Digital circuit

Digital circuits are systems that operate on digital signals (binary true/false values) with logic gates. Logic functions (or logic expressions) are closed-form, compact representations of the system using Boolean algebra.

All circuits and functions can be implemented with basic logic gates, or alternatively with NOR and NAND.

Physical implementation

Logic circuits can be implemented on three different types of chips.

• Standard chips perform a fixed function with a small amount of circuitry.
• Programmable logic devices are re-configurable by the user and can implement user-defined circuits.
  • Field-programmable gate arrays are the most common types of PLDs.
• Application-specific integrated circuits are custom-designed for a certain task, with the benefit of performance optimisation but with a major time (design, fabrication, manufacturing) downside.

Types of circuits

• Combinational circuit
  • Multiplexer
  • Arithmetic logic unit
  • Decoder
  • Encoder
• Sequential circuit
  • Flip-flop
  • Register
• Finite state machine
  • Datapath
  • Control path

Resources

• Fundamentals of Digital Logic with Verilog Design, by Stephen Brown and Zvonko Vranesic
• Logic and Computer Design Fundamentals, by M. Morris Mano and Charles Kime

See also

• Electrical circuit, which operate on continuous signals
• ECE241 — Digital Systems