CN113643747A

CN113643747A - Self-Error Correcting Memory Cell Based on Memristive Elements and Implicit Logic

Info

Publication number: CN113643747A
Application number: CN202110890712.5A
Authority: CN
Inventors: 王子欧; 巫超
Original assignee: Suzhou University
Current assignee: Suzhou University
Priority date: 2021-08-04
Filing date: 2021-08-04
Publication date: 2021-11-12

Abstract

The invention discloses a self-error-correcting storage unit based on a memristive element and implication logic, comprising a strobe; a first memristor for storing data during writing; and a first memristor for assisting in judging the first memristor Whether the correct second memristor is written; a certain value resistor; the source of the gate tube is electrically connected to the DL terminal through the constant value resistor, and the gate of the gate tube is electrically connected to the WL terminal, so The drain of the gate tube is electrically connected to the negative electrode of the first memristor and the negative electrode of the second memristor respectively, the positive electrode of the first memristor is electrically connected to the BL terminal, and the second memristor is electrically connected to the BL terminal. The positive pole of the device is electrically connected to the CL terminal. The invention can effectively reduce the difficulty of realizing the implied operation, improve the practical feasibility of the storage unit, and completely avoid the misoperation of other units in the array during the writing process.

Description

Self-error-correction storage unit based on memristive element and embedded logic

Technical Field

The invention relates to the field of basic circuit design of an integrated circuit memory, in particular to a self-error-correction storage unit based on a memristive element and an inclusion logic.

Background

Referring to fig. 1, a schematic diagram of a structure of an existing self-fault-tolerant memristive memory cell (a 1T2M1R memory cell, where an NMOS is used as a gate tube) based on the inclusion logic is shown, where a memristor M1 is used to store data during writing, and a memristor M2 is used to assist in determining whether the memristor M1 is correctly written. Referring to fig. 2 and fig. 3, fig. 2 is a timing diagram of a 1T2M1R cell write 1, and fig. 3 is a timing diagram of a 1T2M1R cell write 0.

The cell contains a process of implication logic, which is a boolean logic, in a complete write operation. In 8 months in 2010, an article published by the national Nature of Hewlett packard laboratory describes an implication logic implementation based on memristors, the simplest structure of the implication logic implementation is shown in figure 4, the implication logic implementation is composed of two memristors and a constant value resistor, and V is applied to positive electrodes of the two memristors respectively_condAnd V_SET(V_SETTo set "1" voltage of memristor (memristor resistance state set low), V_condLess than V_SET). The truth table of the implication logic is shown in table 1:

table 1: embodying truth tables of operation

P	Q	P→Q
			H(0)	H(0)	L(1)
H(0)	L(1)	L(1)
			L(1)	H(0)	H(0)
L(1)	L(1)	L(1)

The existing memristive memory cell structure can detect whether the memory cell itself is written with failure or not and identify which failure mode is specific while reading the memory value of the cell, but the structure has the defects that: since the cell does not require the cell to be gated during the trapping operation, when the cell is used to form a memory array, the storage values of other cells are affected during the trapping operation of a single cell, as shown in fig. 5:

generally, the WL word select signal is in the X direction, and the BL, CL and DL bit select signals are in the Y direction, if the cell in the first row and the first column is to be written, then the first row word select signal WL does not need to be turned on when the cell trapping operation in step 2 is performed, and at the same time, the level of the whole BL and CL lines in the first column will be the level satisfying the trapping operation. As can be known from the implication operation truth table 1, the operation will not affect the cell storing "1" (i.e., both the memristor M1 and the memristor M2 are in the low-resistance state), but will change the resistance state of the memristor M2 storing "0" (i.e., both the memristor M1 and the memristor M2 are in the high-resistance state), and according to the principle of fault-tolerant reading of the 1T2M1R cell, the M1 and M2 in the cell storing "0" erroneously will be in the high-resistance state (H) and the low-resistance state (L), respectively, which will affect the subsequent writing operation of the cell without implication.

In addition, the implication operation is a logic operation aiming at an ideal memristive device, and only when the memristor is in a high-resistance state R_HLow resistance state R_LAnd a custom resistance R_gThe resistance value strictly satisfies the condition R_H＞＞R_g＞＞R_LWhen necessary, the implication operation can be realized. However, such ideal conditions are difficult to achieve from the perspective of current memristor fabrication processes.

Therefore, how to optimize the cell to reduce the above-mentioned defect effect on the access is a problem to be solved by those skilled in the art for reconstructing the existing 1T2M1R memory cell structure.

Disclosure of Invention

The invention aims to provide a self-error-correction storage unit based on a memristive element and implication logic, which can effectively reduce the difficulty of implementing implication operation, improve the practical feasibility of the storage unit, and completely avoid the misoperation of other units in an array in the writing process.

The technical scheme of the invention is as follows: a self-error-correction memory cell based on memristive elements and embedded logic, the memory cell comprises

A gate pipe;

a first memristor to store data as written;

for assisting in determining whether the first memristor is writing the correct second memristor;

a resistance with a certain value;

the source electrode of the gate tube is electrically connected to the DL end through a constant value resistor, the grid electrode of the gate tube is electrically connected to the WL end, the drain electrode of the gate tube is electrically connected to the cathode of the first memristor and the cathode of the second memristor respectively, the anode of the first memristor is electrically connected to the BL end, and the anode of the second memristor is electrically connected to the CL end.

In the above technical scheme, the gate tube is an NMOS tube or a PMOS tube.

