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Browse Prior Art Database

Current Source Compensation

IP.com Disclosure Number: IPCOM000098996D
Original Publication Date: 1967-Nov-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Hoffman, WK: AUTHOR

Abstract

Drive wire 2 threads a group of cores 3 in a ferrite core memory. Read-write driver 4 is coupled to wire 2 by transformer 5 and transistors 6 and 7. For a read-write operation on cores 3 of wire 2, base driver 8 is turned on to provide base current 1 for transistors 6 and 7. Driver 4 is controlled to produce a current of one polarity in transistor 6 during the read portion of the cycle and to produce a current in the opposite polarity in transistor 7 during the write portion of the cycle.

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Current Source Compensation

Drive wire 2 threads a group of cores 3 in a ferrite core memory. Read-write driver 4 is coupled to wire 2 by transformer 5 and transistors 6 and 7. For a read- write operation on cores 3 of wire 2, base driver 8 is turned on to provide base current 1 for transistors 6 and 7. Driver 4 is controlled to produce a current of one polarity in transistor 6 during the read portion of the cycle and to produce a current in the opposite polarity in transistor 7 during the write portion of the cycle.

During a read operation, the base current applied to transistor 6 by driver 8 adds to the predetermined current level that driver 4 applies to the collector terminal of transistor 6. Thus the reed current on wire 2 is slightly larger than the current of driver 4. During a write operation, the base current of driver 8 subtracts from the current that driver 4 applies to wire 2.

A compensation current driver 9 is connected to provide a current 2I(b) that compensates for this difference in read and write currents supplied by the combination of drivers 4 and 8. Driver 9 is operated only during a write operation. In this memory, driver 4 provides uniform current levels for both read and write and the combination of the three drivers produces uniform current levels on the drive wire.

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