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Compare Equal Checking for Semiconductor Chips

IP.com Disclosure Number: IPCOM000052988D
Original Publication Date: 1981-Aug-01
Included in the Prior Art Database: 2005-Feb-12
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Homan, ME: AUTHOR

Abstract

The reliability of systems composed of semiconductor chips can be improved by providing duplicate chips and compare-equal checking of the outputs of pairs of identical chips.

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Compare Equal Checking for Semiconductor Chips

The reliability of systems composed of semiconductor chips can be improved by providing duplicate chips and compare-equal checking of the outputs of pairs of identical chips.

The figure shows a chip arrangement for compare-equal checking of two identical semiconductor chips 9 and 9' in which the logic to perform the compare- equal check function is located on each chip. As shown in the figure, the logic which achieves the compare-equal check function comprises a bidirectional driver receiver (Bi-Di) 10 and an exclusive-OR circuit 11 for all outputs, plus common OR circuit 12, and driver 13.

A signal D which is generated on each chip is supplied to driver input 10D of Bi-Di 10 and one input of exclusive-OR circuit 11. The output of the exclusive- OR circuit 11 is supplied to the check terminal 14 through OR-gate 12 and driver
13.

The output D-Out of Bi-Di 10 is connected to output pin 16 of the chip. Output pins 16 and 16' of the pair of chips are dot-ORed together so that D-Out is supplied to the receiver portion of Bi-Di 10', while D'-Out is supplied to the receiver portion of Bi-Di 10. The check output pins 14 and 14' are also dot-ORed together.

When check signals C and C' are absent, check output line 17 will be 0, which indicates that all D-Out and D'-Out are equal. When check signal C or C' is present, check output line 17 will be a 1, indicating that D-Out and D'-Out are different and one is in error. Check ter...