IP Library Granted Patent US 10,504,577
Granted Patent B1
US 10,504,577 · App. 16/181,117 · Granted Dec 10, 2019

Apparatus with a row hit rate/refresh management mechanism

Inventor: Joshua E. Alzheimer (Boise, ID)
Assignee: Micron Technology, Inc.
G11C11/406G06F3/0604G06F3/0659G06F3/0673G11C11/4091
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Quick Facts
Patent No.
US 10,504,577
App. No.
16/181,117
Granted
Dec 10, 2019
Kind
B1
Abstract

The apparatus includes: a row hammer refresh (RHR) circuit configured to: steal a first stolen cycle to implement an RHR operation or a portion thereof, and steal a second stolen cycle after one or more operating cycles, the second stolen cycle to implement the RHR operation or a different portion thereof.

Claims (56)

1. An apparatus, comprising:

a row hammer refresh (RHR) circuit configured to:

receive a command to perform a refresh operation on a portion of a memory array,

steal a first stolen cycle of the refresh operation to implement a first portion of a RHR operation, and

steal a second stolen cycle of the refresh operation to implement a second portion of the RHR operation, the second stolen cycle being subsequent to and non-adjacent to the first stolen cycle; and

a memory array operably coupled to the RHR circuit, the memory array configured to:

implement the first portion of the RHR operation during the first stolen cycle,

implement the refresh operation or a portion thereof after the first stolen cycle, and

implement the second portion of the RHR operation during the second stolen cycle after implementing the refresh operation or a portion thereof.

2. The apparatus of claim 1 , wherein the memory array is configured to implement a different portion of the scheduled refresh operation after implementing the second portion of the RHR.

3. The apparatus of claim 1 , wherein the RHR circuit is configured to delay a predetermined number of operating cycles between stealing the first stolen cycle and the second stolen cycle.

4. The apparatus of claim 3 , wherein the RHR circuit is configured to separate the first stolen cycle and the second stolen cycle by one operating cycle.

5. The apparatus of claim 4 , wherein the RHR circuit is configured to steal a first operating cycle and a third operating cycle of an overall memory refresh sequence.

6. The apparatus of claim 1 , further comprising an address adjuster circuit operably coupled to the RHR circuit, the address adjuster circuit configured to:

receive a refresh address corresponding to a location of the memory array associated with the scheduled refresh operation;

receive an RHR address corresponding to a different location of the memory array associated with the RHR operation; and

generate an adjusted address based on the refresh address and the RHR address, the adjusted address to replace the refresh address for one or more operating cycles.

7. The apparatus of claim 6 , wherein:

the refresh address and the RHR address each corresponds to one or more sense amplifiers;

when the refresh address and the RHR address correspond to accessing a recurring sense-amplifier over consecutive operating cycles, the address adjuster circuit is configured to generate the adjusted address that separates access to the recurring sense-amplifier by one or more operating cycles between the accessing cycles.

8. The apparatus of claim 7 , wherein the address adjuster circuit includes an XNOR logic device to generate the adjusted address based on implementing an XNOR operation on the refresh address and the RHR address.

9. The apparatus of claim 1 , wherein:

the memory array is configured to store segments of electrical charges, wherein each of the segments of electrical charges represent a data value;

the scheduled refresh operation is implemented to refresh memory locations according to a schedule or an external command; and

the RHR operation is implemented to refresh victim locations adjacent to a hammered row, wherein the hammered row is a set of locations in the memory array that has been accessed more than a threshold number of times during one or more memory operations.

10. The apparatus of claim 1 , wherein the apparatus comprises a Dynamic Random-Access Memory (DRAM) device.

11. A method of operating an apparatus, the method comprising:

stealing a first stolen cycle of an overall memory refresh sequence that refreshes charges stored at specific locations in a memory array, the first stolen cycle to implementing a first portion of a row hammer refresh (RHR) operation;

delaying one or more operating cycles to implement a scheduled refresh operation or a portion thereof during the one or more operating cycles following the first stolen cycle; and

stealing a second stolen cycle after the one or more operating cycles, the second stolen cycle to implement the second portion of the RHR operation.

