Non-volatile programmable switch based on MTJ
Technical Field
The invention relates to the field of electronic switches, in particular to a non-volatile programmable switch based on MTJ.
Background
The electric control switch generally used at present mainly depends on an output pin of a controller to generate a switch control signal, so that the switching and the keeping of the switch state are realized, and the electric control switch cannot work independently of the controller. In many applications, the switch remains in the hold state for a long time, but still occupies pin resources of the controller. If the switch has the capability of keeping the working state of the switch, the occupation of resources such as controller pins and the like can be reduced, and simultaneously, the stability of the switch system can be improved because the keeping state is not influenced by the controller.
Chinese patent cn201580074129.x, published 2019, 3, 26, a programmable switching system, comprising N interconnected switching devices, a communication interface, a microprocessor and a memory. When the control software is executed on the microprocessor: the microprocessor communicates information with all the interconnected switch devices in the programmable switch system through a network through the communication interface, receives and processes the input of users on the switches of all the interconnected switch devices: when the switch is in the programming mode, the microprocessor programs and sets the interconnection switch device, and when the switch is in the switching mode, the microprocessor completes the switching function of the interconnection switch device. The connection state of the interconnection switch can be controlled through the control of the microprocessor. The system is complex, costly and has limited response speed due to the inclusion of digital processing components such as microprocessors.
Therefore, it is necessary to design a programmable switch with simple structure, low cost, fast response speed and non-volatile storage of state.
Disclosure of Invention
In view of the above-mentioned shortcomings and drawbacks of the prior art, it is an object of the present invention to provide a Magnetic Tunnel Junction (MTJ) based non-volatile programmable switch.
The invention relates to a nonvolatile programmable switch based on a magnetic tunnel junction, which comprises a read-write interface circuit, an MTJ write circuit, an MTJ unit, an MTJ read circuit, a drive circuit and a switch element, wherein the MTJ write circuit is connected with the read-write interface circuit; the read-write interface circuit is connected with the control end of the MTJ write circuit; the output end of the MTJ writing circuit is connected with the MTJ unit to realize the high-resistance and low-resistance writing of the MTJ unit; the MTJ single element is connected with the input end of the MTJ reading circuit at the same time to convert the high and low resistance states of the MTJ unit into high and low levels; the output end of the MTJ reading circuit is respectively connected with the read-write interface module and the input end of the driving circuit, and the reading and the modification of the working state of the switching element are respectively realized; the output end of the drive circuit is connected with the control end of the switch element to drive and control the working state of the switch.
Preferably, in the non-volatile programmable switch based on the Magnetic Tunnel Junction (MTJ), the control and the state information of the switch are stored by depending on the high and low resistance states of the Magnetic Tunnel Junction (MTJ). Compared with other nonvolatile programmable storage means, the MTJ adopted as the nonvolatile programmable storage unit has the advantages of high data read-write speed, almost unlimited erasing, strong radiation resistance and the like.
Preferably, the nonvolatile programmable switch based on the Magnetic Tunnel Junction (MTJ) realizes the switch information storage after power failure and the switch state recovery after power on by using the nonvolatile characteristic of the MTJ resistance state.
Preferably, the nonvolatile programmable switch based on the Magnetic Tunnel Junction (MTJ) is a programmable switch, that is, the on/off state of the switch can be modified by sending a programming instruction to the read/write interface circuit, and the like, and the corresponding modification instruction can be converted into MTJ write currents in different directions by the read/write interface circuit and the MTJ write circuit, so that the on/off state of the switch is stored in the form of MTJ high/low resistance states.
Preferably, the Magnetic Tunnel Junction (MTJ) has a multilayer film structure including a free layer and a fixed layer made of a magnetic material, and an isolation layer interposed therebetween. When the current flowing from the fixed layer to the free layer exceeds a certain critical value for a certain time, the magnetic moment direction of the free layer is parallel to the magnetic moment direction of the fixed layer, and the MTJ is in a low-resistance state; conversely, when the current flowing from the free layer to the pinned layer exceeds a threshold value for a certain time, the magnetic moment direction of the free layer is anti-parallel to the magnetic moment direction of the pinned layer, and the MTJ assumes a high resistance state.
Preferably, the switch element may be any electrically controlled switch, such as a bipolar transistor, a field effect transistor, an IGBT, a relay, an optocoupler, or the like.
Preferably, the built non-volatile programmable switch is used to use the magnetic tunnel junction as a control and information storage device of the circuit, become a part of building the circuit, and enable information and energy in the circuit to be stored in the same device.
