Storage device and method of operating the same

Abstract

This disclosure relates to a storage device and a method of operating the storage device. A storage device includes: a non-volatile memory device including a target memory region; and a controller configured to control the non-volatile memory device to perform a read operation on the target memory region, configured to determine whether at least one of a plurality of adjustment conditions is satisfied for the access operation performed on the target memory region, and configured to determine a read count increment corresponding to the read operation based on the at least one adjustment condition. The plurality of adjustment conditions includes a first adjustment condition, in which a small variability between read temperatures is determined based on an index of the variability of read temperatures of a predetermined number of recent read operations performed during the access operations.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2024-0188911, filed on December 17, 2024, with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to storage devices, including memory devices. Background Technology

[0004] A storage device stores data provided by an external device based on write requests from that external device. A storage device also provides data stored in the storage device to an external device based on read requests from that external device. An external device is an electronic device capable of processing data and can be included in computers, digital cameras, mobile phones, etc. A storage device can be embedded in an external device or can be fabricated in a separate device that operates via electrical coupling to the external device. A storage device can include a memory device for storing data. Summary of the Invention

[0005] In one embodiment, a storage device may include: a non-volatile memory device including a target memory region; and a controller configured to control the non-volatile memory device to perform a read operation on the target memory region, configured to determine whether at least one of a plurality of adjustment conditions is satisfied for the access operation performed on the target memory region, and configured to determine a read count increment corresponding to the read operation based on the at least one adjustment condition. The plurality of adjustment conditions may include a first adjustment condition, in which the variability between read temperatures is determined based on an index of the variability of read temperatures of a predetermined number of recent read operations performed during the access operations.

[0006] In one embodiment, a method of operating a storage device may include: controlling a non-volatile memory device to perform a read operation on a target memory region; for each access operation performed on the target memory region, determining whether at least one of a plurality of adjustment conditions is satisfied; and determining a read count increment corresponding to the read operation based on the at least one adjustment condition. The plurality of adjustment conditions may include a first adjustment condition, in which the variability between read temperatures is determined based on an index of the variability of read temperatures during a predetermined number of recent read operations.

[0007] In one embodiment, a method of operating a storage device may include: performing one or more access operations on a target memory region by the memory device; determining the characteristics of one or more performance index curves, wherein the one or more performance index curves may include one or more of a performance index curve for erase temperature, a performance index curve for programming temperature, and a performance index curve for read temperature; determining one or more performance index values ​​corresponding to one or more access temperatures for performing the one or more access operations based on the one or more performance index curves; determining a read count increment based on one or more ratios of a reference performance index value to one or more performance index values; and performing a management operation on the target memory region based on the read count increased by the read count increment.

[0008] In one embodiment, a method includes: performing multiple access operations on a target memory region of a memory device; determining the characteristics of multiple performance index curves; determining a performance index value corresponding to an access temperature at which the multiple access operations are performed based on the multiple performance index curves; determining a read count increment based on a ratio of a reference performance index value to a performance index value; and performing a management operation on the target memory region based on the read count increased by the read count increment. Attached Figure Description

[0009] Figure 1 This is a block diagram illustrating a storage device according to one embodiment.

[0010] Figure 2 It is a table including adjustment values ​​for read count increments according to one embodiment.

[0011] Figure 3 This is a flowchart illustrating a method of operating a controller according to one embodiment.

[0012] Figure 4 and Figure 5 This is a flowchart illustrating a method for determining whether adjustment conditions for the read count increment are met according to one embodiment.

[0013] Figure 6 This is a flowchart illustrating a method for determining the read count increment according to one embodiment.

[0014] Figure 7A , Figure 7B and Figure 7C This includes a graph of read counts versus temperature according to one embodiment. Detailed Implementation

[0015] Embodiments of the present technology are described in detail with reference to the accompanying drawings. Specific structural or functional descriptions of the embodiments are provided as examples to illustrate the concepts disclosed in this application. Examples or embodiments of the concepts can be implemented in various forms, and the scope of this disclosure is not limited to the examples or embodiments described in this specification.

[0016] Temperature can significantly impact the operational performance and reliability of storage devices. High temperatures can degrade data retention characteristics by accelerating charge leakage within the memory cells. Low temperatures can degrade programming and reading performance by reducing current flow. Storage devices can utilize various correction schemes corresponding to temperature changes to establish stable performance. Storage devices can perform various management operations to prevent and mitigate potential data errors or corruption when subjected to abnormal or extreme temperature environments.

