阅读说明：本技术 非易失存性存储器中存储单元的寿命自检测方法及系统 (Method and system for self-detecting life of memory cell in nonvolatile memory ) 是由 刘德斌 雷冬梅 于 2020-12-17 设计创作，主要内容包括：本发明提供一种非易失性存储器中存储单元的寿命自检方法及系统,方法包括：控制电路接收主机发送的操作指令,触发针对目标存储单元的VT自检指令,并传递给VT自检电路；所述VT自检电路获取所述目标存储单元当前的电压Vt,若所述电压Vt小于Vth阈值,则将所述电压Vt由模拟信号转换为数字信号,并传递给寿命计算模块；所述寿命计算模块计算所述电压Vt的数字信号的哈希值作为索引号,从预设的存储寿命哈希表中查找所述索引号对应的寿命值,并反馈给所述控制电路；所述控制电路将查找到的寿命值发送给所述主机。本发明可以解决现有技术中非易失性存储器的存储单元失效时间不确定,容易导致数据丢失的问题。(The invention provides a method and a system for self-checking the service life of a storage unit in a nonvolatile memory, wherein the method comprises the following steps: the control circuit receives an operation instruction sent by the host, triggers a VT self-checking instruction aiming at the target storage unit and transmits the VT self-checking instruction to the VT self-checking circuit; the VT self-checking circuit acquires the current voltage Vt of the target storage unit, and if the voltage Vt is smaller than a Vth threshold value, the voltage Vt is converted into a digital signal from an analog signal and is transmitted to a service life calculating module; the service life calculation module calculates a hash value of the digital signal of the voltage Vt as an index number, searches a service life value corresponding to the index number from a preset storage service life hash table and feeds the service life value back to the control circuit; and the control circuit sends the searched life value to the host. The invention can solve the problems that the failure time of the storage unit of the nonvolatile memory is uncertain and the data is easy to lose in the prior art.)

1. A method for self-testing the life of a memory cell in a non-volatile memory, comprising:

the control circuit receives an operation instruction sent by the host, triggers a VT self-checking instruction aiming at the target storage unit and transmits the VT self-checking instruction to the VT self-checking circuit;

the VT self-checking circuit acquires the current voltage Vt of the target storage unit, and if the voltage Vt is smaller than a Vth threshold value, the voltage Vt is converted into a digital signal from an analog signal and is transmitted to a service life calculating module;

the service life calculation module calculates a hash value of the digital signal of the voltage Vt as an index number, searches a service life value corresponding to the index number from a preset storage service life hash table and feeds the service life value back to the control circuit;

and the control circuit sends the searched life value to the host.

2. The method of claim 1, wherein the control circuit triggers the VT self-test command when the host sends an operation command including an erase and/or write command.

3. The method of self-testing the life of a memory cell in a non-volatile memory as claimed in claim 1, wherein said VT self-test circuit comprises: the device comprises a Pump circuit, a VT measuring module and an ADC conversion module;

the Pump circuit outputs different voltages to the GATE end of the COMS tube of the target storage unit;

the VT measurement module detects a current Id of a DRAIN end of the COMS tube of the target storage unit and a voltage Vt of the COMS tube of the target storage unit, and outputs the voltage Vt to the ADC conversion module when the current Id is changed;

the ADC conversion module converts the voltage Vt from an analog signal to a digital signal and transmits the digital signal to the service life calculation module.

4. The method as claimed in claim 1, wherein the lifetime hash table is set before the non-volatile memory is shipped, and is prepared according to Vt-cycling test data of the non-volatile memory.

5. A system for self-testing the life of a memory cell in a non-volatile memory, comprising: the system comprises a control circuit, a VT self-checking circuit and a service life calculating module;

the control circuit is used for receiving an operation instruction sent by a host, generating a VT self-checking instruction aiming at a target storage unit and transmitting the VT self-checking instruction to the VT self-checking circuit;

the VT self-checking circuit is used for acquiring the current voltage Vt of the target storage unit, and if the voltage Vt is smaller than the Vth threshold value, converting the voltage Vt from an analog signal into a digital signal and transmitting the digital signal to the service life calculating module;

the service life calculation module is used for calculating a hash value of the digital signal of the voltage Vt to obtain an index number, searching a service life value corresponding to the index number from a preset storage service life hash table, and feeding back the service life value to the control circuit;

and the control circuit is used for sending the searched life value to the host.

6. The system of claim 5, wherein the control circuit triggers the VT self-test command when the host sends an operation command including an erase or write command.

