Apparatuses for refreshing memory of a semiconductor device
Disclosed herein is an apparatus that includes a memory cell array, a row hammer refresh circuit configured to generate a row hammer refresh address based on an access history of the memory cell array, a redundancy circuit configured to store a plurality of detective addresses of the memory cell array, and a row pre-decoder configured to skip a refresh operation on the row hammer refresh address when the row hammer refresh address matches any one of the plurality of defective addresses.
1. An apparatus comprising:
a memory cell array;
a row hammer refresh circuit configured to generate a row hammer refresh address based on an access history of the memory cell array;
a redundancy circuit configured to store a plurality of defective addresses of the memory cell array; and
a row pre-decoder configured to skip a refresh operation on the row hammer refresh address when the row hammer refresh address matches any one of the plurality of defective addresses.
2. The apparatus of claim 1 ,
wherein the redundancy circuit is configured to compare the row hammer refresh address with the plurality of defective addresses responsive to a first refresh command, and
wherein the row pre-decoder is configured to perform the refresh operation on the row hammer refresh address responsive to a second refresh command when the row hammer refresh address does not match any one of the plurality of defective addresses.
3. The apparatus of claim 2 ,
wherein the memory cell array includes a regular array and a redundant array, and
wherein the plurality of defective addresses stored in the redundancy circuit are assigned to the regular array.
4. The apparatus of claim 3 , wherein the row pre-decoder is configured to perform the refresh operation on the row hammer refresh address when the row hammer refresh address indicates an effective address in the redundant array.
5. The apparatus of claim 4 , wherein the row pre-decoder is configured to skip the refresh operation on the row hammer refresh address when the row hammer refresh address indicates an unused address in the redundant array.
6. The apparatus of claim 5 ,
wherein the redundancy circuit includes a plurality of memory sets, each of the memory sets storing a defective address in the regular array and an enable bit that indicates the memory set is enabled or not, and
wherein the redundancy circuit is configured to compare the row hammer refresh address with the defective address in each of the memory sets when the row hammer refresh address is directed to the regular array.
7. The apparatus of claim 6 ,
wherein each of the memory sets in the redundancy circuit having a different set address, and
wherein the redundancy circuit further includes a decoder that converts the row hammer refresh address directed to the redundant array into a row hammer refresh set address, the redundancy circuit being configured to decide that the enable bit assigned to the memory set whose set address matches the row hammer refresh set address is activated or not.
8. The apparatus of claim 1 , further comprising a refresh counter configured to update a refresh address responsive to a refresh command,
wherein the row hammer refresh circuit is configured to stop updating the refresh address in the refresh counter until a row hammer refresh operation is completed.
9. An apparatus comprising:
a memory cell array;
a row hammer refresh circuit configured to generate a row hammer refresh address based on an access history of the memory cell array;
a latch circuit configured to latch the row hammer refresh address responsive to a first occurrence of a refresh command; and
a row pre-decoder configured to perform a refresh operation on the row hammer refresh address responsive to a second occurrence of the refresh command.
10. The apparatus of claim 9 ,
wherein the memory cell array includes a regular array and a redundant array,
wherein the regular array includes a normal memory cell and a defective memory cell, and
wherein the row pre-decoder is configured to perform the refresh operation on the row hammer refresh address when the row hammer refresh address is directed to the normal memory cell in the regular array.
11. The apparatus of claim 10 , wherein the row pre-decoder is configured to skip the refresh operation on the row hammer refresh address when the row hammer refresh address is directed to the defective memory cell in the regular array.
12. The apparatus of claim 11 ,
wherein the redundant array includes a used memory cell substituting the defective memory cell in the regular array and an unused memory cell, and
wherein the row pre-decoder is configured to perform the refresh operation on the row hammer refresh address when the row hammer refresh address is directed to the used memory cell in the redundant array.
13. The apparatus of claim 12 , wherein the row pre-decoder is configured to skip the refresh operation on the row hammer refresh address when the row hammer refresh address is directed to the unused memory cell in the redundant array.
14. The apparatus of claim 9 , further comprising a refresh counter configured to update a refresh address responsive to the refresh command,
wherein the row hammer refresh circuit is configured to stop updating the refresh address in the refresh counter until a row hammer refresh operation is completed.
15. The apparatus of claim 14 ,
wherein the latch circuit is configured to latch the refresh address responsive to the second occurrence of the refresh command; and
wherein the row pre-decoder is configured to perform the refresh operation on the refresh address responsive to a third occurrence of the refresh command.
16. An apparatus comprising:
a memory cell array including a regular array and a redundant array;
a redundancy circuit including a plurality of memory sets each storing a defective address in the regular array and an enable bit that indicates the memory set is enabled or not, each of the memory sets having a different set address;
a refresh counter configured to update a refresh address responsive to a refresh command; and
a row pre-decoder configured to perform a refresh operation on the refresh address when the refresh address is directed to the regular array and does not match the defective address stored in any of the memory sets in the redundancy circuit, and configured to skip the refresh operation on the refresh address when the refresh address is directed to the redundant array and when the memory set corresponding to the refresh address is not enabled.
17. The apparatus of claim 16 , wherein the row pre-decoder is configured to skip the refresh operation on the refresh address when the refresh address is directed to the regular array and matches the defective address stored in any of the memory sets in the redundancy circuit.
18. The apparatus of claim 17 , wherein the row pre-decoder is configured to perform the refresh operation on the refresh address when the refresh address is directed to the redundant array and when the memory set corresponding to the refresh address is enabled.
19. The apparatus of claim 18 , further comprising:
a row hammer refresh circuit configured to generate a row hammer refresh address based on an access history of the memory cell array; and
a selector configured to supply one of the refresh address supplied from the refresh counter and the row hammer refresh address supplied from the row hammer refresh circuit to the redundancy circuit.
20. The apparatus of claim 19 , wherein the row hammer refresh circuit is configured to stop updating the refresh address in the refresh counter until a row hammer refresh operation is completed.