Boolean algebra simplification and combination circuits
JaipalDhobale
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238 slides
Dec 13, 2017
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About This Presentation
Boolean algebra simplification and Combination circuits
Size: 1.92 MB
Language: en
Added: Dec 13, 2017
Slides: 238 pages
Slide Content
UNIT II
Boolean Algebra Simplification
and Combinational Circuits
By Dr. DhobaleJ V
Associate Professor
School of Engineering & Technology
RNB Global University, Bikaner
RNB Global University, Bikaner. 1Course Code -19004000
Boolean Algebra –Simplification
StandardformofBooleanexpression:
TheSum-of-Products(SOP)Form.
Whentwoormoreproducttermsaresummed
byBooleanaddition,theresultingexpression
isasum-of-products(SOP).
Ex. AB + ABC
ABC + CDE + BCD
AB + BCD + AC
Also, an SOP expression can contain a single-
variable term, as in A + ABC + BCD.
12RNB Global University, Bikaner.Course Code -19004000
Boolean Algebra –Simplification
StandardformofBooleanexpression
TheProduct-of-Sums(POS)Form:Asum
termwasdefinedbeforeasatermconsisting
ofthesum(Booleanaddition)ofliterals
(variablesortheircomplements).Whentwoor
moresumtermsaremultiplied,theresulting
expressionisaproduct-of-sums(POS).
Examples -(A + B)(A + B + C)
(A + B + C)( C + D + E)(B + C + D)
(A + B)(A + B + C)(A + C)
21RNB Global University, Bikaner.Course Code -19004000
Boolean Algebra –Simplification
StandardformofBooleanexpression
TheProduct-of-Sums (POS)Form:
ConvertingaSumTermtoStandardPOS-
(A + B + C)(B + C + D)(A + B + C + D) = (A +
B + C + D)(A + B + C +D) (A + B + C + D)(A +
B + C + D) (A + B + C + D)
31RNB Global University, Bikaner.Course Code -19004000
Boolean Algebra –Simplification
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Boolean Algebra –Simplification
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Boolean Algebra –Simplification
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KARNAUGH MAP MINIMIZATION
KARNAUGH MAPSOPMINIMIZATION:For
anSOPexpressioninstandardform,a1is
placedontheKarnaughmapforeachproduct
termintheexpression.
Each 1 is placed in a cell corresponding to the
value of a product term.
57RNB Global University, Bikaner.Course Code -19004000
KARNAUGH MAP MINIMIZATION
KARNAUGH MAPSOPMINIMIZATION:
Solution–b. For a 4-variable map:
1.A 1-cell group yields a 4-variable product term
2.A 2-cell group yields a 3-variable product term
3.A 4-cell group yields a 2-variable product term
4.An 8-cell group yields a 1-variable term
5.A 16-cell group yields a value of 1 for the
expression
72RNB Global University, Bikaner.Course Code -19004000
KARNAUGH MAP MINIMIZATION
KARNAUGH MAPSOPMINIMIZATION:
Solution–Theresultingminimumproductterm
foreachgroupisshowninfigaboveThe
minimumSOPexpressionsforeachofthe
Karnaughmapsinthefigureare:
(a)AB+BC+ABC (C) AB + AC + ABD
(b) B + A C + AC (d) D + ABC + BC
74RNB Global University, Bikaner.Course Code -19004000
KARNAUGH MAP MINIMIZATION
75RNB Global University, Bikaner.Course Code -19004000
KARNAUGH MAP MINIMIZATION
76RNB Global University, Bikaner.Course Code -19004000
KARNAUGH MAP MINIMIZATION
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KARNAUGH MAP MINIMIZATION
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KARNAUGH MAP MINIMIZATION
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KARNAUGH MAP MINIMIZATION
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KARNAUGH MAP MINIMIZATION
81RNB Global University, Bikaner.Course Code -19004000
KARNAUGH MAP MINIMIZATION