[0017] Figure 1 This is a block diagram illustrating a storage device 100 according to one embodiment.

[0018] Storage device 100 stores data received from an external host device (not shown) based on write requests from that host device. Storage device 100 sends data stored in storage device 100 to the host device based on read requests from the host device.

[0019] Storage device 100 includes memory device 110 and controller 120.

[0020] Memory device 110 stores data under the control of controller 120 and outputs the data stored in memory device 110 to controller 120. Memory device 110 performs access operations under the control of controller 120, including accessing memory regions where data is stored. Access operations include programming operations, reading operations, and erasing operations. Memory device 110 includes multiple memory regions MR where data is stored.

[0021] Controller 120 controls memory device 110. Based on write requests from the host device, controller 120 stores data sent by the host device in memory device 110. Based on read requests from the host device, controller 120 reads data from memory device 110 and sends the read data to the host device.

[0022] Controller 120 performs management operations on memory device 110 to extend the lifespan of memory device 110 and improve data reliability. Management operations include wear leveling, garbage collection, reprogramming, and parameter tuning. Parameter tuning operations include adjusting various operating voltages (such as read voltage, programming voltage, verification voltage, pass voltage, precharge voltage, and erase voltage), reference voltages, reference values, initial values, timing, and offset values ​​used during the operation of memory device 110. For example, controller 120 performs management operations independently of the host device when it does not receive a request from the host device. According to one embodiment, controller 120 performs management operations based on a request from the host device.

[0023] Controller 120 performs management operations based on read count 125. For example, controller 120 performs a management operation whenever read count 125 is greater than a predetermined reference value. The term "predetermined" includes a value established before the parameter is used during a process or algorithm, for example, when the parameter is used in relation to timing, time, conversion algorithm, preamble, edge, interval code, level, or voltage level. According to one embodiment, the value of the parameter is determined before the process or algorithm begins. According to another embodiment, the value of the parameter is determined while the process or algorithm is in progress, but before the parameter is used during the process or algorithm. Controller 120 increments read count 125 for each read operation performed by memory device 110.

[0024] High-temperature environments can degrade or worsen data retention characteristics by accelerating charge leakage within memory cells. Low-temperature environments can degrade the programming and reading performance of memory devices by reducing current flow. Controller 120 uses temperature-compensated read count increments.

[0025] Figure 2 This is a table including adjustment values ​​for the read count increment, according to one embodiment. Figure 2 In this context, each adjustment value a1, a2, b1, c1, and c2 is, for example, a value greater than 1.

[0026] refer to Figure 2 The temperature range is divided into a hot temperature range (HT), a normal temperature range (NT), and a cold temperature range (CT). Depending on the embodiment, the number of temperature ranges may vary.

[0027] To apply temperature correction to the read count increment, an adjustment value for the read count increment is determined based on at least one of the programmed temperature and the read temperature. According to one embodiment, the adjustment value may be a weighted multiplication of the read count increment by a default or base value (such as 1).

[0028] For example, when the programming temperature is included in the hot temperature range HT and the read temperature is included in the cold temperature range CT for the target memory region to which a read operation is performed, the adjustment value can be determined as a2. In this example, the read count increment is determined to be the default value multiplied by a2.

[0029] For example, when the programming temperature is in the thermal temperature range HT and the read temperature is in the normal temperature range NT for the target memory region to which a read operation is performed, the adjustment value is determined to be 1. In this example, the read count increment is determined to be the default or base value. For example, when the programming temperature is in the thermal temperature range HT and the read temperature is in the normal temperature range NT for the target memory region to which a read operation is performed, the read count increment is not adjusted, and the read count increment is determined to be the default or base value.

[0030] When the variability between erase temperature, programming temperature, and read temperature is large, the data stability of the target memory region is degraded. Conversely, when the variability between repeated read temperatures for the target memory region is small, the data stability of the target memory region is degraded. According to previous methods, because only the temperature range within which each access temperature of the target memory region falls is determined in order to determine the read count increment, the variability between access temperatures may not be properly incorporated into temperature compensation.

[0031] When the read count increment is large, the read count 125 quickly reaches the predetermined reference value for the management operation, so the management operation is performed before the data is corrupted. Performing management operations too frequently can cause problems such as performance degradation of storage device 100 or increased power consumption. Therefore, appropriate temperature compensation is applied to achieve the desired read count increment.

