Ripple adder
- 1. By T.Mounika
- 2. Introduction Arithmetic operations like addition, subtraction, multiplication, division are basic operations to be implemented in digital computers using basic gates like AND, OR, NOR, NAND etc. Among all the arithmetic operations if we can implement addition then it is easy to perform multiplication (by repeated addition), subtraction (by negating one operand) or division (repeated subtraction).
- 3. Binary addition is a fundamental operation in most digital circuits There are a variety of adders, each has certain performance. Each type of adder is selected depending on where the adder is to be used. Ripple carry adder is suitable for small bit applications
- 4. Basic adder circuit A combinational circuit that adds two bits is called a half adder A full adder is one that adds three bits Full Adder sum 3 inputs carry
- 5. Truth Table of fulladder Input A Input B Input C sum carry 0 0 0 0 0 0 0 1 1 0 0 1 0 1 0 0 1 1 0 1 1 0 0 1 0 1 0 1 0 1 1 1 0 0 1 1 1 1 1 1
- 6. Ripple carry adder The ripple carry adder is constructed by cascading full adder blocks in series The carryout of one stage is fed directly to the carry-in of the next stage For an n-bit ripple adder, it requires n full adders
- 7. Block diagram of 4 bit ripple adder
- 8. Truth table of ripple carry adder A1 A2 A3 A4 B4 B3 B2 B1 S4 S3 S2 S1 carry 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 1 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 0 1 1 0 1 0 1 0 1 0 0 1 0 0 1 1 1 0 0 1 1 0 0 1 0 0 0 1 1 1 1 0 1 1 1 0 1 1 0 0 1 1 1 1 1 1 1 1 1 1 1 1 0 1
- 11. LAYOUT
- 12. Advantages We can add two n-bit numbers easily It is advantageous for less number of bit operations