【Logic Design】 2-bit comparator

2-bit comparator

 

추천글 : 【논리설계】 논리설계 목차

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▶ Implementation in a diagram

출처: 서울대학교 논리설계(유승주) 강의

Figure. 1. Implementation in a diagram^]

 

▶ Truth table (+ encoding)

 

▶ Logic design

# LT (less than) = A'·C + (A XNOR C)·D·B'
    # cost = NOT(2) × 2 + 2-input AND(6) + 3-input AND(8) + 2-input OR(6) + XOR(8) = 32 (transistors)
    # improved cost = NOT(2) × 2 + 2-input NAND(4) × 2 + 3-bit NAND(6) + XOR(8) = 26 (transistors) (ref)

 

^]

 

# EQ (equal to) = (A XNOR C) · (B XNOR D)
    # cost = XNOR(8) × 2 + 2-input AND(6) = 22 (transistors)

 

# GT (greater than) = A · C' + (A XNOR C) · B · D'
    # cost = 32 (transistors), improved cost = 26 (transistors), Refer #LT

 

▶ Circuit design

 

입력: 2016.09.17 12:40