[0032] refer to Figure 1 To determine the read count increment for each read operation performed by memory device 110 on a target memory region, controller 120 determines whether a predetermined adjustment condition is met. When the predetermined adjustment condition is not met, controller 120 determines a default value, such as 1, as the read count increment. When the predetermined adjustment condition is met, controller 120 determines the value obtained by applying an adjustment value to the default value as the read count increment. For example, the adjustment value could be a weight multiplied by the default value. Alternatively, the adjustment value could be a value applied to the default value according to one of various arithmetic operations.

[0033] To determine predetermined adjustment conditions, controller 120 references the access temperatures at which access operations are performed on the target memory region. Access temperatures include the erase temperature at which the most recent erase operation is performed on the target memory region, referred to as the "latest erase temperature." Access temperatures include the programming temperature at which the most recent programming operation is performed on the target memory region, referred to as the "latest programming temperature." Access temperatures include the read temperature at which a predetermined number of recent read operations are performed on the target memory region, referred to as the "recent read temperature." The read temperature at which the most recent read operation is performed on the target memory region is referred to as the "latest read temperature." The most recent read operation performed on the target memory region is a read operation that triggers or increments the read count. Reference Figures 3 to 7C The method described is to determine the read count increment by referencing the access temperature using controller 120.

[0034] According to one embodiment, the controller 120 counts or tracks read counts 125 in units of memory regions included in the memory device 110 (e.g., pages, word lines, memory blocks, groups of memory blocks, planes, memory dies, memory chips, etc.).

[0035] Storage device 100 may include PCMCIA cards, smart media cards, memory sticks, various multimedia cards (such as MMC, eMMC, RS-MMC and MMC-micro), secure digital (SD) cards (such as SD, Mini-SD and Micro-SD), universal flash storage (USF) or solid-state drives (SSD).

[0036] The memory device 110 may include NAND flash memory, NOR flash memory, resistive random access memory (RRAM), phase change memory (PRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), or spin-transfer torque random access memory (STT-RAM).

[0037] Figure 3 This is a flowchart illustrating a method of operating a controller 120 according to one embodiment. The processes in the flowchart can be executed in different orders and can include... Figure 3 Compared to the processes described and illustrated in the text, there are fewer or no additional processes.

[0038] refer to Figure 3 The controller 120 controls the S110 non-volatile memory device to perform a read operation on the target memory region.

[0039] Controller 120 determines whether at least one of a plurality of adjustment conditions is met with respect to the access operation performed by S120 on the target memory region. (Reference) Figure 4 and Figure 5 Describe the method for determining whether the adjustment conditions are met.

[0040] When it is determined that at least one adjustment condition is met in S120, the method continues, wherein the controller 120 determines the value obtained in S130 by applying the adjustment value to the default value as the read count increment. The adjustment value can be any real number, including negative values. (Reference) Figure 6 Describe the method for determining the read count increment.

[0041] When it is determined that S120 does not meet at least one adjustment condition, the controller 120 determines S140 or establishes a default value as the read count increment.

[0042] Figure 4 and Figure 5 This is a flowchart illustrating a method by which controller 120 determines whether adjustment conditions for a read count increment are met according to one embodiment. The processes in the flowchart can be executed in different sequences and can include... Figure 4 Compared to processes described and illustrated in a flowchart, there are fewer or no additional processes. Processes in a flowchart can be executed in different orders and can include processes from other flowcharts. Figure 5 Compared to the processes described and illustrated in the text, there are fewer or no additional processes.

[0043] refer to Figure 4 The controller 120 determines a variability index, also known as a variability index, of the read temperature (referred to as "recent read temperature") of a predetermined number of recent read operations performed by S210 on the target memory region. The predetermined number can be two or more. The predetermined number of read operations repeatedly apply stress to the target memory region. The variability index includes at least one of the following: standard deviation, mean absolute deviation, variance, the ratio of minimum to maximum value, and the difference between the minimum and maximum values.

[0044] The controller 120 determines whether the variability between the recently read temperatures (S220) is small based on a variability index of the recently read temperatures. For example, if the variability index, which is directly proportional to the variability, is less than a predetermined reference value, the controller 120 determines that the variability is small. Conversely, if the variability index, which is inversely proportional to the variability, is greater than a predetermined reference value, the controller 120 determines that the variability is small.

