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Redundant Clock Chopper

IP.com Disclosure Number: IPCOM000034413D
Original Publication Date: 1989-Feb-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Knebel, DR: AUTHOR [+2]

Abstract

A development suggests a method to insure that clock choppers used on semiconductor devices will perform properly even if defects are present. The proposal would add a redundant delay path to the chopper so that if one delay path is inoperative, the other will still function. Timing between logic gates and chips becomes critical as the number of logic circuits increase. The clock chopper (Fig. 1) was introduced as an on-chip timing generator in response to the growth of propagation delays between chips within a thermal conduction module (TCM). The chopper is a logic circuit which can automatically generate a clock pulse by supplying the input with an edge of a clock pulse. The width of the clock chopper pulse is determined by the number of delay blocks on the delay path.

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Redundant Clock Chopper

A development suggests a method to insure that clock choppers used on semiconductor devices will perform properly even if defects are present. The proposal would add a redundant delay path to the chopper so that if one delay path is inoperative, the other will still function. Timing between logic gates and chips becomes critical as the number of logic circuits increase. The clock chopper (Fig. 1) was introduced as an on-chip timing generator in response to the growth of propagation delays between chips within a thermal conduction module (TCM). The chopper is a logic circuit which can automatically generate a clock pulse by supplying the input with an edge of a clock pulse. The width of the clock chopper pulse is determined by the number of delay blocks on the delay path. During manufacturing operations, the chopper can have four unique fault classes which will affect the output of the pulse. Within each of these there are a certain number of defects related to the fault characteristics of the pulse. The "clock-not- chopped" is the major fault class.

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A "clock-not-chopped" condition may exist if the delay path is "stuck-at" a non-dominant value at the input of the reconvergent block. The output pulse will behave similarly to the clock pulse that is presented to the input of the clock chopper. The faulty pulse is as wide as the input pulse.

The proposal provides for introducing extra paths within the clock chopper shown in Fig...