Introduction to Sequential Logic Circuits .

What is a Sequential Logic Circuit?

A Sequential logic circuits is a form of binary circuit; its design employs one or more inputs and one or more outputs, whose states are related to some definite rules that depends on previous states.

Dissimilar Combination Logic circuits can change state depending on the real signals that are applied to their inputs, at the same time,Sequential Logic Circuits include some form of inherent “Memory” build into them as they are capable of taking into account their previous input state as well as the individuals really present, a sort of “before” and “after” effect is involved with the sequential logic circuits.A very simple sequential circuit with no inputs can be created using inverted to form a feedback loop.

Fig:Sequential Logic Circuit Block Diagram

Design Procedure of Sequential Logic Circuits:

1.This procedure involves the following steps

2.First, derive the state diagram

3.Take as the state table or an equivalence representation, such as a state diagram.

4.The number of states may be reduced by the state reduction technique

5.Verify the number of flip-flops needed

6.Choose the type of flip-flops to be used

7.Derive excitation equations

8.Using the map or some other simplification method, derive the output function and the flip-flop input functions.

9.Draw a logic diagram or a list of Boolean functions from which a logic diagram can be obtained.

Types of Sequential Logic Circuits

There are three types of sequential circuits:

Event Driven
Clock Driven
Pulse Driven

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