Alternatively, in an application, the external controller may change the switch state of the switch element by sending data, address, write and enable signals to the read-write interface circuit, or may obtain the current operating state of the switch by sending address, read and enable signals to the read-write interface circuit.
Compared with the prior art, the invention has the advantages that: the invention has the advantages of non-volatility, namely the on-off state of the switch is not lost after power failure, the on-off state of the switch is automatically recovered when the system is powered on next time, high integration level, non-volatility, programmability, high read-write response speed, infinite erasing and writing, low power consumption, simple structure, low cost, high response speed and the like, can obviously reduce the resource occupation of the switch system on a controller, and can effectively improve the stability of the switch system.
Drawings
FIG. 1 is a block diagram of an embodiment of a MTJ-based non-volatile programmable switch architecture
FIG. 2 is a schematic diagram of a circuit structure of a switch control part based on MTJ according to the second embodiment
Detailed Description
In summary, in order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and of course, the described embodiments are some embodiments of the present invention, but not all embodiments. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of the embodiments of the invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, belong to the scope of the present invention.
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
The first embodiment is as follows:
a Magnetic Tunnel Junction (MTJ) -based nonvolatile programmable switch is a structural block diagram based on an MTJ nonvolatile programmable switch as shown in fig. 1, and includes a read-write interface circuit 1, an MTJ write circuit 2, an MTJ unit 3, an MTJ read circuit 4, a drive circuit 5, and a switch element 6. The read-write interface circuit 1 is connected with the control end of the MTJ write circuit 2, so that the control end of the MTJ write circuit is controlled, and control data is accurately and quickly transmitted; the output end of the MTJ writing circuit 2 is connected with the MTJ unit 3, so that the high-resistance and low-resistance writing of the MTJ unit is realized, and different circuit characteristics are reflected; the MTJ unit 3 is connected with the input end of the MTJ reading circuit 4 at the same time, and the high and low resistance states of the MTJ unit 3 are converted into high and low levels; the output end of the MTJ reading circuit 4 is connected with the input ends of the read-write interface circuit 1 and the drive circuit 5 respectively, so as to read and modify the working state of the switch element respectively; the output end of the drive circuit 5 is connected with the control end of the switch element 6 to drive and control the working state of the switch.
According to the nonvolatile programmable switch based on the Magnetic Tunnel Junction (MTJ), the control and state information of the switch are stored by depending on the high and low resistance states of the MTJ unit 3, and the state of the MTJ unit 3 is read by the MTJ reading circuit 4 and converted into the high and low levels of the electronic circuit. The state of the switch is nonvolatile, namely the on-off state of the switch is not lost after power failure, and the on-off state of the switch in the last working is automatically recovered when the system is powered on next time. The switch realizes the storage of switch information after power failure and the recovery of the switch state after power on by utilizing the nonvolatile characteristic of the MTJ resistance state. The on and off states of the switch can be modified by sending programming instructions to the read-write interface circuit 1, and the corresponding modification instructions can be converted into MTJ write currents in different directions by the read-write interface circuit 1 and the MTJ write circuit 2, so that the on and off states of the switch can be stored in the form of MTJ high and low resistance states.
Example two:
an MTJ-based non-volatile programmable switch, as shown in fig. 2, is a schematic diagram of a circuit structure of an MTJ-based switch control portion in a first embodiment, and a switch control circuit in this embodiment includes an MTJ reading circuit 7, an MTJ cell 3, a switch driving circuit 8, and a switch element 9. Wherein, the MTJ reading circuit 7 is constructed by MOS transistor, when the read enable signal is high level, the output of the reading circuit is related to the resistance values of MTJ0 and MTJ1 in MTJ cell 3: when the resistance of MTJ0 is higher than that of MTJ1, MTJ read circuit 7 outputs a low level; when the resistance of MTJ0 is lower than that of MTJ1, MTJ reading circuit 7 outputs a high level. The output level of the MTJ reading circuit 7 is converted into a drive signal of a desired voltage by a drive circuit 8 implemented by an inverter, and the drive signal is applied to a switching element 9 formed by a P-type IGBT. When the driving signal is lower than the potential of the positive electrode of the output end minus the threshold voltage of the IGBT tube, the IGBT tube is conducted, a low-resistance path is formed between the positive electrode and the negative electrode of the output end, and the on-state of the switch is realized; when the driving signal is higher than the potential of the anode of the output end minus the threshold voltage of the IGBT tube, the IGBT tube is cut off, so that a high-resistance state is presented between the anode and the cathode of the output end, and the off state of the switch is realized.
The above description is only a part of the embodiments of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.