakes
approximately100mstoturnonoroff.Thedelayfromputting
STRhightotheLCDbeingblankisdependentontheLCDoff
timeandistypically100ms.Inapplications,whichhavealong
STRpulsewidth(10µs),theLCDisdrivenbyVonboththe
rowsandcolumnsduringthistime.Asthetimeisshort(1µA),it
willhavezeromeasurableeffectontheRMS"on"value(over
100ms)ofanLCDpixelandalsozeromeasurableeffectonthe
pixelDCcomponent.SuchSTRpulseswillnotbevisibletothe
humaneyeonanLCD.
WhenSTRishightheLCDwillbe
drivenbytheparallelcombinationoftheexternalvoltagebias
generationcircuitandpartoftheinternalvoltagebias
generationcircuit.
TheSTRinput,whenhigh,synchronizescascadedV6118sby
forcinganewtimeframetobeginatthenextfallingedgeofthe
FRinputsignal(seeFig.6).Atimeframebeginswithrow1
andsotheLCDpictureisrebuiltfromrow1eachtime
CLKInput
STRInput
TheCLKisusedtoclocktheDIserialdataintotheshiftregister
andtoclocktheDOserialdataout.Loadingandshiftingofdata
occursatthefallingedgeofthisclock,outputtingofthedataat
therisingedge(seeFig.3).Whencascadingdevices,allCLK
linesshouldbetiedtogether(seeFig.10).
TheSTRinputisusedtowritetothedisplayRAM,blankthe
SS
LCDLCD
LCD
Noteifanexternalvoltagebiasgenerationcircuitisusedas
showninFig.12and14,theLCDblankfunction(STRhigh)
willnotblanktheLCD.
V61182/4/8