7. The self-test system for life of a memory cell in a non-volatile memory as claimed in claim 5, wherein said VT self-test circuit comprises: the device comprises a Pump circuit, a VT measuring module and an ADC conversion module;

the Pump circuit is used for outputting different voltages to the GATE end of the COMS tube of the target storage unit;

the VT measurement module is used for detecting a current Id at a DRAIN end of the COMS tube of the target storage unit and a voltage Vt of the COMS tube of the target storage unit, and outputting the voltage Vt to the ADC conversion module when the current Id is changed;

the ADC conversion module is used for converting the voltage Vt from an analog signal to a digital signal and transmitting the digital signal to the service life calculation module.

8. The system as claimed in claim 5, wherein the lifetime hash table is set before the non-volatile memory is shipped, and is prepared according to the Vt-cycling test data of the non-volatile memory.

Technical Field

The present invention relates to the field of non-volatile memory technologies, and in particular, to a method and a system for self-detecting a lifetime of a memory cell in a non-volatile memory.

Background

The validity of the data stored in the nonvolatile memory has a specific age, which is generally between 10 and 20 years. The validity time of data storage of the nonvolatile memory is a test estimated value and cannot inform a host that a current storage unit fails in use, and a storage space is required to be changed, so that when the host erases data, whether the current storage unit fails or not is unknown, if data is written into the failed storage unit again, the data cannot be correctly written into the failed storage unit, and the data is lost when the failed storage unit is read again next time.

Therefore, since the failure time of the storage unit of the nonvolatile memory for storing data is uncertain, and data loss is easily caused, it is necessary to provide a method for self-detecting the lifetime of the nonvolatile memory.

Disclosure of Invention

The invention aims to provide a method and a system for self-detecting the service life of a storage unit in a nonvolatile memory, which aim to solve the problem that the storage unit of the nonvolatile memory in the prior art is uncertain in failure time and easy to cause data loss.

In order to achieve the above object, the present invention provides a method for self-checking a lifetime of a memory cell in a nonvolatile memory, comprising:

the control circuit receives an operation instruction sent by the host, triggers a VT self-checking instruction aiming at the target storage unit and transmits the VT self-checking instruction to the VT self-checking circuit;

the VT self-checking circuit acquires the current voltage Vt of the target storage unit, and if the voltage Vt is smaller than a Vth threshold value, the voltage Vt is converted into a digital signal from an analog signal and is transmitted to a service life calculating module;

the service life calculation module calculates a hash value of the digital signal of the voltage Vt as an index number, searches a service life value corresponding to the index number from a preset storage service life hash table and feeds the service life value back to the control circuit;

and the control circuit sends the searched life value to the host.

Further, in the lifetime self-checking method for the memory cell in the nonvolatile memory, when the operation command sent by the host includes an erase and/or write command, the control circuit triggers the VT self-checking command.

Further, in the method for self-checking a lifetime of a memory cell in a non-volatile memory as described above, the VT self-checking circuit includes: the device comprises a Pump circuit, a VT measuring module and an ADC conversion module;

the Pump circuit outputs different voltages to the GATE end of the COMS tube of the target storage unit;

the VT measurement module detects a current Id of a DRAIN end of the COMS tube of the target storage unit and a voltage Vt of the COMS tube of the target storage unit, and outputs the voltage Vt to the ADC conversion module when the current Id is changed;

the ADC conversion module converts the voltage Vt from an analog signal to a digital signal and transmits the digital signal to the service life calculation module.

Further, in the method for self-checking the lifetime of the memory cell in the nonvolatile memory, the memory lifetime hash table is set before the nonvolatile memory is shipped, and is created from Vt-cycling test data of the nonvolatile memory.

In order to achieve the above object, the present invention also provides a lifetime self-checking system for a memory cell in a nonvolatile memory, comprising: the system comprises a control circuit, a VT self-checking circuit and a service life calculating module;

the control circuit is used for receiving an operation instruction sent by a host, generating a VT self-checking instruction aiming at a target storage unit and transmitting the VT self-checking instruction to the VT self-checking circuit;

the VT self-checking circuit is used for acquiring the current voltage Vt of the target storage unit, and if the voltage Vt is smaller than the Vth threshold value, converting the voltage Vt from an analog signal into a digital signal and transmitting the digital signal to the service life calculating module;

the service life calculation module is used for calculating a hash value of the digital signal of the voltage Vt as an index number, searching a service life value corresponding to the index number from a preset storage service life hash table, and feeding back the service life value to the control circuit;

and the control circuit is used for sending the searched life value to the host.

Further, in the lifetime self-checking system of the storage unit in the non-volatile memory, when the operation command sent by the host includes an erase and/or write command, the control circuit triggers the VT self-checking command.

