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Avalanche Region Diode Logic

IP.com Disclosure Number: IPCOM000098579D
Original Publication Date: 1959-Apr-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Logue, JC: AUTHOR [+2]

Abstract

Diode logic is performed with Zener diodes operating around their reverse breakdown points. Operation at this point results in faster switching speeds than are attainable utilizing forward conduction operation because minority carrier storage delay is eliminated.

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Avalanche Region Diode Logic

Diode logic is performed with Zener diodes operating around their reverse breakdown points. Operation at this point results in faster switching speeds than are attainable utilizing forward conduction operation because minority carrier storage delay is eliminated.

In the two-level circuits illustrated in the upper portion of the drawing, D1, D2, Dn are biased to be normally conducting in their avalanche or reverse breakdown region. A positive pulse on any one input of the AND circuit switches the diode to its off condition. No change, however, at the output line occurs until inputs are present on all input lines simultaneously. In the OR operation, a positive input on any oneline biases all the other diodes to their off condition. The output line, therefore, rises with an input on any one or more input lines. The Zener diodes DT, which are provided to effect signal level restoration, can be omitted if desired.

The use of the avalanche technique permits operation with more than two signal levels. The circuits in the middle portion of the drawing are examples of this multi-level operation and the associated truth tables at the bottom of the drawing show the various outputs available for various combinations of inputs. The addition of a further diode enables the truth tables to be manipulated, as shown by the MODIFIED OR.

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