System for a wide temperature range nonvolatile memory

• US 10,650,875 B2
• Filed: 08/21/2018
• Issued: 05/12/2020
• Est. Priority Date: 08/21/2018
• Status: Active Grant

• Current Assignee: Integrated Silicon Solution Incorporated (Uphill Investment Co.)
• Original Assignee: Spin Memory, Inc.
• Inventors: Sobey, Charles H.
• Primary Examiner(s): Mai, Son L
• Application Number:
  US16/107,352
• Publication Number:
  US 20200066320A1
• Time in Patent Office: 630 Days
• Field of Search: 365158
• CPC Class Codes: G06F 11/1048 using arrangements adapted for a specific error detection or correction feature
• CPC Class Codes: G06F 11/1068 in sector programmable memories, e.g. flash disk G06F11/1072 takes precedence
• CPC Class Codes: G11C 11/1653 Address circuits or decoders
• CPC Class Codes: G11C 11/1659 Cell access
• CPC Class Codes: G11C 11/1673 Reading or sensing circuits or methods
• CPC Class Codes: G11C 11/1675 Writing or programming circuits or methods
• CPC Class Codes: G11C 29/52 Protection of memory contents; Detection of errors in memory contents
• CPC Class Codes: G11C 7/04 with means for avoiding disturbances due to temperature effects

Abstract

A system for a nonvolatile memory for broad temperature range applications. The system includes a memory organized into an addressable memory range and comprising a plurality of memory arrays comprising memory cells wherein each memory array is configured for operation over a different temperature range, and a buffer for receiving a data word and an associated address for writing into the memory. A temperature sensor is used for sensing a current temperature of operation of the memory. A write controller is coupled to the buffer, the temperature sensor and the memory. The write controller is operable to perform a write operation that includes accessing a temperature value from the temperature sensor, selecting a selected memory array of the plurality of memory arrays that is configured for operation at the temperature value, and writing the data word, at the associated address, to the selected memory array.

Claims

1. A system comprising:

a memory organized into an addressable memory range and comprising a plurality of memory arrays comprising memory cells wherein each memory array is configured for operation over a different temperature range;

a buffer for receiving a data word and an associated address for writing into said memory;

a temperature sensor for sensing a current temperature of operation of said memory;

a write controller coupled to said buffer, said temperature sensor and said memory, said write controller operable to perform a write operation comprising;

accessing a temperature value from said temperature sensor;

selecting a selected memory array of said plurality of memory arrays that is configured for operation at said temperature value; and

writing said data word, at said associated address, to said selected memory array; and

a memory table associated with said memory, wherein said memory table is operable to store an address map for indicating which memory array of said plurality of memory arrays comprises a data word associated with a given address within said addressable memory range.

2. A system as described in claim 1 wherein said memory cells of said plurality of memory arrays comprise magnetic memory cells.

3. A system as described in claim 2 wherein said magnetic memory cells comprise Magnetic Tunnel Junction type magnetic memory cells.

4. A system as described in claim 1 further comprising a read controller coupled to said buffer, said temperature sensor and said memory, said read controller operable to perform a read operation comprising:

accessing a read address from said buffer wherein said read address is associated with said read operation;

reading contents of said memory table associated with said read address to determine a particular memory array of said plurality of memory arrays containing data associated with said read address; and

reading said particular memory array, at said read address, to obtain a data word associated with said read address.

5. A system as described in claim 1 wherein said plurality of memory arrays comprises:

a first memory array comprising a plurality of first memory cells that are fabricated to operate over a first temperature range;

a second memory array comprising a plurality of second memory cells that are fabricated to operate over a second temperature range, wherein said second temperature range is higher than said first temperature range; and

a third memory array comprising a plurality of third memory cells that are fabricated to operate over a third temperature range, wherein said third temperature range is higher than said second temperature range and wherein said second temperature range is higher than said first temperature range and wherein further a high temperature of said first temperature range and a low temperature of said second temperature range overlap and wherein further a high temperature of said second temperature range and a low temperature of said third temperature range overlap.

6. A system as described in claim 1 further comprising a management controller coupled to said memory and said temperature sensor, said management controller for performing a copy-over procedure comprising:

reading a current temperature value from said temperature sensor;

based on said current temperature value, determining that said memory has undergone a transition from operating within a first temperature range to operating within a second temperature range;

selecting a first memory array associated with said first temperature range and selecting a second memory array associated with said second temperature range; and

copying data from said first memory array over to said second memory array responsive to said transition.

7. A system as described in claim 1 further comprising a management controller coupled to said memory and said temperature sensor, said management controller for performing a copy-over procedure comprising:

reading a current temperature value from said temperature sensor;

based on said current temperature value, determining that said memory has undergone a transition from operating within a first temperature range to operating within a second temperature range;

selecting a first memory array associated with said first temperature range and selecting a second memory array associated with said second temperature range;

copying data from said first memory array over to said second memory array responsive to said transition; and

updating said address map of said memory table to indicate that said data copied from said copying is addressable using said second memory array.