Further, in the lifetime self-test system of the memory cell in the nonvolatile memory as described above, the VT self-test circuit includes: the device comprises a Pump circuit, a VT measuring module and an ADC conversion module;

the Pump circuit is used for outputting different voltages to the GATE end of the COMS tube of the target storage unit;

the VT measurement module is used for detecting a current Id at a DRAIN end of the COMS tube of the target storage unit and a voltage Vt of the COMS tube of the target storage unit, and outputting the voltage Vt to the ADC conversion module when the current Id is changed;

the ADC conversion module is used for converting the voltage Vt from an analog signal to a digital signal and transmitting the digital signal to the service life calculation module.

Further, in the lifetime self-test system of the memory cell in the nonvolatile memory, the memory lifetime hash table is set before shipment of the nonvolatile memory, and is created from Vt-cycling test data of the nonvolatile memory.

The method and the system for self-detecting the service life of the storage unit in the nonvolatile storage have the following advantages that:

the method comprises the steps that after an operation instruction sent by a host is received by a control circuit, a VT self-checking instruction aiming at a target storage unit is triggered, the VT self-checking circuit obtains the current voltage Vt of the target storage unit, if the voltage Vt is smaller than a Vth threshold value, an analog signal of the voltage Vt is converted into a digital signal, a life calculation module calculates the hash value of the digital signal of the voltage Vt as an index number, a life value corresponding to the index number is searched from a preset storage life hash table, and finally the searched life value is sent to the host by the control circuit. Therefore, the present invention can automatically detect the current service life of the target storage unit before the target storage unit executes the operation instruction, and send the service life to the host, and the host judges the failure time of the target storage unit according to the service life, and further determines whether to execute the relevant operation in the target storage unit, so that the risk of data loss caused by executing the relevant operation in the storage unit to be failed can be avoided.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings used in the description will be briefly introduced, and it is obvious that the drawings in the following description are an embodiment of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts according to the drawings:

FIG. 1 is a graph of Vt-cycling test data for a non-volatile memory;

FIG. 2 is a flowchart illustrating a method for self-testing the lifetime of a memory cell in a non-volatile memory according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a system for self-checking lifetime of a memory cell in a non-volatile memory according to an embodiment of the present invention;

FIG. 4 is a block diagram of a system for self-checking the life of memory cells in a non-volatile memory in one specific example;

fig. 5 is a flowchart of a method for self-detecting the lifetime of a memory cell in a nonvolatile memory according to a specific example.

Detailed Description

The method and system for self-testing the lifetime of a memory cell in a non-volatile memory according to the present invention will be described in detail with reference to fig. 1-5 and the following embodiments. The advantages and features of the present invention will become more apparent from the following description. It is to be noted that the drawings are in a very simplified form and are all used in a non-precise scale for the purpose of facilitating and distinctly aiding in the description of the embodiments of the present invention. To make the objects, features and advantages of the present invention comprehensible, reference is made to the accompanying drawings. It should be understood that the structures, ratios, sizes, and the like shown in the drawings and described in the specification are only used for matching with the disclosure of the specification, so as to be understood and read by those skilled in the art, and are not used to limit the implementation conditions of the present invention, so that the present invention has no technical significance, and any structural modification, ratio relationship change or size adjustment should still fall within the scope of the present invention without affecting the efficacy and the achievable purpose of the present invention.

The core idea of the invention is to provide a method and a system for self-detecting the service life of a storage unit in a nonvolatile memory, so as to solve the problem that the storage unit of the nonvolatile memory in the prior art has uncertain failure time and is easy to cause data loss.

The following first introduces the principle contents related to the present invention.

The lifetime of data validity of a non-volatile memory is influenced by a combination of factors, such as erase and write times, temperature, humidity, etc. The life characteristic of the nonvolatile memory storage unit is visually represented whether the current storage unit is correctly erased or not, and the physical representation is whether the Vt characteristic of the current storage unit meets the requirement of a design threshold or not. In practical design and operation, if the Vt of a nonvolatile memory cell meets the Vth threshold requirement, the current cell is valid and can be erased normally. If the Vt characteristic does not meet the Vth threshold requirement, the current cell is erased and written to fail. As shown in fig. 1, as the erase/write frequency increases, Vt decreases until Vt < Vth, and the current cell fails. A nonvolatile memory is a specific combination of a plurality of memory cells, each of which has limited effectiveness in holding data, and the stability of the memory cells is very important to the effectiveness of data holding.