[0045] When it is determined that the variability between the recently read temperatures of S220 is small, the controller 120 determines that S230 meets the first adjustment condition.

[0046] When it is determined that the variation between the recently read temperatures of S220 is large, the controller 120 determines that S240 does not meet the first adjustment condition.

[0047] refer to Figure 5In operation S310, controller 120 determines a variability index of the access temperature (referred to as the "selected access temperature") of the selected access operation performed by S310 on the target memory region. The selected access temperature includes the latest erase temperature, the latest programming temperature, and the read temperature at which the first read operation on the target memory region was performed after the latest programming operation in a previously performed programming operation. The variability index or variability indicator includes at least one of the following: standard deviation, mean absolute deviation, variance, the ratio of minimum to maximum value, and the difference between minimum and maximum values.

[0048] The controller 120 determines whether the variability between the selected access temperatures in S320 is large based on a variability index of the selected access temperature. For example, when the variability index, which is directly proportional to the variability, is greater than a predetermined reference value, the controller 120 determines that the variability is large. For example, when the variability index, which is inversely proportional to the variability, is less than a predetermined reference value, the controller 120 determines that the variability is large.

[0049] When it is determined that the variation between the selected access temperatures of S320 is large, the controller 120 determines that S330 meets the second adjustment condition.

[0050] When it is determined that the variation between the selected access temperatures of S320 is small or negligible, the controller 120 determines that S340 does not meet the second adjustment condition.

[0051] According to one embodiment, in Figure 3 In one embodiment, controller 120 determines only whether S120 satisfies the first adjustment condition among the adjustment conditions. In another embodiment, controller 120 determines only whether S120 satisfies the second adjustment condition among the adjustment conditions. In yet another embodiment, controller 120 determines whether S120 satisfies both the first and second adjustment conditions. Three or more adjustment conditions may be used.

[0052] According to one embodiment, temperature compensation can be applied to the read count increment by taking into account the variability between access temperatures of the target memory region.

[0053] Figure 6 This is a flowchart illustrating a method by which a controller 120 determines the read count increment according to one embodiment.

[0054] refer to Figure 6 The controller 120 determines one or more performance index values ​​of S410 corresponding to one or more access temperatures, and performs one or more selected access operations at the one or more access temperatures during access operations performed on the target memory region.

[0055] According to one embodiment, one or more access temperatures for performing one or more access operations include one or more of the latest erase temperature, the latest programming temperature, and the latest read temperature. To determine one or more performance index values, the controller 120 refers to one or more relationships between temperature and performance index values, which can be represented as performance index curves for erase temperature, for programming temperature, and for read temperature. For example, the performance index curve for erase temperature indicates the performance index value corresponding to the erase temperature.

[0056] According to one embodiment, the performance index is an index that indicates the performance of the memory device 110, and may include read license count, error rate, number of error bits, timing tolerance, voltage tolerance, etc.

[0057] The controller 120 determines the adjustment value of S420 for the read count increment based on one or more ratios of a predetermined reference performance index value to one or more performance index values.

[0058] According to one embodiment, the controller 120 determines an adjustment value function in a predetermined adjustment value function based on which adjustment condition is met, and determines the adjustment value of the read count increment by including one or more ratios in the determined adjustment value function.

[0059] According to one embodiment, controller 120 determines an adjustment value for the read count increment based on one or more selected ratios, excluding one or more unselected ratios. For example, the one or more unselected ratios include a ratio of a reference performance index value to a performance index value determined based on one or more performance index curves where the absolute value of the slope is less than a predetermined reference value. When the absolute value of the slope is less than the predetermined reference value, it indicates that the corresponding performance index curve is almost independent of the access temperature, and therefore the corresponding ratio is negligible.

[0060] The controller 120 determines the value obtained by S430 by applying the adjustment value to the default value as the read count increment.

[0061] Figures 7A to 7C This includes a graph of read permission count versus temperature, according to one embodiment.

[0062] refer to Figures 7A to 7C The read license count is used as a performance metric. Figure 7A Curve G1 in the figure indicates the relationship between the read permission count and the erase temperature. Figure 7B Curve G2 in the figure indicates the relationship between the read permission count and the programming temperature, and Figure 7CCurve G3 in the graph indicates the relationship between read license count and read temperature. Curves G1, G2, and G3 are included in the performance index curves illustrated in the performance index graph. Read license count refers to the number of read operations that, for example, data stored in a memory cell can withstand the effects of read interference. Curve G1 indicates the read license count and erase temperature. Curve G2 indicates the read license count and programming temperature. Curve G3 indicates the read license count and read temperature.