In the above technical solution, the gate pipe is configured to gate the storage unit when performing the implication operation.

In the above technical solution, the WL terminal is configured to gate enable the gate tube.

In the above technical solution, the WL terminal is configured to select an NMOS transistor as the gate transistor to be kept at a high level during writing or select a PMOS transistor as the gate transistor to be kept at a low level during writing.

The invention has the advantages that:

compared with the existing memory unit, the memory unit has the advantages that the implication operation can be realized only by a small resistance value of the constant-value resistor of the memory unit under the condition of high and low resistance values of the same memristor, the practical feasibility of the memory unit is greatly improved, and the misoperation of other units in the array in the writing process can be completely avoided.

Drawings

The invention is further described with reference to the following figures and examples:

FIG. 1 is a block diagram of a prior art 1T2M1R memory cell.

FIG. 2 is a prior art 1T2M1R memory cell write 1 timing diagram.

FIG. 3 is a timing diagram of a prior art 1T2M1R memory cell write 0 in the background art.

Fig. 4 is a schematic diagram of an implied operation structure in the background art.

FIG. 5 is a schematic diagram of a prior art 1T2M1R memory cell array with M rows and n columns.

FIG. 6 is a diagram of a memory cell 1T2M1R according to an embodiment of the present invention.

FIG. 7 is a schematic diagram of a 1T2M1R memory cell constructed M rows and n columns memory array.

Detailed Description

Example (b):

referring to fig. 6, the present invention provides a self-error-correction memory cell (taking NMOS as a gate tube for example) based on memristive elements and embedded logic, which moves a constant-value resistor electrically connected to the bottom ends of two memristors in the existing memory cell to the source of the gate tube, and uses the other end of the constant-value resistor as the input end of a DL operation level

A gate pipe NM 1;

a first memristor M1 for storing data at the time of writing;

to assist in determining whether the first memristor M1 written the correct second memristor M2;

constant value resistance R_g；

The source electrode of the gate tube NM1 is connected with a constant value resistor R_gA gate of the gate line NM1 electrically connected to the DL terminal, and drains of the gate lines NM1 electrically connected to the WL terminalThe positive electrode of the first memristor M1 is electrically connected to the BL terminal, and the positive electrode of the second memristor M2 is electrically connected to the CL terminal.

In one embodiment, the gate tube is an NMOS gate tube, and in another embodiment, it may also be a PMOS tube.

The memory cell of the invention uses the implication operation as the WL word line gating enabling, namely the WL terminal in the write operation timing diagrams 2 and 3 of the existing memory cell needs to be kept at the high level all the time, and the timing sequences of BL, CL and DL of the existing memory cell structure are still kept unchanged, thus completing one complete write operation. Furthermore, the fault-tolerant read and error detection and correction schemes of the existing memory cell structures are still applicable to the memory cell structure of the present invention. In contrast, the memory cell structure of the present invention introduces a conducting gate tube (in this example, a conducting NMOS tube) during the trapping operation, and at this time, the introduction of the conducting current and the conducting resistance of the MOS tube removes the constant value resistance R during the trapping operation_gStrictly in line with R_H＞＞R_g＞＞R_LThe limit of (2). According to experimental simulation results, compared with the existing memory cell structure, the constant-value resistor R of the memory cell is compared with the constant-value resistor R of the existing memory resistor under the condition of high and low resistance values_gThe implication operation can be achieved with only a small resistance, which also greatly improves the practical feasibility of the unit.

Referring to fig. 7, similar to the conventional memory array, the word line WL is in the X direction, and the bit lines BL, CL and DL are in the Y direction, so that if a write operation is performed on the memory cells in the first row and the first column, the word line WL0 is only gated, and the first column is gated, and the corresponding operation levels BL, CL and DL are sequentially sent to the cells to complete a write operation, thereby completely avoiding the situation of other cell malfunctions in the write process of the conventional memory cell structure.

It should be understood that the above-mentioned embodiments are only illustrative of the technical concepts and features of the present invention, and are intended to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the scope of the present invention. All modifications made according to the spirit of the main technical scheme of the invention are covered in the protection scope of the invention.

Claims

1. A self-error-correcting storage unit based on a memristive element and implication logic, wherein the storage unit comprises:

a gate tube;

a first memristor for storing data at the time of writing;

Used to assist in judging whether the first memristor is written into the correct second memristor;

A certain value of resistance;

The source of the gate is electrically connected to the DL terminal through a constant-value resistor, the gate of the gate is electrically connected to the WL terminal, and the drain of the gate is electrically connected to the first memory respectively. The negative electrode of the resistor and the negative electrode of the second memristor, the positive electrode of the first memristor is electrically connected to the BL terminal, and the positive electrode of the second memristor is electrically connected to the CL terminal.

2 . The self-error-correcting memory cell based on memristive element and implication logic according to claim 1 , wherein: the gate transistor selects an NMOS transistor or a PMOS transistor as the gate transistor. 3 .

3 . The self-error-correcting memory cell based on memristive element and implication logic according to claim 1 , wherein the gate transistor is configured to gate the memory cell when an implication operation is performed. 4 .

4 . The self-error correction memory unit based on memristive element and implication logic according to claim 3 , wherein the WL terminal is configured to enable the strobe tube. 5 .

5. The self-error correction memory cell based on memristive element and implication logic according to claim 4, characterized in that: the WL terminal is configured to select NMOS transistor as a strobe transistor to keep at a high level during writing Or choose a PMOS tube as a strobe tube and keep it at a low level when writing.