Browse Prior Art Database

RIPPLE BINARY MAGNITUDE COMPARATOR CELL

IP.com Disclosure Number: IPCOM000005566D
Original Publication Date: 1985-Oct-01
Included in the Prior Art Database: 2001-Oct-16
Document File: 3 page(s) / 82K

Publishing Venue

Motorola

Related People

Donnie Anderson: AUTHOR

Abstract

A single-stage binary magnitude comparator is described which may be used to compare unsigned binary quantities of any or unequal length.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 65% of the total text.

Page 1 of 3

0 M MmROLA

Technical Developments Volume 5 October 1985

RIPPLE BINARY MAGNITUDE COMPARATOR CELL by Donnie Anderson

ABSTRACT

A single-stage binary magnitude comparator is described which may be used to compare unsigned binary quantities of any or unequal length.

DESCRIPTION

This Call compares the corresponding order of magnitude stages of two unsigned binary quantities, A and
B. Comparison propagates from the most to the least significant stages. There is no limit to the lengths of A and
B. The comparison outputs will settle to the correct result once A and B have stabilized. The cell features low tran- sistor count (24 in CMOS) and may be readily stepped or cascaded in an integrated circuit.

Inputs:

Ai and Bi: Gi and Li:

outputs:

i-th stages of the two quantities being compared. "Greater Than" and "Less Than" outputs from the next more significant stage. In the most signifi- cant stage, these inputs are tied to Logic 0.

Gi-1 and Li-1: "Greater Than" and "Lass Than" inputs to the next less significant stage In the least significant stage, the Gi-1 and Li-1 outputs are the results of the compare as follows: If: Quantity A > Quantity B, than Gi-1 = Logic 1, Li-1 = Logic 0.

Quantity A < Quantity B, than Gi-1 = Logic 0, Li-1 = Logic 1. Quantity A = Quantity B, then Gi-1 = Li-1 = Logic 0.

Note: Gi-1 = Li-1 = Logic 1 is not a staba output state. Figure 1 is the desired truth table. Minimizing the Truth Table yields:

G,, = Giti + AiLi& L,., = G,L, + A,B,G, Applying DeMor...