[0063] At least one characteristic represents each of curves G1, G2, and G3 and is stored in a separate storage area of ​​memory device 110. The characteristic of each curve includes, for example, various mathematical properties or relationships describing the form and changes of the curve, such as slope, intercept, curvature, increase / decrease, symmetry, inflection point, extremum, endpoints, etc. The characteristic of each curve can be determined during the manufacturing process of memory device 110 or by performing test operations on memory device 110 by controller 120. According to one embodiment, controller 120 periodically updates the characteristics of each curve G1, G2, and G3. Controller 120 reads one or more characteristics of each curve stored in memory device 110 and uses one or more characteristics of each curve to determine an adjustment value for the read count increment.

[0064] Each of curves G1, G2, and G3 is shown on a logarithmic scale and is linear. The relationship between read license counts and temperature, in addition to the relationships illustrated in curves G1, G2, and G3, can be utilized. The slope of curve G1 is determined from the read license counts corresponding to at least two erase temperatures. Controller 120 can determine the read license count corresponding to the latest erase temperature of the target memory region from at least any point in curve G1 and the slope of curve G1. Controller 120 can determine the read license count corresponding to the latest programming temperature of the target memory region based on curve G2. Controller 120 can determine the read license count corresponding to the latest read temperature of the target memory region based on curve G3.

[0065] When the read license count is used as a performance index, the reference read license count REF is used as a reference performance index value. The ratio of the reference read license count REF to the read license count corresponding to the latest erase temperature (referred to as the "first ratio") is determined based on Equation 1.

[0066] Equation 1: First ratio = Reference read license count REF / Read license count corresponding to the latest erase temperature.

[0067] The ratio of the reference read license count REF to the read license count corresponding to the latest programming temperature (referred to as the "second ratio") is determined based on Equation 2.

[0068] Equation 2: Second ratio = Reference read license count REF / Read license count corresponding to the latest programming temperature.

[0069] The ratio of the reference read license count REF to the read license count corresponding to the latest read temperature (referred to as the "third ratio") is determined based on Equation 3.

[0070] Equation 3: Third ratio = Reference read license count REF / Read license count corresponding to the latest read temperature.

[0071] The adjustment value for the read count increment is determined based on the adjustment value function f1 in Equation 4.

[0072] Equation 4: Adjustment value for reading the count increment = f1(first ratio, second ratio, third ratio).

[0073] According to one embodiment, the adjustment value for the read count increment is determined based on one or more selected ratios among a first ratio, a second ratio, and a third ratio, and not based on one or more unselected ratios among the first ratio, the second ratio, and the third ratio. Therefore, the adjustment value function f1 utilizes one or more selected ratios during the read count increment determination period, and does not utilize one or more unselected ratios during the read count increment determination period. The one or more unselected ratios may be a ratio of a reference read license count REF to a read license count determined based on a curve among curves G1, G2, and G3, where the absolute value of the slope is less than a predetermined reference value. For example, when the absolute value of the slope in curve G1 is less than a predetermined reference value, the first ratio of the adjustment value function f1 is not used, and the adjustment value for the read count increment is determined based on the second and third ratios, but not based on the first ratio.

[0074] According to one embodiment, the first ratio of the adjustment value function f1 is not used, and the adjustment value function f1 is the product of the second and third ratios. For example, when the read license count corresponding to the latest programming temperature PT1 is 1 million in curve G2, the read license count corresponding to the latest read temperature RT1 is 3 million in curve G3, and the reference read license count REF is 1.5 million, the adjustment value for the read count increment is 0.75, for example, 1.5M / 1M*1.5M / 3M. When the adjustment value for the read count increment is a weight multiplied by a default value (such as 1) for the read count increment, the read count increment is 0.75, for example, 1*0.75.

[0075] According to one embodiment, the first ratio of the adjustment value function f1 is not used, and the adjustment value function f1 is determined to be the third ratio subtracted from the second ratio. For example, when the read license count corresponding to the latest programming temperature PT1 is 1 million, the read license count corresponding to the latest read temperature RT1 is 3 million, and the reference read license count REF is 1.5 million, the adjustment value for the read count increment is 1, for example, 1.5M / 1M-1.5M / 3M. When the adjustment value for the read count increment is a weight multiplied by a default value (such as 1) of the read count increment, the read count increment is 1, for example, 1*1.

