COMPUTER SYSTEM AND MEMORY DEVICE

• US 20180277187A1
• Filed: 09/13/2017
• Published: 09/27/2018
• Est. Priority Date: 03/21/2017
• Status: Active Grant

• Current Assignee: Kioxia Corporation
• Original Assignee: Toshiba Memory Corporation (Kioxia Corporation)
• Inventors: Ikegami, Kazutaka, Noguchi, Hiroki, Abe, Keiko
• Granted Patent: US 10,141,038 B2
• Time in Patent Office: Days
• CPC Class Codes: G11C 11/1655 Bit-line or column circuits
• 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 11/1693 Timing circuits or methods
• CPC Class Codes: G11C 13/004 Reading or sensing circuits or methods
• CPC Class Codes: G11C 13/0061 Timing circuits or methods
• CPC Class Codes: G11C 2013/0057 Read done in two steps, e.g. wherein the cell is read twice and one of the two read values serving as a reference value

Abstract

According to one embodiment, a system includes: a device including a memory cell array, the device configured to execute first read operation of a first read method and second read operation of a second read method on the memory cell array; a processor configured to receive a first data from the device, the first data from a selected region in the memory cell array by the first read operation, configured to execute first calculation processing using the first data during the second read operation to the selected region, and configured to acquire a result of the first calculation processing by a first signal based on a comparison result of the first data and a second data, the first signal indicating that the first data is valid, and the second data from the selected region by the second read operation.

Claims

1. A computer system comprising:

a memory device including a memory cell array, the memory device configured to execute first read operation of a first read method and second read operation of a second read method on the memory cell array;

a processor configured to receive a first data from the memory device, the first data read from a selected region in the memory cell array by the first read operation, configured to execute first calculation processing using the first data during the second read operation to the selected region, and configured to acquire a result of the first calculation processing by a first signal based on a comparison result of the first data and a second data, the first signal indicating that the first data is valid, and the second data read from the selected region by the second read operation.

2. The system according to claim 1, wherein

when it is determined that the first data and the second data match based on the comparison result of the first data and the second data, the first signal is output, and

when it is determined that the first data and the second data do not match based on the comparison result of the first data and the second data, a second signal indicating that the first data is erroneous is output, and

the processor is configured to executes second calculation processing using the second data based on the second signal and configured to acquire a result of the second calculation processing.

3. The system according to claim 2, wherein

the first data includes a plurality of first data units, the second data includes a plurality of second data units,

the memory device transmits, among the second data units, at least one second data unit, corresponding to at least one first data unit including an error, to the processor, and

the processor executes the second calculation processing using the transmitted at least one second data unit.

4. The system according to claim 1, wherein

the memory device includes a comparison circuit which compares the first data and the second data.

5. The system according to claim 1, wherein

the processor includes a buffer circuit which holds the first data and a flag indicating a state of the first data, and

the flag is set to a value indicating that the first data is in a valid state based on the first signal.

6. The system according to claim 1, wherein

the memory device includes a read circuit configured to execute the first and second read operations,

the read circuit includes

a sense amplifier circuit having first and second input terminals,

a first interconnect connected between the first input terminal and the memory cell array,

a second interconnect connected between the first input terminal and the memory cell array,

a third interconnect connected to the second input terminal,

a fourth interconnect connected between the second input terminal and the memory cell array, and

a reference cell connected to the third interconnect,

in a first period, the first and second interconnects hold a potential corresponding to a first output signal from the selected region, the third interconnect holds a potential corresponding to a second output signal from the reference cell, and

in a second period after the first period, the second interconnect holds the potential corresponding to the first output signal, and the fourth interconnect holds a potential corresponding to a third output signal from the selected region.

7. The system according to claim 6, wherein

in a third period between the first period and the second period, a write current is supplied to the selected region.

8. The system according to claim 6, wherein

the selected region includes a magnetoresistive effect element as a memory element,

a first voltage is applied to the magnetoresistive effect element when the first output signal is output from the selected region, and

a second voltage higher than the first voltage is applied to the magnetoresistive effect element when the third output signal is output from the selected region.