82RNB Global University, Bikaner.Course Code -19004000
KARNAUGH MAP MINIMIZATION
Simplify–usingKarnaughMap
ABC+ABC+ABC+ABC
A BC0001 1110
0
1
95RNB Global University, Bikaner.Course Code -19004000
1
1 1 1
KARNAUGH MAP MINIMIZATION
Simplify–usingKarnaughMap
ABC+ABC+ABC+ABC
A BC0001 1110
0
1
96RNB Global University, Bikaner.Course Code -19004000
1
1 1 1
KARNAUGH MAP MINIMIZATION
Simplify–usingKarnaughMap
ABC+ABC+ABC+ABC BC
A BC0001 1110
0
1 AB
AC =AC+BC+AB
97RNB Global University, Bikaner.Course Code -19004000
1
1 1 1
Multiplexer & De-multiplexer
Multiplexer:Applications:Multiplexerareused
invariousfieldswheremultipledataneedto
betransmittedusingasingleline.Following
aresomeoftheapplicationsofmultiplexers
1.Communication system –Multiple data
2.Telephone network –Multiple Audio signals
3.Computer memory –Bus to storage
4.Transmission from the computer system of a
satellite -GPS
142RNB Global University, Bikaner.Course Code -19004000
Decoder -Encoder
CodeConversion:Gray-to–binary
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Decoder -Encoder
CodeConversion:Gray-to–binary
187RNB Global University, Bikaner.Course Code -19004000
Decoder -Encoder
CodeConversion:Gray-to–binary
188RNB Global University, Bikaner.Course Code -19004000
ROM & Programmable Logic
Thenextthreecombinationalcomponentswe
willstudyare:ROM,PLA,andPAL.
ROM'sPLA'sandPAL'sarestorage
Components.
Amoreprecisedefinitionis:acombinational
componentisacircuitthatdoesn'thave
memoryofpastinputs.(Theoutputsofa
combinationalcomponentarecompletely
determinedbythecurrentinputs.)
189RNB Global University, Bikaner.Course Code -19004000
ROM & Programmable Logic
ROM:AROMisacombinationalcomponent
forstoringdata.Thedatamightbeatruth
tableorthedatamightbethecontrolwordsfor
amicroprogrammedCPU.(Controlwordsina
microprogrammedCPUinterpretthemacro
instructionsunderstoodbytheCPU.)
AROMcanbeprogrammedatthefactoryor
inthefield.
Thefollowingimageshowsthegenericformof
aROM:
190RNB Global University, Bikaner.Course Code -19004000
ROM & Programmable Logic
ROM:(x=log
2n<=>2
x
=n)
191RNB Global University, Bikaner.Course Code -19004000
ROM & Programmable Logic
ROM: An n x m ROM can store the truth table
for m functions defined on log
2n variables:
192RNB Global University, Bikaner.Course Code -19004000
ROM & Programmable Logic
ROM:Example:Implementthefollowing
functionsinaROM:
F
0=A
F
1=A'B'+AB
SinceaROMstoresthecompletetruthtable
ofafunction(oryoucouldsaythataROM
decodeseverymintermofafunction)
Thefirststepistoexpresseachfunctionasa
truthtable.
193RNB Global University, Bikaner.Course Code -19004000
ROM & Programmable Logic
ROM:
For the discussion that follows it may be
helpful to keep in mind the canonical form of
the function also:
F
0= AB' + AB
F
1= A'B' + AB
194RNB Global University, Bikaner.Course Code -19004000
ROM & Programmable Logic
ROM:
WeuseaspecialnotationtoshowtheROM
implementationofafunction:
195RNB Global University, Bikaner.Course Code -19004000
ROM & Programmable Logic
ROM:
Theimageaboveshowshowa4x3ROMcan
beusedtoimplementthetwofunctionsF
0and
F
1.(Note,thereisroomintheROMfor3
functionsoftwovariables.F
2isn'tused.
196RNB Global University, Bikaner.Course Code -19004000
ROM & Programmable Logic
ROM:
ROMsprogrammedatthefactoryarecalled
maskROMSbecauseduringfabricationthe
circuitpatternsaredeterminedbyamask.
Thereareseveraldifferenttypesoffield
programmableROMS:
PROM(ProgrammableRead-OnlyMemory)-This
isthetypethatwasdiscussedabove.Connections
arefusedandburnedinthefieldwithaPROM
programmer.
197RNB Global University, Bikaner.Course Code -19004000