[0076] According to one embodiment, depending on which adjustment condition is met, controller 120 determines the adjustment value for the read count increment based on an adjustment value function other than adjustment value function f1. For example, controller 120 uses adjustment value function f1 when only the first adjustment condition is met, controller 120 uses adjustment value function f2 when only the second adjustment condition is met, and controller 120 uses adjustment value function f3 when both the first and second adjustment conditions are met.

[0077] According to one embodiment, when using performance indices other than read license counts to determine the adjustment value for read count increments, controller 120 uses curves of other performance indices and a method similar to that used with read license counts to determine the adjustment value for read count increments.

[0078] According to embodiments of this disclosure, the storage device and its operation method can enhance data retention and system performance reliability through the appropriate application of a temperature correction mechanism.

[0079] The concept has been disclosed in conjunction with examples and embodiments. Those skilled in the art will understand that various modifications, additions, combinations, and substitutions are possible without departing from the scope and technical concept of this disclosure. The embodiments disclosed in this specification should be considered from an illustrative rather than a restrictive perspective. Therefore, the scope of this disclosure is not limited to these descriptions. All changes within the meaning and scope of equivalents of the claims are included within its scope.

Claims

1. A storage device, comprising: A non-volatile memory device, which includes a target memory region; as well as A controller configured to control the non-volatile memory device to perform a read operation on the target memory region, configured to determine whether at least one of a plurality of adjustment conditions is satisfied for the access operation performed on the target memory region, and configured to determine a read count increment corresponding to the read operation based on the at least one adjustment condition. The plurality of adjustment conditions include a first adjustment condition in which the variability between read temperatures is determined based on a variability index of the read temperature of a predetermined number of recent read operations performed in the access operation.

2. The storage device according to claim 1, The plurality of adjustment conditions further include a second adjustment condition, in which the variability between access temperatures is determined based on a plurality of access temperature variability indices for performing at least one selected access operation among the access operations; and The plurality of access temperatures include the erase temperature for performing the latest erase operation in the access operation, the programming temperature for performing the latest programming operation in the access operation, and the read temperature for performing the first read operation after the programming operation in the access operation.

3. The storage device of claim 1, wherein the variability index includes at least one of the following: standard deviation, mean absolute deviation, variance, ratio of minimum to maximum value, and difference between minimum and maximum value.

4. The storage device of claim 1, wherein the controller is configured to: Based on which adjustment condition is satisfied among the plurality of adjustment conditions, an adjustment value function is determined from among a plurality of predetermined adjustment value functions; and The adjustment value for the read count increment is determined based on the adjustment value function.

5. The storage device of claim 1, wherein the controller is configured to: Based on at least one of the multiple adjustment conditions, determine one or more performance index values ​​corresponding to one or more access temperatures for performing at least one selected access operation among the access operations. The adjustment value is determined based on one or more ratios of the reference performance index value to one or more of the performance index values. as well as The value obtained by applying the adjustment value to the default value is determined as the read count increment.

6. The storage device of claim 5, wherein the one or more access temperatures include one or more of the following: an erase temperature for performing the latest erase operation, a programming temperature for performing the latest programming operation, and a read temperature for performing the read operation.

7. The storage device of claim 5, wherein the controller is configured to determine one or more performance index values ​​by utilizing the characteristics of one or more performance index curves among the performance index curves for erase temperature, performance index curves for programming temperature, and performance index curves for read temperature.

8. The storage device according to claim 7, The controller is configured to determine the adjustment value based on one or more selected ratios of the one or more ratios; and One or more of the unselected ratios include the ratio of the reference performance index value to the performance index value determined based on a performance index curve whose absolute slope is less than the reference value.

9. The storage device of claim 1, wherein the controller is configured to: determine a default value as the read count increment based on determining that at least one of the plurality of adjustment conditions is not met.

10. The storage device of claim 1, wherein the controller is configured to: Increment the read count by the read count increment; and Management operations are performed on the target memory region based on the read count.

