DRAM data retention time, refresh interval determination method, refresh method and device

Abstract

The embodiment of the present invention provides a method for determining DRAM data retention time and refresh interval, a DRAM refresh method and device, the DRAM data retention time method comprising: obtaining a first temperature of a target DRAM in a reference state and a first minimum data retention time at the first temperature; obtaining a second minimum data retention time of the target DRAM and a second temperature corresponding to the second minimum data retention time; creating an exponential curve according to the first temperature, the first minimum data retention time, the second minimum data retention time and the second temperature; determining the current data retention time of the target DRAM at the current temperature according to the exponential curve. The technical solution of the present invention can adjust the refresh interval for refreshing the DRAM to reduce power consumption.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a method for determining a DRAM data retention time and a refresh interval, and a DRAM refresh method and device. Background Art

[0002] The principle of Dynamic Random Access Memory (DRAM) is to use the charge stored in the capacitor to store binary data. Since capacitors have leakage in reality, it is necessary to charge the capacitors periodically to prevent the information stored in them from being lost. This action of charging the capacitors in DRAM is called refresh. The time that the data in the DRAM storage unit can be kept without being lost without refresh is called the data retention time, and the data retention time is determined by the leakage current of its capacitor.

[0003] From the characteristics of semiconductor devices, the lower the temperature, the less leakage of the storage unit inside the DRAM, and the lower the required refresh frequency; conversely, the higher the temperature, the higher the required refresh frequency of the DRAM.

[0004] When setting the refresh frequency of DRAM, the CPU (central processing unit) of the existing memory system mostly adopts a fixed refresh interval, and only uses twice the refresh frequency above a certain temperature point.

[0005] A higher refresh rate will increase the power consumption of DRAM. The cells inside DRAM are quite different, so it is difficult to achieve the goal of not causing DRAM errors and not increasing DRAM power consumption.

[0006] Therefore, a new DRAM refresh method is needed.

[0007] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0008] The purpose of the embodiments of the present invention is to provide a method for determining the DRAM data retention time and refresh interval, and a DRAM refresh method and device, thereby reducing DRAM power consumption and improving bandwidth.

[0009] Other features and advantages of the present invention will become apparent from the following detailed description, or may be learned in part by practice of the present invention.

[0010] According to a first aspect of an embodiment of the present invention, a method for determining DRAM data retention time is provided, the method comprising: obtaining a first temperature of a target DRAM in a reference state and a first minimum data retention time at the first temperature; obtaining a second minimum data retention time of the target DRAM and a second temperature corresponding to the second minimum data retention time; creating an exponential curve based on the first temperature, the first minimum data retention time, the second minimum data retention time and the second temperature; and determining a current data retention time of the target DRAM at the current temperature based on the exponential curve.

[0011] In some embodiments, determining the current data retention time of the target DRAM at the current temperature based on the exponential curve includes: reading the real-time temperature measured by the internal sensor of the target DRAM at a set time interval; and determining the current data retention time of the target DRAM at the real-time temperature based on the exponential curve.

[0012] In some embodiments, before obtaining the second minimum data retention time of the target DRAM and the second temperature corresponding to the second minimum data retention time, the method also includes: determining whether the target DRAM is a new device; if so, performing a data retention time test on the target DRAM to obtain and store the second minimum data retention time of the target DRAM and the second temperature corresponding to the second minimum data retention time, and obtaining the second minimum data retention time of the target DRAM and the second temperature corresponding to the second minimum data retention time; if not, obtaining the second minimum data retention time of the target DRAM and the second temperature corresponding to the second minimum data retention time.

[0013] In some embodiments, the set time interval ranges from 2s to 5s.

[0014] In some embodiments, creating an exponential curve according to the first temperature, the first minimum data retention time, the second minimum data retention time, and the second temperature includes creating an exponential curve according to the following formula:

[0015]

[0016] in, T1 is the first temperature, T2 is the second temperature, T3 is the current temperature, RTb is the current data retention time corresponding to the current temperature, x1 is the first minimum data retention time, and x2 is the second minimum data retention time.

