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Logic Circuit

IP.com Disclosure Number: IPCOM000094681D
Original Publication Date: 1965-Apr-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Henle, RA: AUTHOR [+2]

Abstract

This is a current switch logic circuit which incorporates tunnel rectifiers in place of passive resistance elements.

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Logic Circuit

This is a current switch logic circuit which incorporates tunnel rectifiers in place of passive resistance elements.

Tunnel rectifier D2 replaces the usual collector resistor. Tunnel rectifier D1, in combination with transistor Q4, replaces the usual emitter resistor. As indicated in the tunnel rectifier V-1 characteristic curves, rectifier D1 is operated in region 2 and serves as a constant current source. When inputs A and B are most negative, i.e., at the down level, transistor Q3 conducts. The resultant nonconduction of Q1 and Q2 forces D2 into the low-voltage state of region 1, causing output C to be at ground level.

When input A is positive at the up level, Q1 conducts. When input B is positive, Q2 conducts. Both Q1 and Q2 conduct when A and B are up. Such action directs current through D2 causing its operating point to shift from the low- voltage to the high-voltage state of region 3. This causes output C to assume its most positive or up level. Removal of all inputs results in a return to the original state.

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