11. A method of operating a storage device, the method comprising: Control the non-volatile memory device to perform a read operation on the target memory region; For an access operation performed on the target memory region, determine whether at least one of a plurality of adjustment conditions is satisfied; as well as Based on the at least one adjustment condition, determine the read count increment corresponding to the read operation; The plurality of adjustment conditions include a first adjustment condition in which the variability between read temperatures is determined to be small based on a variability index of read temperatures performed on a predetermined number of recent read operations.

12. The method according to claim 11, The plurality of adjustment conditions includes a second adjustment condition, in which the variability among the plurality of access temperatures is determined based on a variability index of the access temperature during the execution of at least one selected access operation; and The plurality of access temperatures include the erase temperature for performing the latest erase operation, the programming temperature for performing the latest programming operation, and the read temperature for performing the first read operation after the programming operation.

13. The method of claim 11, wherein the variability index includes at least one of the following: standard deviation, mean absolute deviation, variance, ratio of minimum to maximum value, and difference between minimum and maximum value.

14. The method of claim 11, wherein determining the read count increment comprises: Based on which adjustment condition is satisfied among the plurality of adjustment conditions, the adjustment value function is determined from among a plurality of predetermined adjustment value functions; as well as The adjustment value for the read count increment is determined based on the adjustment value function.

15. The method of claim 11, wherein determining the read count increment comprises: Based on at least one of the multiple adjustment conditions, determine one or more performance index values ​​corresponding to one or more access temperatures for performing at least one selected access operation among the access operations. The adjustment value is determined based on one or more ratios of the reference performance index value to one or more of the performance index values. as well as The value obtained by applying the adjustment value to the default value is determined as the read count increment.

16. The method of claim 15, wherein the one or more access temperatures include one or more of the following: an erase temperature at which the latest erase operation is performed, a programming temperature at which the latest programming operation is performed, and a read temperature at which the read operation is performed.

17. The method of claim 15, wherein determining the one or more performance index values ​​comprises utilizing the characteristics of one or more performance index curves among performance index curves for erase temperature, performance index curves for programming temperature, and performance index curves for read temperature.

18. The method according to claim 17, Determining the adjustment value includes determining the adjustment value based on one or more selected ratios from the one or more ratios; and One or more of the unselected ratios include the ratio of the reference performance index value to the performance index value determined based on a performance index curve whose absolute slope is less than the reference value.

19. The method of claim 11, wherein determining the read count increment comprises: Based on the determination that at least one of the plurality of adjustment conditions is not met, a default value is determined as the read count increment.

20. The method of claim 11, further comprising: Increment the read count by the read count increment; as well as Management operations are performed on the target memory region based on the read count.

21. A method of operating a storage device, the method comprising: One or more access operations are performed by the memory device on the target memory region; Determine the characteristics of one or more performance index curves, wherein the one or more performance index curves include one or more of a performance index curve for erase temperature, a performance index curve for programming temperature, and a performance index curve for read temperature. Based on the one or more performance index curves, determine one or more performance index values ​​corresponding to one or more access temperatures during the execution of the one or more access operations; The read count increment is determined based on one or more ratios of the reference performance index value to the one or more performance index values; as well as Based on the read count incremented by the read count, management operations are performed on the target memory region.

22. The method of claim 21, wherein the one or more access temperatures include one or more of the following: an erase temperature for performing the latest erase operation, a programming temperature for performing the latest programming operation, and a read temperature for performing the latest read operation.

23. The method according to claim 21, Determining the read count increment includes determining an adjustment value for the read count increment based on one or more selected ratios from the one or more ratios; and One or more of the unselected ratios include the ratio of the reference performance index value to the performance index value determined based on a performance index curve whose absolute slope is less than the reference value.

24. The method of claim 21, further comprising: Tests are performed on the memory device at different access temperatures to determine the characteristics of the one or more performance index curves.

25. The method of claim 21, further comprising: The characteristics of the one or more performance index curves are read from the memory device.

26. The method of claim 21, wherein the performance index of the performance index curve includes one of the following: read license count, error rate, number of error bits, timing tolerance, and voltage tolerance.

27. A method comprising: Perform multiple access operations on the target memory region of the memory device; Determine the characteristics of multiple performance index curves; Based on the multiple performance index curves, determine the performance index value corresponding to the access temperature for performing the multiple access operations; The read count increment is determined based on the ratio of the reference performance index value to the performance index value; as well as Based on the read count incremented by the read count, management operations are performed on the target memory region.

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