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Patent US3636518A successfully refreshed from Google Patents.
US3636518A
Expired / Lapsed
US
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Arrangement for detecting shorted diodes in selection matrices in core memories
Assignee: AG Communication Systems Corp
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Filing: 1970-03-18
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Granted: 1972-01-18
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Expires: 1990-03-18
Abstract
Abstract In a selection matrix of a memory circuit, diodes and transistors are connected to an intermediate source of voltage through resistors and sensors. Reverse voltage is thereby applied to the diodes and transistors except when they are selected for operation, and an indication of current flow by the sensors while reverse voltage is applied shows that either a diode or transistor is shorted.
Inventors
- 👤 John G Van Bosse
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:34
CPC Classifications
G; G11; G11C; G11C29/00; G11C29/04; G11C29/50; G11C29/02
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
187 words
In a selection matrix having a source of direct current, a plurality of operating conductors, a plurality of switching elements connected in a matrix between said source and said operating conductors and operable to connect said operating conductors selectively in series with said source of direct current, a plurality of diodes connected as OR gates in a buffer arrangement between said switching elements and said operating conductors, a test circuit for routinely checking said matrix for short circuits comprising: isolating resistive means connecting said operating conductors individually to said source of direct current for applying to each of said operating conductors a voltage that is intermediate the voltage of said source, current sensing means, a plurality of resistors, said current sensing means connected through each one of said resistors to one of the junctions connecting each of said switching elements to respective one of said diodes, and said sensing means connected to said source of current at a potential level that normally reverse biases said diodes whereby current flow through said sensing means while said switching elements are nonconductive indicates a short circuit between said operating conductors.
Claim 2
Dependent Claim
187 words
In a selection matrix having a source of direct current, a plurality of operating conductors, a plurality of switching elements connected in a matrix between said source and said operating conductors and operable to connect said operating conductors selectively in series with said source of direct current, a plurality of diodes connected as OR gates in a buffer arrangement between said switching elements and said operating conductors, a test circuit for routinely checking said matrix for short circuits comprising: isolating resistive means connecting said operating conductors individually to said source of direct current for applying to each of said operating conductors a voltage that is intermediate the voltage of said source, current sensing means, a plurality of resistors, said current sensing means connected through each one of said resistors to one of the junctions connecting each of said switching elements to respective one of said diodes, and said sensing means connected to said source of current at a potential level that normally reverse biases said diodes whereby current flow through said sensing means while said switching elements are nonconductive indicates a short circuit between said operating conductors.
Claim 3
Dependent Claim
63 words
In a test circuit for a selection matrix according to claim 1 wherein said operating conductors are windings of magnetic memory systems and said resistive means of saId test circuit comprises a pair of resistors for each of said windings, each resistor of said pairs being connected from one end of a respective winding to an intermediate tap of said source of current.
Claim 4
Dependent Claim
79 words
In a test circuit for a selection matrix according to claim 1 wherein said resistive means limits the current flow through said current sensing means caused by shorting of any one of said diodes to a first level of current flow substantially different from a second level of current flow through said current sensing means caused by shorting of any one of said switching elements, and said sensing means distinguishing between said first and second levels of current flow.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-17 | 1975-07-19 | 1976-01-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-17 | 1979-07-19 | 1980-01-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-17 | 1983-07-19 | 1984-01-18 | $7700.00 | Window Closed / Lapsed |