Storage device and operating method of memory controller
Provided are a storage device and an operating method of a memory controller. The storage device includes a non-volatile memory that outputs data from selected memory cells based on read voltage information, the read voltage information including a start read voltage, an end read voltage, and a read command. Moreover, the storage device includes a memory controller that determines whether a search region defined by the start read voltage and the end read voltage is within a multi-peak region of a threshold voltage distribution corresponding to a first state of the selected memory cells, based on the search region being within the multi-peak region, change the search region, and based on the search region not being within to the multi-peak region, determine a new read voltage using the search region.
1. A storage device comprising:
a non-volatile memory configured to output data from selected memory cells based on read voltage information, the read voltage information comprising a start read voltage, an end read voltage, and a read command; and
a memory controller configured to:
determine whether a search region defined by the start read voltage and the end read voltage is within a multi-peak region of a threshold voltage distribution corresponding to a first state of the selected memory cells,
based on the search region being within the multi-peak region, change the search region, and
based on the search region not being within to the multi-peak region, determine a new read voltage using the search region.
2. The storage device of claim 1 , wherein the memory controller is further configured to:
determine whether the search region is within a reference region,
based on the search region being within the reference region, determine whether the search region is within the multi-peak region, and
based on the search region not being within the reference region, move the search region by calculating the start read voltage and the end read voltage by a shift voltage.
3. The storage device of claim 1 , wherein the memory controller is further configured to:
count a number of memory cells having threshold voltages from the start read voltage to the end read voltage,
compare the number of memory cells with a first validation reference number,
based on the number of memory cells being greater than the first validation reference number, determine that the search region is within the multi-peak region, and
based on the number of memory cells being less than or equal to the first validation reference number, determine that the search region is not within to the multi-peak region.
4. The storage device of claim 1 , wherein the search region comprises a plurality of sub-search regions respectively defined by different voltages from the start read voltage to the end read voltage, and
the memory controller is further configured to:
count a number of first memory cells having threshold voltages from a first start read voltage of a first sub-search region among the plurality of sub-search regions to a first end read voltage of the first sub-search region,
compare the number of first memory cells with a second validation reference number,
based on the number of first memory cells being greater than the second validation reference number, determine that the search region is within the multi-peak region, and
based on the number of first memory cells being less than or equal to the second validation reference number, determine that the search region is not within the multi-peak region.
5. The storage device of claim 1 , wherein the memory controller is further configured to:
count a number of memory cells based on a first read voltage between the start read voltage and the end read voltage based on the search region being within the multi-peak region,
compare the number of memory cells with a reference number,
based on the number of memory cells being greater than the reference number, move the search region in a first direction by calculating the start read voltage and the end read voltage by a shift voltage, and
based on the number of memory cells is being than the reference number, move the search region in a second direction, different from the first direction, by calculating the start read voltage and the end read voltage by the shift voltage.
6. The storage device of claim 1 , wherein the memory controller is further configured to:
count a number of memory cells based on a first read voltage between the start read voltage and the end read voltage based on the search region being within the multi-peak region,
compare the number of memory cells with a reference number,
based on the number of memory cells being greater than the reference number, expand a range of the search region in a first direction by increasing one of the start read voltage and the end read voltage by the shift voltage, and
based on the number of memory cells being less than the reference number, expand the range of the search region in a second direction, different from the first direction, by increasing the other of the start read voltage and the end read voltage by the shift voltage.
7. The storage device of claim 1 , wherein the memory controller is further configured to, based on the search region being within the multi-peak region, store information on word lines connected to the selected memory cells.
8. The storage device of claim 1 , wherein the memory controller is further configured to:
determine whether the changed search region is within the multi-peak region,
based on the changed search region being within the multi-peak region, determine whether the changed search region is within a reference region, and
based on the changed search region being within to the reference region, transmit, to the non-volatile memory, a write command instructing to store data stored in a selected memory block including the selected memory cells in another memory block.
9. An operating method of a memory controller, the operating method comprising:
setting a search region defined by a start read voltage and an end read voltage;
determining whether the search region is within a multi-peak region of a threshold voltage distribution corresponding to a first state of selected memory cells among a plurality of memory cells included in a non-volatile memory;
based on the search region being within to the multi-peak region, changing the search region; and
based on the search region not being within to the multi-peak region, determining a new read voltage using the search region.
10. The operating method of claim 9 , further comprising:
determining whether the search region is within a reference region;
based on the search region being within the reference region, determining whether the search region is within the multi-peak region, and
based on the search region not being within the reference region, moving the search region by calculating the start read voltage and the end read voltage by a shift voltage.