The method for judging whether the storage unit is effective is as follows:

s1, supplying voltage, which changes between-1V and 1V, of a high-voltage starting module in the nonvolatile memory to a GATE end of a COMS tube of a current storage unit, and detecting current Id of a DRAIN end;

s2, detecting DRAIN current Id and voltage Vt corresponding to the current CMOS tube when GATE end voltage (-1V) changes, and if the Id current does not change, judging that the current storage unit fails; the current Vt is less than the Vth threshold, the current cell can be determined to be failed;

s3, detecting the failure memory cell, giving the failure flag bit of the current memory cell (flag bit: 0 indicates no failure, 1 indicates failure), and reading and judging by the host whether to re-erase the current data and change the current memory cell.

By the method, the loss life of the current storage unit can be automatically alarmed, the host can actively and selectively read the data validity of each storage unit, and whether the current data is lost or not can be judged according to the service life marking signal of the storage unit.

As shown in fig. 1, a method for self-detecting a lifetime of a memory cell in a non-volatile memory according to an embodiment of the present invention includes the following steps:

in step S100, the control circuit receives an operation instruction sent by the host, triggers a VT self-test instruction for the target storage unit, and transmits the VT self-test instruction to the VT self-test circuit.

It can be understood that the host can read, write and erase the nonvolatile memory through the SPI/IIC bus, and the control circuit in the nonvolatile memory receives the operation command and analyzes the operation command to obtain the operation of the host on the target memory cell.

Because the damage of the data erasing and writing operation to the storage unit is large, the service life of the unit storage unit can be self-checked before the data erasing and writing operation is performed, so that the risk of data loss caused by the data erasing and writing operation performed on the unit storage unit which is about to fail is avoided. Therefore, preferably, when the operation instruction sent by the host includes an erase and/or write instruction, the control circuit triggers the VT self-test instruction, and the VT self-test circuit performs self-test on the service life of the unit storage unit.

In step S200, the VT self-test circuit obtains a current voltage VT of the target memory cell, and if the voltage VT is smaller than a Vth threshold, converts the voltage VT from an analog signal to a digital signal and transmits the digital signal to a life calculation module.

Specifically, the VT self-test circuit may include the following three modules: the device comprises a Pump circuit, a VT measuring module and an ADC conversion module.

The Pump circuit is a high-voltage module arranged in the nonvolatile memory chip and used as an internal-charging voltage source to output different voltages to the GATE end of the COMS tube of the target memory unit; wherein the different voltages are, for example, voltages varying between-1V and 1V.

The VT measurement module detects a current Id of a DRAIN end of the COMS tube of the target storage unit and a voltage Vt of the COMS tube of the target storage unit, and outputs the voltage Vt to the ADC conversion module when the current Id is changed; it can be understood that, when the circuit Id is unchanged, it can be determined that the voltage Vt of the cmos transistor is less than the threshold voltage Vth, that is, the target memory cell fails, and at this time, the control circuit can feed back the failed flag bit of the target memory cell to the host, and the host can determine whether to rewrite the data of the target memory cell and modify the memory cell; when the circuit Id is changed, it indicates that the target memory cell has not failed, so the current life value of the target memory cell can be further detected.

The ADC conversion module is a digital-to-analog converter, converts the voltage Vt from an analog signal to a digital signal, and transmits the digital signal to the service life calculation module.

In step S300, the lifetime calculation module calculates a hash value of the digital signal of the voltage Vt as an index number, searches a lifetime value corresponding to the index number from a preset lifetime hash table, and feeds back the lifetime value to the control circuit.

Preferably, the storage life hash table is set before the nonvolatile memory is shipped, and is created from Vt-cycling test data of the nonvolatile memory. For example, the storage lifetime hash table is an OTP (One Time Programmable) table, hash calculation is performed on each voltage Vt value in advance to obtain a corresponding index number as an OTP address, and the OTP address stores a lifetime value corresponding to the voltage Vt value in Vt-cycling test data.

Therefore, after an index number is obtained according to the current voltage Vt of the target storage unit, the life value corresponding to the index number is searched from a preset storage life hash table, and then the current life value of the target storage unit can be obtained.

And step S400, the control circuit sends the searched life value to the host.

Therefore, the control circuit sends the current life value of the target storage unit to the host, the host judges whether the target storage unit is about to fail, and if so, the target storage unit is not erased and/or written, so that the risk of data loss is avoided.

In summary, the present invention can automatically detect the current service life of the target storage unit before the target storage unit executes the operation command, and send the service life to the host, and the host determines the failure time of the target storage unit according to the service life to further determine whether to execute the related operation in the target storage unit, so as to avoid the risk of data loss caused by executing the related operation in the storage unit that is about to fail.

