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Browse Prior Art Database

Logic Circuit

IP.com Disclosure Number: IPCOM000093252D
Original Publication Date: 1967-Jul-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Berding, AR: AUTHOR

Abstract

Hot-carrier diodes are used in place of resistors in this high-speed logic circuit. In the left-hand circuit, diodes D1...D4 form a positive And with a forward drop of approximately 0.3 volt. With any one of the inputs A...N at the down level of 0.1 volts, the base of T1 is held to 0.4 volts. This keeps T1 cut off. When all the inputs A...N are at the up level of 0.7 volts, current through hot-carrier diode D5 nows into the base of T1 to turn it on. The current to T1 is fed from hot-carrier diode D6 which, like D5, functions much like a current source. When T1 is on, the output voltage is 0.1 to 0.2 volts.

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Logic Circuit

Hot-carrier diodes are used in place of resistors in this high-speed logic circuit. In the left-hand circuit, diodes D1...D4 form a positive And with a forward drop of approximately 0.3 volt. With any one of the inputs A...N at the down level of 0.1 volts, the base of T1 is held to 0.4 volts. This keeps T1 cut off. When all the inputs A...N are at the up level of 0.7 volts, current through hot-carrier diode D5 nows into the base of T1 to turn it on. The current to T1 is fed from hot- carrier diode D6 which, like D5, functions much like a current source. When T1 is on, the output voltage is 0.1 to 0.2 volts.

When any one of the inputs A...N is down, T1 is held off and the current through D6 nows through the diode-corrected T2. The latter clamps the output voltage to a maximum of 0. 7 volts.

The right-hand circuit includes an inverter stage T3. Diode D7 prevents saturation of transistor T1. Diodes D5, D6, and D8 are high reverse current diodes, such as gold-silicon, and are used as current sources.

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