Browse Prior Art Database

Circuit Diagnosis and Design Analysis System

IP.com Disclosure Number: IPCOM000081955D
Original Publication Date: 1974-Sep-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 67K

Publishing Venue

IBM

Related People

Bond, GL: AUTHOR

Abstract

This is a quick and efficient technique for substituting new computer circuit functions for those which are of uncertain performance. The uncertain circuit performance stems from causes such as faulty design or potential circuit component failures.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 2

Circuit Diagnosis and Design Analysis System

This is a quick and efficient technique for substituting new computer circuit functions for those which are of uncertain performance. The uncertain circuit performance stems from causes such as faulty design or potential circuit component failures.

In a large-scale integrated (LSI) circuit configuration, assume selectively actuable gates at selected points in the LSI circuits, such as at the output of individual semiconductor chips. As illustrated in Fig. 1, semiconductor chips 10, 20 and N have gating circuits integral therewith and conductive lines for enabling or disabling the various gates. In normal operation, the isolation gates do not isolate semiconductor chips from each other and the circuit performs its intended function. However, in the case of uncertain or faulty operation, probe assembly 30 contacts the pads at the input and output of a selected semiconductor chip, such as chip 20.

The probe assembly connects the circuit pads to a set of input circuits 40 and a set of output circuits 50, under the control of an external simulator/tester 60. The isolation gate of circuits being bypassed are activated to operate in the bypass mode, and the substituted circuits are appropriately programmed to provide the functions which substitute for the circuits of chip 20. The programming may use several techniques such as plug boards, read-only memory or programmable controllers. As an alternate, a substitute chip or module 70 may be connected to provide altered design functions or a maintenance replacement for the functions of chip 20. This permits functional verification prior to the removal of the doubtful chip, module or circuit function.

An alternate isolation fan-out technique i...