Based on the same inventive concept, the present invention further provides a system for self-detecting the lifetime of a memory cell in a non-volatile memory, as shown in fig. 2, comprising: a control circuit 201, a VT self-checking circuit 202 and a service life calculating module 203;

the control circuit 201 is configured to receive an operation instruction sent by a host, generate a VT self-test instruction for a target storage unit, and transmit the VT self-test instruction to the VT self-test circuit 202;

the VT self-test circuit 202 is configured to obtain a current voltage VT of the target memory cell, and if the voltage VT is smaller than a Vth threshold, convert the voltage VT from an analog signal to a digital signal and transmit the digital signal to the lifetime calculation module 203;

the lifetime calculation module 203 is configured to calculate a hash value of the digital signal of the voltage Vt as an index number, look up a lifetime value corresponding to the index number from a preset lifetime hash table, and feed back the lifetime value to the control circuit 201;

the control circuit 201 is configured to send the found life value to the host.

Preferably, when the operation command sent by the host includes an erase and/or write command, the control circuit triggers the VT self-test command.

Preferably, the VT self-test circuit includes: the device comprises a Pump circuit, a VT measuring module and an ADC conversion module;

the Pump circuit is used for outputting different voltages to the GATE end of the COMS tube of the target storage unit;

the VT measurement module is used for detecting a current Id at a DRAIN end of the COMS tube of the target storage unit and a voltage Vt of the COMS tube of the target storage unit, and outputting the voltage Vt to the ADC conversion module when the current Id is changed;

the ADC conversion module is used for converting the voltage Vt from an analog signal to a digital signal and transmitting the digital signal to the service life calculation module.

Preferably, the storage life hash table is set before the nonvolatile memory is shipped, and is created from Vt-cycling test data of the nonvolatile memory.

The following describes a method and a system for self-checking the lifetime of a memory cell in a non-volatile memory according to a specific example.

In the structure diagram shown in fig. 4, the host computer performs read, write and erase operations on the nonvolatile memory through the SPI/IIC bus (4), and the control circuit analyzes the received command to operate the storage unit;

in the invention, the control circuit analyzes the received command to carry out erasing operation on the storage unit; the direction of the data path (5) is bidirectional, and the data path represents the erasing control of the control circuit on the memory cell; the data path (1) is unidirectional, directed from the memory cell to the Vt self-test circuit; the Vt self-checking circuit automatically detects the Vt value of the memory cell currently performing the reading operation (namely, the target memory cell); the data path (2) is unidirectional and is directed from the Vt self-test circuit to the lifetime calculation block (in which the memory lifetime hash table is preset). The storage life hash table is set before each chip leaves a factory, a hash function calculation is carried out on each Vt according to the OTP table made of the Vt-cycling test data of each chip, a corresponding index number is obtained and used as an OTP address, and the time life corresponding to the Vt is stored in the OTP address. The data path (2) transmits the Vt value of the current storage unit to the service life calculation module, the service life calculation module calculates the hash value to obtain the index number and search the service life, the current service life is sent to the control circuit through the path (3), and the control circuit sends the current service life to the host.

Fig. 5 further shows a flow chart of the self-test life method, wherein the VT self-test command in the control circuit is triggered by a self-test trigger command, a trigger command sequence is designed by a chip design engineer, and the self-test of the bus input sequence is established and enters the VT self-test circuit.

The VT self-checking circuit executes the following three steps:

the Pump Circuit is enabled: a high-voltage module is arranged inside the chip, and the inside of the chip is used as an internal filling voltage source;

VT measurement: (1) a high-voltage starting module in the nonvolatile memory outputs different voltages to a GATE end of a COMS tube of the current storage unit;

(2) detecting the change of the voltage (-1V) at the GATE end, detecting the DRAIN current Id and the current corresponding voltage Vt of the COMS tube, if the current Id is not changed, judging that the current storage unit is invalid, and if the current Id is changed, outputting the current Vt to an ADC conversion module;

ADC conversion: the value of the analog Vt is output by the digital-to-analog converter as a digital signal to the lifetime calculation module.

The life calculation module executes the following three steps:

and (3) Hash calculation: and calculating the hash value of the digital signal VT as the address index number of the storage life hash table.

Hash search: the hash table of the storage life is a storage structure, the address data corresponding to the address index number is the erasing times or the life value of the factory experiment verification in advance, and the current erasing times or the life value is read according to the hash address index number.

And (3) service life output: and outputting the read current erasing times or the read life value to a bus.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. Various modifications and alterations to this invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be determined from the following claims.