Read-write circuit of magnetic random access memory

Abstract

A read-write circuit of a magnetic random access memory (MRAM) is characterized in that each data unit comprises a switch transistor, a magnetic tunnel junction (MTJ), a word line connection, a source line connection and a bit line connection, and the read-write circuit comprises a plurality of data units, a plurality of reference units, a bit line driving circuit and a source line driving circuit, a write-in voltage offset adjusting circuit is used for sensing voltage during write-in operation, a data selection circuit switches output of the voltage, a sensitive amplifier is in charge of effectively amplifying signals in combination with sequential control, data is converted into digital signals through the SR latch. A write termination circuit is used for controlling whether the write operation is completed or not according to the data signal output by the SR latch. According to the invention, a reading function, a writing function and a writing state monitoring function are respectively realized under different direct-current working points by adopting the same set of circuit, so that the power consumption can be reduced, and the reliability can also be improved.

Description

Technical field [0001] The present invention relates to the field of magnetic random memory, and more particularly to a circuit design for operating a storage device identifying a magnetic tunnel junction state transition and its reading and writing. Background technique [0002] In recent years, magnetic random memory (MRAM) of magnetic tunnel junction (MTJ) has been considered as a future solid-state non-volatile memory, which has high-speed read and write, large capacity, and low energy. Features. Iron magnetic MTJ is usually a sandwich structure in which magnetic free layer (FL) can be changed to the magnetization direction to record different data; Tunnel Barrier Layer, TBL is located in the intermediate; magnetic properties Reference Layer, RL is located on the other side of the tunnel barrier layer, and its magnetization is constant. [0003] In order to record information in such a magnetoresistive component, a write method based on a spin momentum transfer or self-rotati...

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Problems solved by technology

[0009] But this kind of circuit also has the following problems: First, this circuit uses a reference cell when writing, but it does not clearly indicate that the reference cell configuration used when writing "P" state and writing "AP" state ("P " status is "0", "AP" status is "1")

Because, assuming that the "P" state is written, if the reference unit selects the "AP" configuration, then the reference unit configuration may be written by mistake, which is obviously not allowed

In addition, using a single reference cell, its resistance value is greatly affected by the process, so there may be a risk of misjudgment, especially in the case of high write error rate requirements

Second, this circuit uses a constant current source method during the write operation. Part of the voltage drop is consumed by the constant current source itself, and this part of the power consumption is wasted. In addition, the write operation may take a long time

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