31-07-2012, 11:57 AM
Parallel Adders
Adders[.pdf (Size: 3.69 MB / Downloads: 270)
Introduction
Binary addition is a fundamental operationin 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.
Basic Adder Unit
A combinational circuit that adds two bits is called a half adder
A full adder is one that adds three bits, the third produced from a previous addition operation
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 parallel adder, it requires n full adders