n"A A B A A AAA AA AAAAAA B A B B B BAA A VREFVCCOUTPUTGROUNDRT/CTISENSEVFBCOMP'%C:\psimwork\PWM-IC\Uc3842\UC3844.sch DDQw?V.TIMEIך>{Gz?GroundR DIODESSWIVPVDC#P&COMP0ORGATE1NOTGATE4SRFF5JKFFEVSENGONCTRLJCTOPQVVCVSSIVCCS`IDCpZENERORGATE3 OP_AMP_2]pCCC4CzCC??p#D hZ313A@{!AZC7ChCS!CV}aC~C??34 Courier Newqrqr@@r@13y!cCWCC|CxC7C?? Oscillator Courier NewB@Bt"S?D DSHD~DCDٱD??Logic Courier NewA@Av:bC3Dܼ7C?DC[CCCC??10 Courier Newqrqr@@r@i_kCCCCCC??%D hVDC40@{C>C&2CC\CC??16 Courier Newqrqr@@r@k\CHCCpCC\C??4"D hSRFF1PNBCCCCCC??ppABCzCCCCC??@BC>CCCCaC?? B BC>CC>CC>C??ppABCHCCRCCMC??@BCfCCpCCkC??@BCRCC\CCWC??@BC\CCfCCaC??@OCCCCCC??D hGroundgC%DC*DC'D?? -D hD1`-kC%DC*DC'D??1D hR1R@`-|gQCG!DC1c%DCD%Df6=D?? Comparator Courier NewB@BxX;D8Dd)LDCC*CB??4C\C>CpC*CfC?? 4^D>ChDRCcDHC?4CC>CC*CC??4C@D>CED*CCD??4^DDhD DcDD?? B\DD^DD@]DD??@MRDD\D DWDD??1D hNOT2BODDRDDPDD??@ND"DD*DD@&D??D hIcomp  CcDC$hD͈CBeD??J or N Package; D8 Package Courier NewjRÑjRCAjRCv CkDn,SCoD74CBRmD??1: COMP Courier New‘BABu CpD8oJCtD70CBRrD??2: VFB Courier NewAAAxCuD֦dCyDkS=CBRwD?? 3: ISENSE Courier New9‘9BA9BwCzD[C~D8CBR|D?? 4: RT/CT Courier NewQ%‘Q%BAQ%BxCzDjSC~DCBR|D?? 5: GROUND Courier New9‘9BA9BxCuDjSCyDCBRwD?? 6: OUTPUT Courier New9‘9BA9B C^Dr޸C$cD9oCB`D??DIL-8, SOIC-8 (TOP VIEW) Courier New‘BABuCpD7CtDCBRrD??7: VCC Courier NewAAAvCkD6CoDKCBRmD??8: VREF Courier New‘BAB4C'D>C,D*C*D??4C4D>C9D*C6D??a=DB D C@D C?S'D hIVCCS2A"0I +?|B@Q D}CD?CDj= C??11m Courier Newԕ-ԕ-A@-A=A"0N>C\CDpCCfC??JD hCTOP3B@ D C D*C D%C??@OACBD CDC??D hGroundB\DBDCDB??@giCCCCCC?? -D hD2`-B"DHC^DHC@DHC??BkpCDC"DzC@D??1D hR8R@`-kpC DCDzCD??1D hR7R@`-]CCCCCC??##D hP1A"0K=U?]CCCCCC??##D hP2A"0n?`CHCCpCC\C??E&D hVSEN1A"0?8RC4CzCHCfC>C??GNDBzCBzCCzCB??@BCBCRCC%C??4B4BzCBCBCB??ppABC\CC\CC\C??ABzCCCCCC??ppABzCCCCCC??ppA`CCCCCC??E&D hVSEN3A"0?BCCCCCC?? ABCCCCCC?? ABCCCCCC??@BCCCCCC?? BBCCCCCC??@BCCCCCC?? BBCCCCCC??ppABCCCCCC?? BBzCCzCCzCC?? ABzCCzCCzCC??@BCCCCCC??@BCCCCCC??@BCCCCCC??ABzCDCDCD??ppABCDC%DCD??ABCCCCCC??AB %DC%DD%DC??B8RC DzC%DfC"D??GND9RCDzC DfC D??VREF8CCCCCC??GNDB DC DC DC?? BB DC DD D D??BBCC DCCC??B8#RCCzCDfCC??GNDB'zCCCCCC??A`( D%DD/D@D*D??E&D hVSEN4A"0?8)CED DJDDHD??GNDB.'D,D'D6D'D1D??AB0'D6D/D6D@+D6D??ppA`1 D@DDJDDED??E&D hVSEN5A"0?84 D1DD6DD4D??GNDB5 D,D D4D D@0D??ppAB8DEDDEDDED?? AB9D/DDEDD@:D??4B4B:zC>CzCfCzCRC??AB;zCfCCfCCfC??ppAB=zC4CzC>CzC9C??