8. A method of writing data to a memory system, said method comprising:

receiving a data word and an associated address for writing into said memory system, wherein said memory system is organized into an addressable memory range and comprises a plurality of memory arrays comprising memory cells wherein each memory array of said plurality of memory arrays is configured for operation over a different temperature range;

accessing a current temperature value from a temperature sensor;

selecting a selected memory array of said plurality of memory arrays that is configured for operation at said current temperature value;

writing said data word, at said associated address, to said selected memory array;

maintaining an address map within a memory table wherein said address map indicates which memory array of said plurality of memory arrays comprises a data word associated with a given address of said addressable memory range; and

responsive to said writing, updating said address map to indicate that said associated address is associated with said selected memory array.

9. A method as described in claim 8 wherein said memory cells of said plurality of memory arrays comprise magnetic memory cells.

10. A system as described in claim 9 wherein said magnetic memory cells comprise Magnetic Tunnel Junction type magnetic memory cells.

11. A method as described in claim 8 further comprising performing a read operation, said read operation comprising:

accessing a read address associated with said read operation;

reading contents of said memory table associated with said read address to determine a particular memory array of said plurality of memory arrays containing data associated with said read address; and

reading said particular memory array, at said read address, to obtain a data word associated with said read address.

12. A method as described in claim 8 wherein said plurality of memory arrays comprises:

a first memory array comprising a plurality of first memory cells that are fabricated to operate over a first temperature range;

a second memory array comprising a plurality of second memory cells that are fabricated to operate over a second temperature range, wherein said second temperature range is higher than said first temperature range; and

a third memory array comprising a plurality of third memory cells that are fabricated to operate over a third temperature range, wherein said third temperature range is higher than said second temperature range and wherein said second temperature range is higher than said first temperature range and wherein further a high temperature of said first temperature range and a low temperature of said second temperature range overlap and wherein further a high temperature of said second temperature range and a low temperature of said third temperature range overlap.

13. A method as described in claim 8 further comprising performing a copy-over procedure comprising:

reading a current temperature value from said temperature sensor;

based on said current temperature, determining that said memory has undergone a transition from operating within a first temperature range to operating within a second temperature range;

selecting a first memory array associated with said first temperature range and selecting a second memory array associated with said second temperature range; and

copying data from said first memory array over to said second memory array responsive to said transition.

14. A method as described in claim 8 further comprising performing a copy-over procedure comprising:

reading a current temperature value from said temperature sensor;

based on said current temperature, determining that said memory has undergone a transition from operating within a first temperature range to operating within a second temperature range;

selecting a first memory array associated with said first temperature range and selecting a second memory array associated with said second temperature range;

copying data from said first memory array over to said second memory array responsive to said transition; and

updating said address map to indicate that data copied from said copying is addressable by said second memory array.

15. A method of storing data in a memory system, said method comprising:

maintaining an address map of data stored in a memory system, wherein said memory system is organized into an addressable memory range and comprising a plurality of memory arrays comprising memory cells wherein each memory array of said plurality of memory arrays is configured for operation over a different temperature range and wherein further said memory system is configured to operate over a plurality of temperature ranges, and wherein said address map indicates which memory array of said plurality of memory arrays comprises a data word associated with a given address;

reading a current temperature value from a temperature sensor;

based on said current temperature value, determining that said memory system has undergone a transition from operating within a first temperature range of said plurality of temperature ranges to operating within a second temperature range of said plurality of temperature ranges;

selecting a first memory array associated with said first temperature range and selecting a second memory array associated with said second temperature range;

copying data from said first memory array over to said second memory array responsive to said transition; and

updating said memory map based on said copying.

16. A method as described in claim 15 wherein said memory cells of said plurality of memory arrays comprise magnetic memory cells.

17. A system as described in claim 16 wherein said magnetic memory cells comprise Magnetic Tunnel Junction type magnetic memory cells.

18. A method as described in claim 15 further comprising performing a read operation, said read operation comprising:

accessing a read address associated with said read operation;

reading contents of said address map associated with said read address to determine a particular memory array of said plurality of memory arrays containing data associated with said read address; and

reading said particular memory array, at said read address, to obtain a data word associated with said read address.

19. A method as described in claim 15 wherein said plurality of memory arrays comprises:

a first memory array comprising a plurality of first memory cells that are fabricated to operate over a first temperature range;

a second memory array comprising a plurality of second memory cells that are fabricated to operate over a second temperature range, wherein said second temperature range is higher than said first temperature range; and

a third memory array comprising a plurality of third memory cells that are fabricated to operate over a third temperature range, wherein said third temperature range is higher than said second temperature range and wherein said second temperature range is higher than said first temperature range and wherein further a high temperature of said first temperature range and a low temperature of said second temperature range overlap and wherein further a high temperature of said second temperature range and a low temperature of said third temperature range overlap.

20. A method as described in claim 15 further comprising performing a write operation, said write operation comprising:

accessing said temperature sensor to obtain a current temperature value;

receiving a data word and an associated address for writing into said memory system;

selecting a selected memory array of said plurality of memory arrays that is configured for operation at said current temperature value;

writing said data word, at said associated address, to said selected memory array; and

updating said address map responsive to said writing.

21. A method as described in claim 15, further comprising performing extreme error recovery by reading the data from a plurality of memory arrays and voting on a valid data value.

22. A method as described in claim 15, further comprising performing extreme error recovery by reading the data from a plurality of memory arrays and applying error correction coding to obtain a valid data.

23. A method as described in claim 15, further comprising, writing to the low-temperature array is written to first at high temperature, and based on a time value, writing from the low-temp array to a higher temperature array until a correct temperature array is reached.