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Four Device Exclusive OR CMOS Circuit

IP.com Disclosure Number: IPCOM000050334D
Original Publication Date: 1982-Oct-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 3 page(s) / 24K

Publishing Venue

IBM

Related People

Dearden, ZT: AUTHOR [+2]

Abstract

A four-device exclusive OR CMOS circuit is disclosed which operates on zero DC power, while minimizing device count, without compromising its performance.

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Four Device Exclusive OR CMOS Circuit

A four-device exclusive OR CMOS circuit is disclosed which operates on zero DC power, while minimizing device count, without compromising its performance.

The figure shows the circuit, which includes a CMOS inverter portion comprising the P channel FET 1 and the N channel FET 2. The source of the P channel FET 1 is connected to the +V power supply, and the drain thereof serves as an output node to the drain of the N channel FET device 3. The N channel FET device 2 has its drain connected to the drain of the N channel FET device 3, and its source connected to ground potential. The gates of the FET devices 1 and 2 are connected in common to the first binary input value A. A second P channel FET device 4 has its source connected to the A input and its drain connected in common with the source of the N channel FET device 3 at the output C. The gates of the N channel FET device 3 and the P channel device 4 are connected in common to the other binary input B.

The following truth table illustrates the operation of the circuit shown in the figure. Truth Table

A B C

1 1 0

0 0 0(V(TP))

0 1 1(V-V(TN))

1 0 1.

It is seen that when both A and B are positive, indicating a binary 1, devices 1 and 4 are off and devices 2 and 3 are on. In this manner, ground potential at the source of the N channel FET device 2 is conducted through the N channel FET device 3 to the output node C, indicating a binary zero.

When both the binary input variables A and B are at ground potential indicating a binary zero, devices 2 and 3 are off and devices 1 and 4 are on. The ground potential at the input variable A is conduct...