Memory with programmable refresh order and stagger time
Memory devices and systems with programmable refresh order and stagger times are disclosed herein. In one embodiment, a memory device includes a first memory bank group and a second memory bank group. The memory device is configured, in response to a refresh command, to perform a first refresh operation on the first memory bank group at a first time and a second refresh operation on the second memory bank group at a second time after the first time. The memory device is further configured to perform, in response to a read or write command, a read or write operation on the first memory bank group, the second memory bank group, or both the first and second memory bank groups after beginning the first refresh operation and before completing the second refresh operation.
1. A method comprising:
in response to a refresh command:
performing a first refresh operation on a first memory region of a memory device at a first time, and
performing a second refresh operation on a second memory region of the memory device at a second time after the first time;
receiving an access command after receiving the refresh command; and
performing, in response to the access command, an access operation on the first memory region, the second memory region, or both the first memory region and the second memory region, after beginning the first refresh operation and before completing the second refresh operation.
2. The method of claim 1 , further comprising, in response to the refresh command, offsetting the second time from the first time by a stagger time programmed into one or more mode registers of the memory device.
3. The method of claim 1 , further comprising, in response to the refresh command, performing the first and second refresh operations in accordance with an order programmed into one or more mode registers of the memory device and/or specified by one or more command address bits of the refresh command.
4. The method of claim 1 , wherein:
the first refresh operation and the second refresh operation each include a row hammer refresh (RHR) operation; and
the method further comprises initiating the RHR operation of the first refresh operation and initiating the RHR operation of the second refresh operation at different times using one or more array timers of the memory device.
5. The method of claim 1 , wherein the access operation is a first access operation, and wherein the method further comprises performing a second access operation on the second memory region during the first refresh operation.
6. The method of claim 1 , wherein performing the access operation includes performing the access operation on the first memory region during the second refresh operation.
7. An apparatus, comprising:
a memory array including a first memory region and a second memory region, wherein the apparatus is configured to:
perform, in response to a refresh command, a first refresh operation on the first memory region at a first time and a second refresh operation on the second memory region at a second time after the first time, and
perform, in response to an access command, an access operation on the first memory region, the second memory region, or both the first and second memory regions after beginning the first refresh operation and before completing the second refresh operation.
8. The apparatus of claim 7 , further comprising one or more mode registers, wherein:
one or more bits of the one or more mode registers are programmable to define a stagger time between the first time and the second time; and
in response to the refresh command, the apparatus is further configured to:
read the one or more bits of the one or more mode registers to determine the stagger time, and
offset the second time from the first time by the stagger time.
9. The apparatus of claim 7 , further comprising one or more mode registers, wherein:
one or more bits of the one or more mode registers are programmable to define an order in which the first memory region and the second memory region are to be refreshed in response to the refresh command; and
in response to the refresh command, the apparatus is further configured to:
read the one or more bits of the one or more mode registers to determine the order, and
perform the first and second refresh operations in accordance with the order.
10. The apparatus of claim 7 , wherein:
the refresh command includes a plurality of command address bits;
one or more command address bits of the plurality of command address bits specify an order in which the first memory region and the second memory region are to be refreshed in response to the refresh command; and
in response to the refresh command, the apparatus is further configured to:
read the one or more command address bits to determine the order, and
perform the first and second refresh operations in accordance with the order.
11. The apparatus of claim 7 , wherein the apparatus is configured to perform the access operation on the second memory region during the first refresh operation.
12. The apparatus of claim 11 , further comprising one or more array timers, wherein:
the first refresh operation includes a row hammer refresh (RHR) operation; and
the apparatus is further configured to, in response to the refresh command, initiate the RHR operation using the one or more array timers.
13. The apparatus of claim 12 , wherein:
the RHR operation is a first RHR operation;
the second refresh operation includes a second RHR operation; and
the apparatus is further configured to, in response to the refresh command, initiate the second RHR operation using the one or more array timers.
14. The apparatus of claim 13 , wherein the apparatus is configured to:
use a first array timer of the one or more array timers to initiate the first RHR operation; and
use a second array timer of the one or more array timers different from the first array timer to initiate the second RHR operation.
15. The apparatus of claim 7 , wherein the apparatus is configured to perform the access operation on the first memory region during the second refresh operation.
16. The apparatus of claim 7 , wherein the refresh command is a refresh all banks command (REFab).
17. The apparatus of claim 7 , wherein the apparatus is a single memory die.
18. A system, comprising:
a memory controller; and
a memory device in communication with the memory controller, wherein the memory device includes a first memory region and a second memory region, and
wherein:
the memory controller is configured to issue a refresh command to the memory device instructing the memory device to refresh both the first memory region and the second memory region,
in response to the refresh command, the memory device is configured to:
perform a first refresh operation on the first memory region at a first time; and
perform a second refresh operation on the second memory region at a second time after the first time, and
the memory device is further configured to perform an access operation on the first memory region, the second memory region, or both the first and second memory regions after beginning the first refresh operation and before completing the second refresh operation.
19. The system of claim 18 , wherein:
the memory device further includes one or more mode registers;
the memory controller is further configured to program one or more bits of the one or more mode registers to set a stagger time between the first time and the second time; and
in response to the refresh command, the memory device is further configured to offset the second time from the first time by the stagger time.
20. The system of claim 18 , wherein:
the memory controller is further configured to:
program one or more bits of one or more mode registers of the memory device to set an order in which the first memory region and the second memory region are to be refreshed in response to the refresh command, or
program one or more command address bits of the refresh command to set the order; and
in response to the refresh command, the memory device is further configured to:
read the one or more bits of the one or more mode registers and/or read the one or more command address bits of the refresh command to determine the order, and
perform the first and second refresh operations in accordance with the order.