Apparatuses and methods for access based targeted refresh operations
Apparatuses, systems, and methods for access based targeted refresh operations. A memory bank has a first sub-bank and a second sub-bank. A refresh control circuit detects an aggressor in one of the sub-banks. Responsive to an access in the other sub-bank, the refresh control circuit performs a targeted refresh operation based on the sub-bank based on the aggressor address.
1 . An apparatus comprising:
a row hammer detector configured to detect an aggressor address and set a row hammer flag when the aggressor address is detected;
a comparator configured to compare the aggressor address to an accessed address and provide an active match signal when the aggressor address and the accessed address are in different sub-banks; and
a logic circuit configured to provide a targeted refresh command responsive to an access command when the match signal is active.
2 . The apparatus of claim 1 , further comprising a refresh address generator configured to provide a refresh address based on the aggressor address responsive to the targeted refresh command.
3 . The apparatus of claim 1 , further comprising:
a counter read/write circuit configured to receive a count value from a memory array, wherein the row hammer detector is configured to detect the aggressor address based on the count value.
4 . The apparatus of claim 3 , wherein the count value is stored in memory cells of a row associated with the count value.
5 . The apparatus of claim 3 , wherein the row hammer detector is further configured to:
change the count value and compare the changed count value to a threshold; and
responsive to the changed count value meeting or exceeding the threshold, provide the updated count value to the counter read/write circuit, and wherein the counter read/write circuit is further configured to write the updated count value to the memory array.
6 . The apparatus of claim 3 , further comprising:
a refresh address generator circuit configured to provide a reset address after the targeted refresh command,
wherein the comparator is configured to provide a reset signal when the accessed address is not in the same sub-bank as the reset address, and
wherein the counter read/write circuit is further configured to reset the count value responsive to the reset signal.
7 . The apparatus of claim 1 , further comprising a memory bank including a first sub-bank and a second sub-bank, wherein the accessed address is associated with the first sub-bank and the aggressor address is associated with the second sub-bank.
8 . The apparatus of claim 7 , wherein responsive to the accessed address a first word line is accessed in the first sub-bank while responsive to the targeted refresh command a word line is refreshed in the second sub-bank.
9 . A method comprising:
detecting an aggressor address and setting a row hammer flag when the aggressor address is detected;
comparing the aggressor address to an accessed address and providing an active match signal when the aggressor address and the accessed address are in different sub-banks; and
providing a targeted refresh command responsive to an access command when the match signal is active.
10 . The method of claim 9 , further comprising:
providing a refresh address based on the aggressor address responsive to the targeted refresh command.
11 . The method of claim 9 , further comprising:
detecting the aggressor address based on a count value provided by a memory array.
12 . The method of claim 11 , further comprising:
changing the count value and comparing the changed count value to a threshold; and
responsive to the changed count value meeting or exceeding the threshold, providing the updated count value to the memory array.
13 . The method of claim 11 , further comprising:
providing a reset address after the targeted refresh command;
providing a reset signal when the accessed address is not in the same sub-bank as the reset address, and
resetting the count value responsive to the reset signal.
14 . The method of claim 9 , wherein the accessed address is associated with a first sub-bank of a memory bank and the aggressor address is associated with a second sub-bank of the memory bank.
15 . The method of claim 14 , wherein responsive to the accessed address a first word line is accessed in the first sub-bank while responsive to the targeted refresh command a word line is refreshed in the second sub-bank.
16 . An apparatus comprising:
an aggressor detector circuit configured to activate a flag responsive to detecting an aggressor address in a sub-bank and provide the aggressor address;
a comparator configured to determine if an accessed address matches the aggressor address and issue an active match signal when the aggressor address and the accessed address are in different sub-banks;
a logic circuit configured to provide a targeted refresh signal to the sub-bank responsive to the activated flag; and
a refresh address generator configured to provide a refresh address based on a refresh signal or the targeted refresh signal.
17 . The apparatus of claim 16 , further comprising a row decoder configured to refresh one or more word lines of the sub-bank based on the refresh address.
18 . The apparatus of claim 16 , wherein the refresh address generator comprises:
a counter circuit configured to generate sequential refresh addresses as the refresh address when the refresh signal is active; and
a targeted refresh address generator configured to generate a targeted refresh address as the refresh address when the targeted refresh signal is active.
19 . The apparatus of claim 18 , wherein the sequential refresh addresses are part of a sequential refresh operation on the sub-bank with timing based on a refresh interval.
20 . The apparatus of claim 19 , wherein aggressor detector circuit is configured to identify the aggressor address based on a count value read from memory cells of the aggressor address.