11. The operating method of claim 9 , wherein the determining whether the search region is within the multi-peak region comprises:
counting a number of memory cells having threshold voltages from the start read voltage to the end read voltage;
comparing the number of memory cells with a first validation reference number;
based on the number of memory cells being greater than the first validation reference number, determining that the search region is within the multi-peak region; and
based on the number of memory cells being less than or equal to the first validation reference number, determining that the search region does is not within the multi-peak region.
12. The operating method of claim 9 , wherein the search region comprises a plurality of sub-search regions respectively defined by different voltages from the start read voltage to the end read voltage, and
the determining whether the search region is within the multi-peak region comprises:
counting a number of first memory cells having threshold voltages from a first start read voltage of a first sub-search region among the plurality of sub-search regions to a first end read voltage of the first sub-search region;
comparing the number of first memory cells with a second validation reference number;
based on the number of first memory cells being greater than the second validation reference number, determining that the search region is within the multi-peak region; and
based on the number of memory cells being less than or equal to the second validation reference number, determining that the search region is not within the multi-peak region.
13. The operating method of claim 9 , further comprising:
based on the search region being within the multi-peak region, counting a number of memory cells based on a first read voltage between the start read voltage and the end read voltage;
comparing the number of memory cells with a reference number;
based on the number of memory cells being greater than the reference number, moving the search region in a first direction by calculating the start read voltage and the end read voltage by a shift voltage; and
based on the number of first memory cells is being than the reference number, moving the search region in a second direction, different from the first direction, by calculating the start read voltage and the end read voltage by the shift voltage.
14. The operating method of claim 9 , further comprising storing information on word lines connected to the selected memory cells based on the search region being within the multi-peak region.
15. The operating method of claim 9 , further comprising:
determining whether the changed search region is within the multi-peak region;
based on the changed search region being within the multi-peak region, determining whether the changed search region is within a reference region; and
based on the changed search region being within to the reference region, transmitting, to the non-volatile memory, a write command instructing to store data stored in a selected memory block including the selected memory cells in another memory block.
16. A storage device comprising:
a non-volatile memory configured to output data from selected memory cells based on read voltage information comprising a start read voltage and an end read voltage and a read command; and
a memory controller configured to provide the read voltage information and the read command to the non-volatile memory, the memory controller comprising:
a first register configured to store reference region data representing a reference region;
a search region determination circuit configured to:
determine whether a search region defined by the start read voltage and the end read voltage is within the reference region, and
output search region data representing the search region within the reference region;
a second register configured to store validation reference number data representing a validation reference number;
a search region validation circuit configured to:
validate the search region of the search region data based on the search region data and the validation reference number data, and
output validation result data corresponding to a validation result and validation data corresponding to a validated search region; and
a read level determination circuit configured to determine a new read voltage using the validated search region of the validation data;
wherein the search region validation circuit is further configured to:
based on the search region being within a multi-peak region, count a number of memory cells based on a first read voltage between the start read voltage and the end read voltage;
compare the number of memory cells with a reference number;
based on the number of memory cells being greater than the reference number, move the search region in a first direction by calculating the start read voltage and the end read voltage by a shift voltage; and
based on the number of memory cells being less than the reference number, move the search region in a second direction, different from the first direction, by calculating the start read voltage and the end read voltage by the shift voltage.
17. The storage device of claim 16 , wherein the search region validation circuit is further configured to:
count a number of memory cells having threshold voltages from the start read voltage to the end read voltage,
compare the number of memory cells with the validation reference number,
based on the number of memory cells being greater than the validation reference number, determine that the search region of the search region data fails validation, and
based on the number of memory cells being less than or equal to the validation reference number, determine that the search region of the search region data passes validation.
18. The storage device of claim 16 , wherein the search region comprises a plurality of sub-search regions each defined by different voltages from the start read voltage to the end read voltage, and
the search region validation circuit is further configured to:
count a number of first memory cells having threshold voltages from a first start read voltage of a first sub-search region among the plurality of sub-search regions to a first end read voltage of the first sub-search region,
compare the number of first memory cells with the validation reference number,
based on the number of memory cells being greater than the validation reference number, determine that the search region of the search region data fails validation, and
based on the number of memory cells being less than or equal to the validation reference number, determine that the search region of the search region data passes validation.
19. The storage device of claim 16 , wherein the search region validation circuit is further configured to store information on word lines connected to the selected memory cells in the second register based on the search region being within the multi-peak region.