Digital Design

Table of Contents


What is Digital Circuit Design?

A digital circuit is designed by using a number of logic gates on a single integrated circuit (IC). They operate with discrete logic (0's and 1's). The output obtained by processing raw digital data is a precise value. These circuits can be represented in a combinational way or a sequential way. The basic components of digital circuits are flip flops, diodes, transistors, gates, etc. [1].


How to Design a Digital Circuit

Digital circuits are normally designed through the use of a simulator. One such simulator is Circuit Verse. They offer many tools to help design your circuits. Another simulator is Circuit Lab. There are a large number of online simulators available to help design a digital circuit.


Figure 1: Circuit Verse Website

An image of the Circuit Verse website.

Figure 2: Circuit Lab Website

An image of the Circuit Lab website.


Design Steps and Tips

Here is a list of some common design tips [3]:

  • Use a block diagram. This provides an outline for your work and helps others understand your circuit.
  • Divide and conquer. Take your time designing each of the functional blocks.
  • Name your nets. Try to state their purpose since it will help with debugging and creating simulations.
  • Always take notes. Document every step of your processing when designing the circuit.
  • Be consistent in your placement of text on the diagram.
  • Make your connectors visible and easily distinguishable.


Design Issues

Since digital circuits are built up with analog components like resistors, relays, transistors, and diodes it is important to note these components do not affect the behaviour of the signal or data during digital circuit operation. Some common design issues are glitches and metastability due to improper synchronization of different clock signals [2]. The large current demand when switching states can also interfere with analog components.


Advantages and Disadvantages

Some advantages and disadvantages of digital circuits are [1]:

AdvantagesDisadvantages
  • High accuracy and programmability
  • Easy to save digital data
  • Immune to noise
  • Many DC circuits can be integrated on a single IC
  • Very flexible
  • High reliability
  • High transmission rates
  • Highly secure
  • Operate only on digital signals
  • Consume more energy than analog circuits
  • Higher heat dissipation
  • Higher cost
  • Big current demand when switching states, which can interfere with analog components


Applications

Digital circuits are used to perform operations based on the input given to the electronic circuit. Their applications range from digital watches to traffic lights. Almost every gadget used is an application of digital circuits. As digital circuits operate on an input that returns a binary value, they are also highly programmable and can be used for all kinds of binary computation and digital logic [1].


References

[1] "What is Digital Circuit : Design and Its Applications," El PRO CUS, [Online]. Available: https://www.elprocus.com/what-is-digital-circuit-design-and-its-applications/#:~:text=Definition%3A%20A%20digital%20circuit%20is,is%20of%20a%20precise%20value.

[2] "Logic / Digital Circuit Design Guidelines," Electronics Notes, [Online]. Available: https://www.electronics-notes.com/articles/digital-embedded-processing/logic-circuits-design/design-guidelines-overview.php.

[3] "8 Circuit Design Tips," EE Web, [Online]. Available: https://www.eeweb.com/8-circuit-design-tips/.

Contributors:

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Mayurakhi Khan 950 days ago
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Faculty Advisors: Allyson Giannikouris, Kim Pope, John Thistle