Patent ID: 9275717
Filing Date: 2016-03-01
CPC Classification: G11C

Claim Text:
1. A refresh address generator comprising: a refresh sequence buffer configured to store a sequence of memory groups, each memory group including a plurality of memory cell rows; and a refresh address generating unit configured to generate a plurality of refresh row addresses according to the sequence of memory groups stored in the refresh sequence buffer, in response to a refresh signal, wherein the memory groups include a first memory group and a second memory group, wherein the refresh sequence buffer is configured to maintain a refresh sequence table having a different number of entries for the first memory group and the second memory group, and wherein the refresh address generating unit is configured to be responsive to the different number of entries for the first memory group and the second memory group to generate refresh row addresses for the first memory group and the second memory group at respectively different rates to accommodate different data retention characteristics of memory cell rows of the first memory group and memory cell rows of the second memory group.