Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Ten Bit Refresh Address Generation in Personal Computer Systems

IP.com Disclosure Number: IPCOM000106925D
Original Publication Date: 1992-Jan-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 2 page(s) / 70K

Publishing Venue

IBM

Related People

Alderguia, A: AUTHOR [+3]

Abstract

This article describes a technique for use in a personal computer (PC) system to expand refresh control to support a tenth address and double the refresh rate in order to support dynamic RAM (DRAM) chips.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 54% of the total text.

Ten Bit Refresh Address Generation in Personal Computer Systems

       This article describes a technique for use in a personal
computer (PC) system to expand refresh control to support a tenth
address and double the refresh rate in order to support dynamic RAM
(DRAM) chips.

      Typically, a refresh address generator on a PC system generates
row addresses from row 0 to row 511 (9 bits). This limits the memory
chip to a 9 row X 9 column (1Mb chip) size.  Also, some chips require
refresh of all row addresses every 8 ms which is performed one row at
a 15 us rate.  Some of the new chips use a 10 row X 8
column design to achieve 1 Mb.  To achieve a 4 Mb chip requires a 10
row X 10 column design.  The requirement that all rows be refreshed
in 8 Ms remains, thus using these chips requires refresh at double
the current refresh rate.  Using the new chips in current system
designs presents two problems.  The refresh generator does not
provide 10 bits of row address and these chips require 1024 refreshes
every 8 Ms.

      One method of providing the required 1024 row refresh is to
double the rate of the refresh generator (refresh every 7 us instead
of every 15 us) and provide extra logic to generate the 10th row
address.  This method requires additional system bus overhead and the
refresh rate is now different depending on the type of memory chips
installed in the system.  Many software programs use the refresh
request rate of 15.2 us to monitor time-dependent...