9. The system according to claim 1, wherein

the memory device includes a read circuit configured to execute the first and second read operations,

the read circuit includes

a first sense amplifier circuit having first and second input terminals and a first output terminal,

a second sense amplifier circuit having third and fourth input terminals and a second output terminal,

a selection circuit having a fifth input terminal connected to the first output terminal, a sixth input terminal connected to the second output terminal, a third output terminal, and a control terminal to which a control signal is supplied,

a first interconnect connected between the first input terminal and the memory cell array,

a second interconnect connected to the second input terminal,

a third interconnect connected between the third input terminal and the memory cell array,

a fourth interconnect connected between the fourth input terminal and the memory cell array, and

a reference cell connected to the second interconnect, and

the selection circuit outputs either one of an output signal of the first sense amplifier circuit and an output signal of the second sense amplifier circuit from the third output terminal, based on the control signal.

10. The system according to claim 1, wherein

the first read method is a reference cell method, and the second read method is a self-reference method.

20. The device according to claim 1, wherein

the first read method is a reference cell method, and the second read method is a self-reference method.

11. A memory device comprising:

a memory cell array;

a read circuit configured to, based on a read command, read first data by first read operation of a first read method with respect to a selected region of the memory cell array and read second data by second read operation of a second read method with respect to the selected region; and

an output control circuit configured to output the first data, compare the first data and the second data, and output a first signal indicating that the first data is valid when the first data and the second data match.

12. The device according to claim 11, wherein

the output control circuit is configured to output a second signal, indicating that the first data is erroneous, when it is determined that the first data and the second data do not match based on a comparison result of the first data and the second data.

13. The device according to claim 12, wherein

when the first data and the second data match, an external device coupled to the output control circuit executes first calculation processing using the first data and acquires a result of the first calculation processing based on the first signal, and

when the first data and the second data do not match, the external device executes second calculation processing using the second data and acquires a result of the second calculation processing based on the second signal.

14. The device according to claim 11, wherein

the first data includes a plurality of first data units, the second data includes a plurality of second data units, and

the output control circuit outputs, among the plurality of second data units, at least one second data unit corresponding to at least one first data unit including an error.

15. The device according to claim 11, further comprising:

a comparison circuit configured to compare the first data and the second data.

16. The device according to claim 11, further comprising:

a read circuit configured to execute the first and second read operations,

wherein the read circuit includes

a sense amplifier circuit having first and second input terminals,

a first interconnect connected between the first input terminal and the memory cell array,

a second interconnect connected between the first input terminal and the memory cell array,

a third interconnect connected to the second input terminal,

a fourth interconnect connected between the second input terminal and the memory cell array, and

a reference cell connected to the third interconnect,

in a first period, the first and second interconnects hold a potential corresponding to a first output signal from the selected region, the third interconnect holds a potential corresponding to a second output signal from the reference cell, and

in a second period after the first period, the second interconnect holds the potential corresponding to the first output signal, and the fourth interconnect holds a potential corresponding to a third output signal from the selected region.

17. The device according to claim 16, wherein

in a third period between the first period and the second period, a write current is supplied to the selected region.

18. The device according to claim 16, wherein

the selected region includes a magnetoresistive effect element as a memory element,

a first voltage is applied to the magnetoresistive effect element when the first output signal is output from the selected region, and

a second voltage higher than the first voltage is applied to the magnetoresistive effect element when the third output signal is output from the selected region.

19. The device according to claim 11, further comprising:

a read circuit configured to execute the first and second read operations,

wherein the read circuit includes

a first sense amplifier circuit having first and second input terminals and a first output terminal,

a second sense amplifier circuit having third and fourth input terminals and a second output terminal,

a selection circuit having a fifth input terminal connected to the first output terminal, a sixth input terminal connected to the second output terminal, a third output terminal, and a control terminal to which a control signal is supplied,

a first interconnect connected between the first input terminal and the memory cell array,

a second interconnect connected to the second input terminal,

a third interconnect connected between the third input terminal and the memory cell array,

a fourth interconnect connected between the fourth input terminal and the memory cell array, and

a reference cell connected to the second interconnect, and

the selection circuit outputs either one of an output signal of the first sense amplifier circuit and an output signal of the second sense amplifier circuit from the third output terminal, based on the control signal.