12. The method of claim 11 , further comprising:

implementing the first portion of the RHR operation during the first stolen cycle;

implementing the scheduled refresh operation or a portion thereof during the one or more operating cycles between the first stolen cycle and the second stolen cycle; and

implementing the second portion of the RHR operation during the second stolen cycle following the one or more operating cycles.

13. The method of claim 12 , further comprising implementing a different portion of the scheduled refresh operation after the second stolen cycle.

14. The method of claim 11 , wherein delaying the one or more operating cycles after the first stolen cycle includes delaying a predetermined number of operating cycles.

15. The method of claim 11 , wherein:

stealing the first stolen cycle includes stealing a first cycle of the overall memory refresh sequence; and

stealing the third stolen cycle includes stealing a third cycle of the overall memory refresh sequence.

16. The method of claim 11 , further comprising:

determining a refresh address corresponding to a location of the memory array associated with the scheduled refresh operation;

determining an RHR address corresponding to a different location of the memory array associated with a row hammer event and the RHR operation; and

generating an adjusted address based on the refresh address and the RHR address, the adjusted address to adjust activation of memory row in the refresh address for one or more operating cycles.

17. The method of claim 16 , wherein:

the refresh address and the RHR address each corresponds to one or more sense amplifiers, wherein the refresh address and the RHR address includes a recurring sense-amplifier; and

generating the adjusted address includes generating the adjusted address that separates access to a recurring sense-amplifier by one or more operating cycles when the refresh address and the RHR address correspond to accessing a recurring sense-amplifier over consecutive operating cycles.

18. The method of claim 17 , wherein generating the adjusted address includes implementing an XNOR operation on the refresh address and the RHR address.

19. An apparatus, comprising:

a row hammer refresh (RHR) circuit configured to:

steal a first stolen cycle to implement an RHR operation or a portion thereof, and

steal a second stolen cycle after one or more operating cycles, the second stolen cycle to implement the RHR operation or a different portion thereof; and

an address adjuster circuit operably coupled to the RHR circuit, the address adjuster circuit configured to:

receive a refresh address corresponding to a location of the memory array associated with a scheduled refresh operation, wherein at least a portion of the scheduled refresh operation corresponds to the one or more operating cycles between the first stolen cycle and the second stolen cycle;

receive an RHR address corresponding to a different location of the memory array associated with the RHR operation; and

generate an adjusted address based on the refresh address and the RHR address, the adjusted address to replace the refresh address for one or more operating cycles.

20. The apparatus of claim 19 , wherein the address adjuster circuit comprises an XNOR device.

Assignments (5)
RELEASE OF SECURITY INTEREST Recorded Nov 15, 2019
From: JPMORGAN CHASE BANK, N.A., AS COLLATERAL AGENT
To: MICRON TECHNOLOGY, INC.
Reel/Frame 051041/0317 →
RELEASE OF SECURITY INTEREST Recorded Oct 14, 2019
From: MORGAN STANLEY SENIOR FUNDING, INC., AS COLLATERAL AGENT
To: MICRON TECHNOLOGY, INC.
Reel/Frame 050724/0392 →
SUPPLEMENT NO. 12 TO PATENT SECURITY AGREEMENT Recorded Apr 19, 2019
From: MICRON TECHNOLOGY, INC.
To: MORGAN STANLEY SENIOR FUNDING, INC., AS COLLATERAL AGENT
Reel/Frame 048948/0677 →
SUPPLEMENT NO. 3 TO PATENT SECURITY AGREEMENT Recorded Apr 19, 2019
From: MICRON TECHNOLOGY, INC.
To: JPMORGAN CHASE BANK, N.A., AS COLLATERAL AGENT
Reel/Frame 048951/0902 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Nov 5, 2018
From: ALZHEIMER, JOSHUA E.
To: MICRON TECHNOLOGY, INC.
Reel/Frame 047415/0255 →
Cited By (4)
US 12,431,180 US 12,640,183 US 12,693,965 US 12,718,862