[0017] In some embodiments, creating an exponential curve according to the first temperature, the first minimum data retention time, the second minimum data retention time, and the second temperature includes creating an exponential curve according to the following formula:

[0018]

[0019] in, T1 is the first temperature, T2 is the second temperature, T3 is the current temperature, T4 is the temperature margin, x1 is the first minimum data retention time, and x2 is the second minimum data retention time.

[0020] In some embodiments, the temperature margin ranges from 10°C to 20°C.

[0021] In some embodiments, the first temperature is 95° C. and the first minimum data retention time is 32 ms.

[0022] According to a second aspect of an embodiment of the present invention, a method for determining a DRAM refresh interval is provided. Based on the method for determining a DRAM data retention time of the first aspect of an embodiment of the present invention, the method for determining a DRAM refresh interval further includes: determining a refresh interval setting value of a target DRAM according to a current data retention time, wherein the refresh interval setting value is less than or equal to a quotient obtained by dividing the current data retention time by the number of refreshes.

[0023] In some embodiments, the refresh interval is adjusted according to the refresh interval setting value, the refresh interval is less than or equal to the refresh interval setting value, and its accuracy is adapted to the memory controller.

[0024] In some embodiments, the refresh number is 8192 times.

[0025] According to the third aspect of the embodiments of the present invention, a DRAM refresh method is provided. Based on the method for determining the DRAM refresh interval described in the second aspect of the embodiments of the present invention, the refresh method also includes: setting a refresh interval time, and refreshing the target DRAM according to the refresh interval time, wherein the refresh interval time is not greater than the refresh interval setting value.

[0026] According to a fourth aspect of an embodiment of the present invention, a device for determining DRAM data retention time is provided, the device comprising: a first acquisition unit, used to acquire a first temperature of a target DRAM in a reference state and a first minimum data retention time at the first temperature; a second acquisition unit, used to acquire a second minimum data retention time of the target DRAM and a second temperature corresponding to the second minimum data retention time; a first creation unit, used to create an exponential curve according to the first temperature, the first minimum data retention time, the second minimum data retention time and the second temperature; and a first determination unit, used to determine a current data retention time of the target DRAM at a current temperature according to the exponential curve.

[0027] According to a fifth aspect of an embodiment of the present invention, a device for determining a DRAM refresh interval is provided, comprising the device for determining a DRAM data retention time as described in the fourth aspect of an embodiment of the present invention, the device further comprising: a second determination unit for determining a refresh interval setting value of the target DRAM based on the current data retention time, wherein the refresh interval setting value is less than or equal to a quotient obtained by dividing the current data retention time by the refresh interval.

[0028] According to the sixth aspect of an embodiment of the present invention, a DRAM refresh device is provided, comprising the device for determining the DRAM data retention time according to the fifth aspect of an embodiment of the present invention, the refresh device also comprising: a refresh unit for setting a refresh interval time and refreshing a target DRAM according to the refresh interval time, wherein the refresh interval time is not greater than the refresh interval setting value.

[0029] The technical solution provided by the embodiment of the present invention may have the following beneficial effects:

[0030] In the technical solutions provided in some embodiments of the present invention, an exponential curve with DRAM temperature and data retention time as parameters is created, and the current data retention time of the DRAM is calculated according to the current temperature, thereby reducing the refresh frequency of the DRAM at normal or low temperature, thereby reducing DRAM power consumption and improving bandwidth while ensuring DRAM function.

[0031] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings herein are incorporated into and constitute a part of the specification, showing embodiments consistent with the present invention, and together with the specification, are used to explain the principles of the present invention. Obviously, the accompanying drawings described below are only some embodiments of the present invention, and for those of ordinary skill in the art, other accompanying drawings can be obtained based on these accompanying drawings without creative work. In the accompanying drawings:

[0033] Figure 1 A flowchart of a method for determining DRAM data retention time according to an embodiment of the present invention is schematically shown;

[0034] Figure 2 A schematic diagram of an exponential curve according to an embodiment of the present invention is schematically shown;

[0035] Figure 3 A flowchart of a method for refreshing a DRAM according to another embodiment of the present invention is schematically shown;

