Patent attributes
N out of every M number of refresh commands are ignored (filtered out) by a buffer chip on a memory module. N and M are programmable. The buffer receives refresh commands (e.g., auto-refresh commands) from the command-address channel, but does not issue a proportion of these commands to the DRAMs on the module. This reduces the power consumed by refresh operations. The buffer may replace some auto-refresh (REF) commands with activate (ACT) and precharge (PRE) commands directed to specific rows. These rows may have known ‘weak’ cells that require refreshing more often than a majority of the other rows on the module (or component). By ignoring some auto-refresh commands, and directing some others to specific rows that have ‘weak’ cells, the power consumed by refresh operations can be reduced.
