Browse Prior Art Database

FET Memory With Hidden Refresh

IP.com Disclosure Number: IPCOM000050669D
Original Publication Date: 1982-Dec-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Basilico, AR: AUTHOR [+2]

Abstract

A memory that requires refresh has a four-bit counter that counts from 0000 to 1111. The counter is reset to zero when a memory refresh operation is performed, and it is incremented by 1 for each memory cycle time. A decoder at the output of the counter detects three conditions: the first eight counts (0000 to 0111), the next seven counts (1000 to 1110), and count fifteen (1111). During the first eight cycles, memory refresh is inhibited. During the next seven cycles, a memory refresh operation is performed (and the counter is reset to 0000) if the memory is not busy with a normal memory access. On count = 1111, normal access to the memory is inhibited and a memory refresh operation takes place.

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FET Memory With Hidden Refresh

A memory that requires refresh has a four-bit counter that counts from 0000 to 1111. The counter is reset to zero when a memory refresh operation is performed, and it is incremented by 1 for each memory cycle time. A decoder at the output of the counter detects three conditions: the first eight counts (0000 to 0111), the next seven counts (1000 to 1110), and count fifteen (1111). During the first eight cycles, memory refresh is inhibited. During the next seven cycles, a memory refresh operation is performed (and the counter is reset to 0000) if the memory is not busy with a normal memory access. On count = 1111, normal access to the memory is inhibited and a memory refresh operation takes place. Thus, many refreshes will take place during a cycle when the memory is not otherwise being accessed, and these refresh operations will not interfere with the normal operation of the memory. Inhibiting the refresh during cycles 0 to 7 establishes the minimum time between successive refresh operations when the memory is not heavily used.

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