CPC G11C 11/406 (2013.01) | 20 Claims |
1. An apparatus comprising:
a refresh control circuit comprising:
a first sketch circuit configured to update selected ones of a first plurality of count values based on a row address;
a second sketch circuit configured to update selected ones of a second plurality of count values based on the row address when at least one of the selected ones of the first plurality of count values exceeds a first threshold;
a targeted refresh queue configured to store the row address when a maximum of the minimum of the selected ones of the first plurality of count values and the minimum of the selected ones of the second plurality of count values exceeds a second threshold; and
a refresh address generator configured to generate a targeted refresh address based on the row address in the targeted refresh queue.
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