[0036] Figure 4 A flowchart of a method for determining a DRAM refresh interval according to another embodiment of the present invention is schematically shown;

[0037] Figure 5 A flowchart of a DRAM refresh method according to another embodiment of the present invention is schematically shown;

[0038] Figure 6 A block diagram schematically shows a device for determining DRAM data retention time according to an embodiment of the present invention;

[0039] Figure 7 A block diagram schematically shows a device for determining a DRAM refresh interval according to another embodiment of the present invention;

[0040] Figure 8 A block diagram of a DRAM refresh device according to another embodiment of the present invention is schematically shown. DETAILED DESCRIPTION

[0041] The exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, the exemplary embodiments can be implemented in a variety of forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that the present invention will be more comprehensive and complete and fully convey the concepts of the exemplary embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their detailed description will be omitted.

[0042] Although relative terms such as "upper" and "lower" are used in this specification to describe the relative relationship of one component of the illustration to another component, these terms are used in this specification only for convenience, such as the direction of the examples described in the drawings. It is understood that if the modules of the illustration are flipped upside down, the component described as "upper" will become the component "lower". Other relative terms, such as "high", "low", "top", "bottom", "left", "right", etc., also have similar meanings. When a structure is "on" other structures, it may mean that the structure is formed integrally on the other structure, or that the structure is "directly" disposed on the other structure, or that the structure is "indirectly" disposed on the other structure through another structure.

[0043] The terms "a", "an", and "said" are used to indicate the presence of one or more elements / components / etc.; the terms "comprising" and "having" are used to indicate an open-ended inclusive meaning and mean that additional elements / components / etc. may be present in addition to the listed elements / components / etc.

[0044] In the related art, dynamic memory devices such as DRAM require that all rows be refreshed once per refresh interval to prevent the loss of data stored in the DRAM. The refresh interval can be 64ms. If the data is not refreshed, the charge encoding the data in the memory cell will leak away. Most DRAM rows can last for many seconds between refresh operations at high temperature limits, and can keep data for longer at typical temperatures. The short refresh interval comes from a small number of leaky memory cells. When the memory is not in use, unnecessary refreshing of all rows at the rate required by the leaky memory cells will result in a large waste of power consumption.

[0045] In order to solve the above problems, the present invention provides a solution for refreshing DRAM, by setting the refresh interval of DRAM, so as to reduce the power consumption waste of DRAM while ensuring the function of DRAM.

[0046] The technical solution of the embodiment of the present invention can be applied to DDR (Double Data Rate) DRAM, but is not limited thereto.

[0047] Figure 1 A method for determining DRAM data retention time according to an exemplary embodiment of the present invention is schematically shown. The method provided by the embodiment of the present invention can be executed by any electronic device with computer processing capabilities, such as a central processing unit. Figure 1 , the method for determining the DRAM data retention time may include the following steps:

[0048] Step S102, obtaining a first temperature of the target DRAM in a reference state and a first minimum data retention time at the first temperature;

[0049] Step S104, obtaining a second minimum data retention time of the target DRAM and a second temperature corresponding to the second minimum data retention time;

[0050] Step S106, creating an exponential curve according to the first temperature, the first minimum data retention time, the second minimum data retention time and the second temperature;

[0051] Step S108, determining the current data retention time of the target DRAM at the current temperature according to the exponential curve.

[0052] Here, in the reference state, the first temperature may be 95° C., and the first minimum data retention time may be 32 ms, that is, the minimum data retention time of the DRAM at 95° C. is 32 ms, which is a DRAM device performance requirement specified in the product standard requirements of the DRAM specified in the DDR4 protocol of the Jedec (Joint Electronic Device Engineering Council). The first temperature and the first minimum retention time are pre-stored in the memory for retrieval when needed.

[0053] The second temperature and the second minimum data retention time are the minimum data retention time of all DRAMs obtained by the CPU memory controller performing a data retention test on the connected DRAMs at room temperature. Here, the CPU memory controller can be connected to multiple DRAMs, and after the CPU memory controller performs a data retention test on these DRAMs, it obtains the data retention time corresponding to each of these DRAMs, and takes the minimum value of these data retention times as the second minimum data retention time.

