Apparatuses and methods for distributing row hammer refresh events across a memory device

• US 10,490,251 B2
• Filed: 01/30/2017
• Issued: 11/26/2019
• Est. Priority Date: 01/30/2017
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Wolff, Gregg D.
• Primary Examiner(s): Hidalgo, Fernando
• Application Number:
  US15/419,590
• Publication Number:
  US 20180218767A1
• Time in Patent Office: 1,030 Days
• Field of Search: 365222, 36518511, 365189011, 36523001, 36523003, 36523006
• CPC Class Codes: G06F 13/1636 using refresh
• CPC Class Codes: G06F 13/1689 Synchronisation and timing concerns synchronisation on a memory bus G06F13/4234
• CPC Class Codes: G11C 11/40611 External triggering or timing of internal or partially internal refresh operations, e.g. auto-refresh or CAS-before-RAS triggered refresh
• CPC Class Codes: G11C 11/40615 Internal triggering or timing of refresh, e.g. hidden refresh, self refresh, pseudo-SRAMs
• CPC Class Codes: G11C 11/40618 Refresh operations over multiple banks or interleaving
• CPC Class Codes: G11C 11/408 Address circuits
• CPC Class Codes: G11C 11/4096 Input/output [I/O] data management or control circuits, e.g. reading or writing circuits, I/O drivers or bit-line switches
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

Apparatuses and methods for distributing row hammer refresh events across a memory device is disclosed. In one embodiment, the present disclosure is directed to an apparatus that includes a first memory configured to receive a sequential series of refresh commands and to replace a first of the sequential refresh commands with a row hammer refresh operation once during a refresh steal cycle, a second memory configured to receive the sequential series of refresh commands at to replace a second of the sequential refresh command with a row hammer refresh operation once during a refresh steal cycle, wherein the first of the sequential refresh commands and the second of the sequential refresh commands are different commands.

Claims

1. An apparatus comprising:

a first group of chips and a second group of chips, the first group of chips including a first chip and a second chip, the first chip including a first memory array, the second chip including a second memory array;

wherein one refresh event of first and second refresh events is performed for each chip of the first and second chips, the first refresh event is based, at least in part, on an internal counter signal, and the second refresh event is based, at least in part, on a first refresh command,

wherein the first refresh command is supplied in common to the first and second chips of the first group of chips to cause the first chip to perform a first refresh operation for the first refresh event on a plurality of first memory cells in at least one bank of a plurality of first banks in the first memory array and the second chip to perform a second refresh operation for the second refresh event on a plurality of second memory cells in at least one bank of a plurality of second banks in the second memory array,

wherein the plurality of first memory cells are different in number than the plurality of second memory cells,

wherein each of the first and second refresh events is performed based, at least in part, on a token signal received from an external controller,

wherein the first refresh event is performed when the token signal is asserted by the external controller, and

wherein the second refresh event is performed when the toke signal is not asserted by the external controller.

2. The apparatus of claim 1, wherein a second refresh command is supplied in common to the first chip and the second chip to cause the first chip to perform a third refresh operation on a plurality of third memory cells in the first memory array and the second chip to perform a fourth refresh operation on a plurality of fourth memory cells in the second memory array, the plurality of third memory cells being different in number than the plurality of fourth memory cells.

3. The apparatus of claim 2, wherein the first refresh command is issued a plurality of times at first intervals, the second refresh command being issued a plurality of times at second intervals, and the first intervals being equal to the second intervals.

4. The apparatus of claim 2, wherein a third refresh command is issued in common to the first chip and the second chip to cause each of the first chip and the second chip to perform a fifth refresh operation on each of a plurality of fifth memory cells in the first memory array and a plurality of sixth memory cells in the second memory array, the plurality of fifth memory cells being equal in number to the plurality of sixth memory cells.

5. The apparatus of claim 4, wherein the first refresh command is issued a plurality of times at first intervals, the second refresh command being issued a plurality of times at second intervals, the third refresh command is issued a plurality of times at third intervals, and the first intervals being equal to the second intervals and different from the third intervals.

6. The apparatus of claim 2, wherein the first chip comprises a first refresh address storing circuit configured to store a first address corresponding to the plurality of first memory cells in the first memory array, the plurality of first memory cells in the first memory array are different in number than the plurality of second memory cells in the second memory array, the second chip comprises a second refresh address storing circuit configured to store a second address corresponding to the plurality of fourth memory cells in the second memory array, the plurality of fourth memory cells in the second memory array are different in number than the plurality of third memory cells in the first memory array, and the first address and the second address are provided externally.

7. The apparatus of claim 1, wherein the one refresh event of first and second refresh events performed for each chip of the first and second chips is based, at least in part, on an external signal.

8. An apparatus comprising:

a plurality of chips including a first chip having a first memory array, the plurality of chips further including a second chip having a second memory array,

wherein one refresh event of first and second refresh events is performed for each chip of the first chip and the second chip,

wherein, for the first refresh event, a plurality of first memory cells in at least one bank of a plurality of first banks in the first memory array of the first chip are refreshed based, at least in part, on an internal counter signal,

wherein, for the second refresh event, the second chip is configured to perform, based, at least in part, on a refresh command supplied in common to the first and second chips of the plurality of chips, a second refresh operation on a plurality of second memory cells in at least one bank of a plurality of second banks in the second memory array,

wherein the plurality of first memory cells are different in number than the plurality of second memory cells,

wherein each of the first and second refresh events is performed based, at least in part, on a token signal received from an external controller,

wherein the first refresh event is performed when the token signal is asserted by the external controller, and

wherein the second refresh event is performed when the toke signal is not asserted by the external controller.

9. The apparatus of claim 8, wherein the one refresh event of first and second refresh events performed for each chip of the first and second chips is based, at least in part, on an external signal, and

wherein the refresh command supplied in common to the first and second chips of the plurality of chips in the second refresh event is included in a plurality of refresh commands received from an external controller.

10. The apparatus of claim 8, wherein the first refresh event includes a first type of refresh event and the second refresh event includes a second type of refresh event.