@8> D CD4CD*C??GNDBID*DD*DD*D??@BJD'D D'D@D'D??ppABLD4D D4D@D4D??ppABNC'DC'DC'D??ppABO;D6DCD6D@?D6D??ppABP;DDCDD@?DD??ppABR>CBzCB\CB??ABT>CfCzCfC\CfC??ABV>CCzCC\CC??ABX>C*DC*DkC*D??44BBZ>C6DC6DC6D??BB\>CCD DCDCCD??44CB] DD/DDDD??Bt^C"DC,DC'D??:D hOP_AMP1P@PB`C'DC6DC/D??ABaC,DC4DC@0D??ppAcUC|HB)D\BvTCdqB??PSIM Model for UC3844 Courier New¾Q%BQ%ABdCBIDTBT$DB??*11 mA is the IC operating supply current. Courier NewPEÝPEC@PECBeC4DC4DC4D??B`f"DRC/DzC(DfCE&D hVSEN6A"0?9gD>CDRCDHC?VREF8hDCDC DC??GNDaiD\CDCDpC??Q'D hVVCVS1A"0@zjDeCNDuCrgDԿmC??5 Courier Newqrgqrg@@rg@iA"0BlDzCDCDC??@BmDCDCDC?? ABnDCDCDC??ABo"DHC"D\C"DRC?? ABpDCDCDC?? ABqDC"DCDC??ppABr"DpC"DC"DC??ABtDHC"DHCDHC??ppABxD4CDHCD>C?? AB|DHCD\CDRC?? AB~/DfC/DC/DC??BBCHCCHCCHC??@BCpCCpCCpC??@BCfCCfCCfC??@BDfCDfC@ DfC?? BB%DC/DC*DC??AB DBDB@DB?? BBCB DBCB??CBDCDfCD>C?? BBCC%DCDC??CtCQDCUDx CSD??Note: Courier NewA@ACUD_hDlYD3DwWD??;- All functions of the IC are modelled, including the UVLO Courier NewQÝQC@QCCkDdDnD!2DlD??9- This model applies to UC1844 (Ta = -55 oC to +125 oC), Courier New"JÝ"JC@!JCCuDVODxDVODvD??Y- After modifying the UVLO threshold, the model can also be used for UC1845/2845/3845. Courier NewÝC@CDBD2D8tD D=|D??UCx844: 16V / 10V Courier NewB@B\5Dh[DMDDH_Dt#DX]D??%and pulse-by-pulse current limiting. Courier New_0Ý_0C@`0CDpDzDsDD?DqD??BUC2844 (Ta = -40 oC to +85 oC), and UC3844 (Ta = 0 oC to +70 oC). Courier New:kÝ:kC@8kC|DD2DD&DD??UVLO On/Off Courier New < - UCx842 and UCx843 can operate the duty cycle close to 100%; Courier New\Ý\C@\CDDnrDD :DD???whereas the maximum duty cycle for UCx844 and UCX845 is 50%. Courier New6`Ý6`C@6`CCDC|DoD=DwD??F- A grounded op. amp. (OP_AMP) can be used for the error amplifier Courier NewayÝayC@`yCDD|DDfz?DD??Eif the IC reference ground is connected to the power circuit ground. Courier NewuÝuC@uCK\C`DBtDtdD49DbD??B- The propagation delay is not modelled. It can be included by Courier New:kÝ:kC@9kCD~ReD{jDh2iD7DsBgD??:adding time delay blocks (TDELAY) at the gating output. Courier New!NÝ!NC@!NC .END