[0054] In the technical solution of the embodiment of the present invention, the data retention time curve of DRAM at different temperatures is set to be in exponential form. An exponential curve is created by using a first temperature, a first minimum data retention time, a second temperature, and a second minimum data retention time. The current data retention time of the target DRAM is determined based on the exponential curve to refresh the DRAM. This can reduce the power consumption of the DRAM while ensuring the DRAM function.

[0055] During the system initialization phase, the user chooses to let the CPU perform a data retention time test on the DRAM connected to the memory controller, measure the minimum data retention time of all DRAMs under the memory channel, and record the temperature of the DRAM internal temperature sensor at this time, that is, obtain the above-mentioned second temperature and second minimum data retention time, and save the second temperature and second minimum data retention time in the memory.

[0056] Specifically, the memory controller of the CPU performs a duration test on the connected DRAM at room temperature and measures the minimum data retention time of all DRAMs at the current temperature. Here, the room temperature may be 25° C., but is not limited thereto.

[0057] In the embodiment of the present invention, the data retention time curves of the DRAM at different temperatures are set to be in an exponential form.

[0058] Based on the temperature and minimum data retention time at this time, as well as the Jedec protocol requirement of 32ms for the minimum data retention time of DRAM at 95°C, an exponential curve can be obtained to calculate the corresponding relationship between data retention time and temperature.

[0059] After the system is restarted, it is necessary to determine whether to replace the DRAM, that is, before step S104, determine whether the target DRAM is a new device to determine whether to re-test the data retention time of the DRAM.

[0060] If the target DRAM is a new device, a data retention time test is performed on the target DRAM to obtain the second minimum data retention time of the target DRAM and the second temperature corresponding to the second minimum data retention time, and the second minimum data retention time and the second temperature are stored. In step S104, the second minimum data retention time of the target DRAM and the second temperature corresponding to the second minimum data retention time are obtained.

[0061] If the target DRAM is not a new device, the second minimum data retention time of the target DRAM and the second temperature corresponding to the second minimum data retention time are directly acquired.

[0062] In this way, an exponential curve can be created according to the parameters acquired in step S102 and step S104.

[0063] Specifically, the exponential curve can be expressed by the following formula (1):

[0064]

[0065] in, T1 is the first temperature, T2 is the second temperature, T3 is the current temperature, RTb is the current data retention time corresponding to the current temperature, x1 is the first minimum data retention time, and x2 is the second minimum data retention time.

[0066] In the formulas of the embodiments of the present invention, the temperature unit is ° C. and the data retention time unit is ms.

[0067] When the first temperature is 95°C and the first minimum data retention time is 32ms, the exponential curve obtained by substituting these two parameters into the above exponential curve is:

[0068]

[0069] in, T2 is the second temperature, x2 is the second minimum data retention time, T2 and x2 are constant parameters that are measured and saved in advance, and these constant parameters can be saved in a non-volatile memory for recall, but the storage location is not limited thereto. That is, the exponential curve is a curve of RTb changing with T3.

[0070] In another embodiment of the present invention, the exponential curve can be expressed by the following formula (2):

[0071]

[0072] in, T1 is the first temperature, T2 is the second temperature, T3 is the current temperature, RTb is the current data retention time corresponding to the current temperature, T4 is the temperature margin, x1 is the first minimum data retention time, and x2 is the second minimum data retention time.

[0073] When the first temperature is 95°C and the first minimum data retention time is 32ms, the exponential curve obtained by substituting these two parameters into the above exponential curve is:

[0074]

[0075] in, T2 is the second temperature, x2 is the second minimum data retention time, the temperature margin T4 is a set constant, and both T2 and x2 are constants taken from the non-volatile memory. That is, the exponential curve is a curve of RTb changing with T3.

[0076] The temperature margin may be in the range of 10° C. to 20° C. That is, the temperature margin T4 may be 10° C., 15° C., or 20° C., and is not limited thereto.

