{"id":384,"date":"2019-08-05T22:46:37","date_gmt":"2019-08-05T17:01:37","guid":{"rendered":"https:\/\/bcisnotes.com\/secondsemester\/?p=384"},"modified":"2021-04-04T13:40:13","modified_gmt":"2021-04-04T07:55:13","slug":"combinational-circuit","status":"publish","type":"post","link":"https:\/\/bcisnotes.com\/secondsemester\/digital-systems\/combinational-circuit\/","title":{"rendered":"Combinational Circuit || Combinational Logic || Bcis Notes"},"content":{"rendered":"

Combinational Circuit<\/h2>\n

Combinational Circuit consists of logic gates whose output at any instant of time are determined by the present combination of input. Basic building blocks of a combination of the logic circuit.<\/p>\n

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Fig: Combinational Circuit<\/strong><\/em><\/p>\n

There is ‘n’ numbers of inputs line and “m”\u00a0 numbers of the output lines. for “n” inputs. There is 2n<\/sup>\u00a0 possible combination of binary values for each possible input combination.
\nIt can be discovered by M Boolean function of each output variable.<\/p>\n

Design procedure<\/strong><\/p>\n

The designed circuit starts from the verbal combination and verbal outline and ends with a logic circuit diagram.
\nThe procedure includes in the following steps:-<\/p>\n

1. Specification<\/strong>
\nWrite a specification for the circuit if one is not already available
\n2. Formulation<\/strong>
\nDerive a truth table or initial Boolean equations that define the required relationships between the inputs and outputs, if not in the specification.
\nApply hierarchical design if appropriate
\n3. Optimization<\/strong>
\nApply 2-level and multiple-level optimization
\nDraw a logic diagram for the resulting circuit using ANDs, ORs, and inverters
\n4. Technology Mapping<\/strong>
\nMap the logic diagram to the implementation technology selected
\n5. Verification<\/strong>
\nVerify the correctness of the final design manually or using simulation<\/p>\n

In simple words, we can list out the design procedure of combinational circuits as:<\/h4>\n
    \n
  1. State the given problem completely and exactly.<\/li>\n
  2. Interpret the problem and determine the available input variable and require the output variable.<\/li>\n
  3. Assign a latter symbol to each input and output variable.<\/li>\n
  4. Design the truth table which defines the required relation between outputs and inputs.<\/li>\n
  5. Obtain the simplified Boolean expression for each output.<\/li>\n
  6. Draw the Logic diagram to implement the Boolean expression.<\/li>\n<\/ol>\n

     <\/p>\n

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