Dynamically allocating number of bits per cell for memory locations of a non-volatile memory

• US 9,189,386 B2
• Filed: 03/14/2013
• Issued: 11/17/2015
• Est. Priority Date: 02/25/2010
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Wakrat, Nir Jacob, Toelkes, Tahoma M.
• Primary Examiner(s): CHOE, YONG J
• Application Number:
  US13/830,233
• Publication Number:
  US 20140019673A1
• Time in Patent Office: 978 Days
• Field of Search: 711/170
• US Class Current: 1/1
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/7202 Allocation control and policies
• CPC Class Codes: G11C 11/5628 Programming or writing circuits; Data input circuits
• CPC Class Codes: G11C 11/5642 Sensing or reading circuits; Data output circuits
• CPC Class Codes: G11C 2211/5641 Multilevel memory having cells with different number of storage levels

Abstract

Systems and methods are provided for dynamically allocating a number of bits per cell to memory locations of a non-volatile memory (“NVM”) device. In some embodiments, a host may determine whether to store data in the NVM device using SLC programming or MLC programming operations. The host may allocate an erased block as an SLC block or MLC block based on this determination regardless of whether the erased block was previously used as an SLC block, MLC block, or both. In some embodiments, to dynamically allocate a memory location as SLC or MLC, the host may provide an address vector to the NVM package, where the address vector may specify the memory location and the number of bits per cell to use for that memory location.

Claims

1. A method for programming a non-volatile memory, comprising:

receiving data to store in memory cells of the non-volatile memory;

receiving an indicator specifying a number of states per memory cell to use when programming the data to the memory cells; and

programming the data to the memory cells in a program order associated with the number of states per memory cell,

wherein the memory cells are arranged in a plurality of rows, each row comprising a group of memory cells, and the program order defines an order in which the rows are programmed within the memory,

wherein the program order for rows of memory cells having more than one state per memory cell is not sequential,

wherein first data is programmed to a first state of a first group of memory cells of a first row, followed by second data programmed to a first state of a second group of memory cells of a second row, followed later by third data programmed to a second state of the first group of memory cells of the first row.

2. The method of claim 1, wherein the program order for rows of memory cells having one state per memory cell is sequential.

3. The method of claim 1, wherein the indicator is part of the address vector for the program request.

4. A non-volatile memory, comprising:

an array of memory cells arranged in rows, each row comprising at least one page of memory cells;

an input for receiving data to store in the memory cells and an indicator specifying a number of states per memory cell to use when programming the data to the memory cells;

circuitry that programs the data to one or more pages of memory cells in a program order, the program order associated with the number of states per memory cell; and

a controller that determines the number of states per memory cell to use when programming the data based on a characteristic of the data, wherein the characteristic of the data comprises the source of the data.

5. The non-volatile memory of claim 4, wherein the program order defines an order in which the rows are programmed within the memory.

6. The non-volatile memory of claim 5, wherein the program order for rows of memory cells having one state per memory cell is sequential.

7. The non-volatile memory of claim 5, wherein the program order for rows of memory cells having more than one state per memory cell is not sequential.

8. The non-volatile memory of claim 7, wherein the circuitry programs first data to a first state of a first page of memory cells of a first row, followed by programming second data to a first state of a second page of memory cells of a second row, followed later by programming third data to a second state of the first page of memory cells of the first row.

9. The non-volatile memory of claim 4, wherein the indicator is part of an address vector for a program request.

10. An apparatus, comprising:

a non-volatile memory comprising groups of memory cells arranged in rows, the non-volatile memory receives data and programs the data to one or more groups of memory cells according to a program order associated with a number of states per memory cell; and

a controller that determines the number of states per memory cell to use when programming the data and transmits an indicator specifying the number of states per memory cell and the data to the non-volatile memory as part of a program request, wherein the program order defines an order in which the rows are programmed within the memory, wherein the program order for rows of memory cells having one state per memory cell is sequential, and wherein the program order for rows of memory cells having more than one state per memory cell is not sequential.

11. The apparatus of claim 10, wherein first data is programmed to a first state of a first group of memory cells of a first row, followed by second data programmed to a first state of a second group of memory cells of a second row, followed later by third data programmed to a second state of the first group of memory cells of the first row.

12. The apparatus of claim 10, wherein the indicator is part of an address vector of the program request.

13. The apparatus of claim 10, wherein the controller determines the number of states per memory cell to use when programming the data based on a characteristic of the data.

14. The apparatus of claim 13, wherein the characteristic of the data comprises the source of the data.