[0077] In the existing DDR system, as shown in Table 1 below, the CPU refresh rate change to DRAM is based on 85°C. Here, TCASE is the temperature. The memory refresh interval of DRAM is obtained by dividing the DRAM data retention time by the refresh number. The refresh number is determined by the JEDEC protocol.

[0078] Table 1 Memory refresh interval table

[0079]

[0080] It can be seen that reserving a 10°C margin for the actual data retention time can improve the stability of DRAM.

[0081] Take TCASE = 95-T4. If TCASE increases by 10°C, the current data retention time will be longer, which slows down the data refresh and reduces power consumption. If TCASE decreases by 10°C, the current data retention time will be shorter, which speeds up the set data refresh and is relatively safe.

[0082] When the temperature margin is 10°C, the exponential curve is:

[0083]

[0084] in, T2 is the second temperature, x2 is the second minimum data retention time, T2 and x2 are constant parameters that are measured and saved in advance, and these constant parameters can be saved in a non-volatile memory for recall, but the storage location is not limited thereto. That is, the exponential curve is a curve of RTb changing with T3.

[0085] like Figure 2 As shown, curve 201 and curve 202 are exponential curves respectively obtained by creating the curve without considering the temperature margin and by considering the temperature margin.

[0086] Before step S108, the memory controller in the CPU needs to read the real-time temperature measured by the internal sensor of the target DRAM, and in step S108, obtain the current data retention time corresponding to the real-time temperature according to the above exponential curve.

[0087] After step S108, step S108 is executed cyclically at a set time interval, specifically including: reading the real-time temperature measured by the internal sensor of the target DRAM at a set time interval; and determining the current data retention time of the target DRAM at the real-time temperature according to the exponential curve.

[0088] Here, the value range of the set time interval is 2s to 5s, that is, the time interval can be 2s, 3s, 4s or 5s, and is not limited thereto.

[0089] After step S108, a refresh interval setting value of the target DRAM can be determined according to the current data retention time, wherein the refresh interval setting value is less than or equal to the quotient obtained by dividing the current data retention time by the number of refreshes. Here, the number of refreshes can be 8192, which can be changed according to the changes specified in the JEDEC protocol.

[0090] Specifically, after obtaining the current data retention time, the refresh interval setting value in the memory controller is calculated based on the structure of the CPU internal memory controller. The calculation principle is that the refresh interval setting value set in the memory controller cannot exceed the quotient obtained by dividing the current data retention time by the number of refreshes, that is, the refresh interval corresponding to the current data retention time.

[0091] For example, when the refresh interval corresponding to the current data retention time calculated according to the above exponential curve formula is 21.2μs, if 21μs and 21.5μs can be set in the memory controller, the refresh interval of the DRAM should be set to 21μs. Here, the precision of the refresh interval time is 0.5. Specifically, the refresh interval time can be adjusted according to the refresh interval setting value, and the refresh interval time is less than or equal to the refresh interval setting value, and its precision is adapted to the memory controller.

[0092] Here, the refresh times can be 8192 times.

[0093] Assuming that the minimum data retention time of DRAM a measured at room temperature of 20°C is 1.2s, and the minimum data retention time of DRAM b measured at room temperature of 24°C is 1.05s, then the current data retention time corresponding to each temperature obtained according to the above exponential curve taking into account the temperature margin is shown in Table 2 below.

[0094] Table 2 Correspondence between temperature and set refresh interval

[0095]

[0096] like Figure 3 As shown, an embodiment of the present invention provides a method for refreshing DRAM, comprising the following steps:

[0097] Step S301, system startup.

[0098] Step S302, determine whether a new DRAM is replaced. If yes, execute step S303, if not, execute step S305.

[0099] Step S303, testing the minimum data retention time of the DRAM.

[0100] Step S304, updating the data retention time and temperature to the storage medium.

[0101] Step S305 , reading the data retention time and temperature stored in the storage medium.

[0102] Step S306, calculating the corresponding refresh interval at each temperature.

[0103] Step S307, calculating the corresponding memory controller refresh interval setting value at each temperature.

[0104] Step S308, the CPU reads the DRAM temperature at regular intervals, updates the refresh interval setting value, and adjusts the refresh interval time.

[0105] Step S309, refresh DRAM.

[0106] like Figure 4 As shown, the method for determining the DRAM refresh interval provided in the embodiment of the present invention includes not only step S102, step S104, step S106, and step S108, but also the following steps:

[0107] Step S410, determining a refresh interval setting value of the target DRAM according to the current data retention time, wherein the refresh interval setting value is less than or equal to a quotient obtained by dividing the current data retention time by the number of refresh times.

[0108] like Figure 5 As shown, the method for determining the DRAM refresh interval provided in the embodiment of the present invention includes steps S102, S104, S106, S108, and S410, and further includes the following steps:

[0109] Step S512, setting a refresh interval time, and refreshing the target DRAM according to the refresh interval time, wherein the refresh interval time is not greater than the refresh interval setting value.

[0110] In the method for determining DRAM data retention time, the method for determining DRAM refresh interval, and the method for refreshing DRAM provided in the embodiments of the present invention, by creating an exponential curve with DRAM temperature and data retention time as parameters, and setting the current data retention time of the DRAM according to the current temperature, the refresh frequency of the DRAM at normal temperature / low temperature can be reduced, thereby reducing DRAM power consumption while ensuring DRAM function.

[0111] The following describes an apparatus embodiment of the present invention, which can be used to execute the methods of the various embodiments of the present invention described above. Figure 6 As shown, a device 600 for determining DRAM data retention time according to an embodiment of the present invention may include:

[0112] A first acquisition unit 602 is used to acquire a first temperature of a target DRAM in a reference state and a first minimum data retention time at the first temperature;

[0113] A second acquisition unit 604 is used to acquire a second minimum data retention time of the target DRAM and a second temperature corresponding to the second minimum data retention time;

[0114] A first creating unit 606, configured to create an exponential curve according to the first temperature, the first minimum data retention time, the second minimum data retention time and the second temperature;

[0115] The first creation unit 608 is configured to determine the current data retention time of the target DRAM at the current temperature according to the exponential curve.

[0116] like Figure 7 As shown, a DRAM refresh interval determination device 700 provided according to an embodiment of the present invention includes: a first acquisition unit 602, a second acquisition unit 604, a first creation unit 606, a second creation unit 608, and

[0117] The second determining unit 710 is used to determine a refresh interval setting value of the target DRAM according to the current data retention time, wherein the refresh interval setting value is less than or equal to a quotient obtained by dividing the current data retention time by the number of refresh times.

[0118] like Figure 8 As shown, a DRAM refresh device 800 provided according to an embodiment of the present invention includes: a first acquisition unit 602, a second acquisition unit 604, a first creation unit 606, a second creation unit 608, a second determination unit 710, and

[0119] The refresh unit 812 is used to set a refresh interval time and refresh the target DRAM according to the refresh interval time, and the refresh interval time is not greater than the refresh interval setting value.

[0120] Since the various functional modules of the device of the exemplary embodiment of the present invention correspond to the steps of the exemplary embodiment of the above-mentioned method, for details not disclosed in the device embodiment of the present invention, please refer to the above-mentioned embodiments of the method for determining the DRAM data retention time, the method for determining the DRAM refresh interval, and the DRAM refresh method of the present invention.

[0121] In the DRAM data retention time determination device, DRAM refresh interval determination device, and DRAM refresh device provided in the embodiments of the present invention, an exponential curve with DRAM temperature and data retention time as parameters is created, and the current data retention time of the DRAM is calculated according to the current temperature, thereby reducing DRAM power consumption while ensuring DRAM function.

[0122] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the disclosure disclosed herein. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not disclosed by the present invention. The description and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0123] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for determining DRAM data retention time, characterized in that: The method comprises: Acquire a first temperature of a target DRAM in a reference state and a first minimum data retention time at the first temperature; Acquire a second minimum data retention time of the target DRAM and a second temperature corresponding to the second minimum data retention time; creating an exponential curve based on the first temperature, the first minimum data retention time, the second minimum data retention time, and the second temperature; Determine the current data retention time of the target DRAM at the current temperature according to the exponential curve; The step of creating an exponential curve according to the first temperature, the first minimum data retention time, the second minimum data retention time, and the second temperature includes creating an exponential curve according to the following formula: ;or ; in, , T1 is the first temperature, T2 is the second temperature, T3 is the current temperature, T4 is the temperature margin, RTb is the current data retention time corresponding to the current temperature, x1 is the first minimum data retention time, and x2 is the second minimum data retention time.

2. The method according to claim 1, characterized in that: Determining the current data retention time of the target DRAM at the current temperature according to the exponential curve includes: Reading the real-time temperature measured by the internal sensor of the target DRAM at a set time interval; The current data retention time of the target DRAM at the real-time temperature is determined according to the exponential curve.

3. The method according to claim 2, characterized in that Before obtaining the second minimum data retention time of the target DRAM and the second temperature corresponding to the second minimum data retention time, the method further includes: Determining whether the target DRAM is a new device; If yes, perform a data retention time test on the target DRAM to obtain and store the second minimum data retention time of the target DRAM and the second temperature corresponding to the second minimum data retention time, and obtain the second minimum data retention time of the target DRAM and the second temperature corresponding to the second minimum data retention time; If not, then the second minimum data retention time of the target DRAM and the second temperature corresponding to the second minimum data retention time are obtained.

4. The method according to claim 2, characterized in that: The set time interval ranges from 2s to 5s.

5. The method according to claim 1, characterized in that The temperature margin ranges from 10°C to 20°C.

6. The method according to claim 1, characterized in that The first temperature is 95° C., and the first minimum data retention time is 32 ms.

7. A method for determining a DRAM refresh interval, characterized in that: Based on the method for determining the DRAM data retention time according to any one of claims 1 to 6, the method for determining the DRAM refresh interval further includes: A refresh interval setting value of the target DRAM is determined according to the current data retention time, wherein the refresh interval setting value is less than or equal to a quotient obtained by dividing the current data retention time by the number of refresh times.

8. The method according to claim 7, characterized in that The refresh interval time is adjusted according to the refresh interval setting value, wherein the refresh interval time is less than or equal to the refresh interval setting value, and its accuracy is adapted to the memory controller.

9. The method according to claim 8, characterized in that The refresh times are 8192 times.

10. A DRAM refresh method, characterized in that: The method for determining a DRAM refresh interval based on any one of claims 7 to 9 further includes: setting a refresh interval time, and refreshing a target DRAM according to the refresh interval time, wherein the refresh interval time is not greater than a refresh interval setting value.

11. A device for determining DRAM data retention time, characterized in that: include; A first acquisition unit, configured to acquire a first temperature of a target DRAM in a reference state and a first minimum data retention time at the first temperature; A second acquisition unit, configured to acquire a second minimum data retention time of the target DRAM and a second temperature corresponding to the second minimum data retention time; a first creating unit, configured to create an exponential curve according to the first temperature, the first minimum data retention time, the second minimum data retention time and the second temperature; A first determining unit, configured to determine a current data retention time of the target DRAM at a current temperature according to the exponential curve; The step of creating an exponential curve according to the first temperature, the first minimum data retention time, the second minimum data retention time, and the second temperature includes creating an exponential curve according to the following formula: ;or ; in, , T1 is the first temperature, T2 is the second temperature, T3 is the current temperature, T4 is the temperature margin, RTb is the current data retention time corresponding to the current temperature, x1 is the first minimum data retention time, and x2 is the second minimum data retention time.

12. A device for determining a DRAM refresh interval, characterized in that: The device for determining the DRAM data retention time as claimed in claim 11 further comprises: The second determining unit is used to determine a refresh interval setting value of the target DRAM according to the current data retention time, wherein the refresh interval setting value is less than or equal to a quotient obtained by dividing the current data retention time by the number of refresh times.

13. A DRAM refresh device, characterized in that: The device for determining the DRAM refresh interval as claimed in claim 12 further comprises: The refresh unit is used to set a refresh interval time and refresh the target DRAM according to the refresh interval time, and the refresh interval time is not greater than the refresh interval setting value.

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