Random number oscillator and random number generator based on magnetic tunnel junction array

Abstract

The present application provides a random number oscillator and a random number generator based on a magnetic tunnel junction array. The random number oscillator provided by the present application, by setting a read / write selection circuit and a magnetic tunnel junction array, and in each oscillation cycle, the read / write selection circuit is used to perform read / write control, so that the resistance value of the magnetic tunnel junction array is randomly distributed between a first resistance value corresponding to a parallel state and a second resistance value corresponding to an antiparallel state, forming a binomial distribution random process, and further, the magnetic tunnel junction array is used as a current-type frequency determining element or a resistance-type frequency determining element in the random number oscillator, so that the oscillation frequency of the random number oscillator can be controlled by the resistance value of the magnetic tunnel junction array, and the random change of the resistance value directly affects the oscillation frequency, so that the oscillation frequency is randomly switched with the random change of the resistance value, so that randomness is directly introduced based on the resistance change, and the generation speed of random numbers can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of random number generation, and in particular to a random number oscillator and a random number generator based on a magnetic tunnel junction array. Background Art

[0002] In the field of modern information technology, the generation of random numbers has many uses. High-quality random numbers have become a key factor in ensuring system security and reliability in many fields such as encrypted communications and security authentication.

[0003] Traditional random number oscillators usually use phase noise to generate random signals. Phase noise is a continuous random process that requires the accumulation of frequency noise to generate randomness, which limits the speed of random number generation. Summary of the invention

[0004] In view of this, the present application provides a random number oscillator and a random number generator based on a magnetic tunnel junction array to increase the speed of generating random numbers.

[0005] Specifically, the present application is implemented through the following technical solutions:

[0006] In a first aspect, the present application provides a random number oscillator based on a magnetic tunnel junction array, the random number oscillator comprising a read / write selection circuit and a magnetic tunnel junction array; the magnetic tunnel junction array comprising a plurality of magnetic tunnel junctions, the magnetic tunnel junctions comprising a parallel state and an antiparallel state, the magnetic tunnel junctions having a first resistance value in the parallel state; the magnetic tunnel junctions having a second resistance value in the antiparallel state; the first resistance value and the second resistance value are different; wherein,

[0007] The read / write selection circuit is used to select a first magnetic tunnel junction in the magnetic tunnel junction array to enter a read operation in each oscillation cycle, and select a second magnetic tunnel junction in the magnetic tunnel junction array other than the first magnetic tunnel junction to enter a write operation when a preset write rule is satisfied, so that the resistance value of the magnetic tunnel junction array is randomly distributed between a first resistance value corresponding to the parallel state and a second resistance value corresponding to the anti-parallel state;

[0008] The magnetic tunnel junction array is used as a current-type frequency determining element or a resistance-type frequency determining element in the random number oscillator, so that the oscillation frequency of the random number oscillator is controlled by the resistance value of the magnetic tunnel junction array, and the oscillation frequency of the oscillation signal generated by the random number oscillator is randomly switched between a first oscillation frequency corresponding to the first resistance value and a second oscillation frequency corresponding to the second resistance value through the random distribution of the resistance value between the first resistance value and the second resistance value.

[0009] A second aspect of the present application provides a random number generator, which includes any of the random number oscillators described above.

[0010] The random number oscillator and random number generator based on the magnetic tunnel junction array provided by the present application, by setting a read-write selection circuit and a magnetic tunnel junction array, and in each oscillation cycle, the read-write selection circuit is used to perform read-write control, so that the resistance value of the magnetic tunnel junction array is randomly distributed between the first resistance value corresponding to the parallel state and the second resistance value corresponding to the anti-parallel state, forming a binomial distribution random process. Furthermore, the magnetic tunnel junction array is used as a current-type frequency determining element or a resistance-type frequency determining element in the random number oscillator, so that the oscillation frequency of the random number oscillator can be controlled by the resistance value of the magnetic tunnel junction array, and the random change of the resistance value directly affects the oscillation frequency, so that the oscillation frequency is randomly switched with the random change of the resistance value. In this way, in the first aspect, compared with Traditional methods do not rely on the accumulation of phase noise to generate randomness, but directly introduce randomness based on resistance changes. Since the parallel and anti-parallel states of the magnetic tunnel junction array are switched through spin transfer torque technology (VCMA), this switching is completed within nanoseconds. This not only increases the speed of random number generation, but also supports higher oscillation frequencies. Secondly, since the energy consumption of the magnetic tunnel junction is extremely low, while maintaining high-speed operation, the overall power consumption of the random number oscillator can be greatly reduced. Thirdly, the magnetic tunnel junction can withstand a large number of flips, which can improve the durability of the random number oscillator. High durability can not only increase its lifespan, but also improve its adaptability. Fourthly, the magnetic tunnel junction array can also actively amplify thermal noise through an external voltage to improve the effect of random number generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A schematic diagram of a first embodiment of a random number oscillator based on a magnetic tunnel junction array provided in the present application;

[0012] Figure 2 A schematic diagram of an oscillation signal shown in an exemplary embodiment of the present application;

[0013] Figure 3 A schematic diagram of a second embodiment of a random number oscillator based on a magnetic tunnel junction array provided in the present application;

[0014] Figure 4 A schematic diagram of a third embodiment of a random number oscillator based on a magnetic tunnel junction array provided in the present application;

[0015] Figure 5 A schematic diagram of a relaxation oscillator exemplarily shown in the present application;

[0016] Figure 6A schematic diagram of a Wien bridge oscillator exemplarily shown in the present application;

[0017] Figure 7 A schematic diagram of a phase shift oscillator shown as an exemplary embodiment of the present application;

[0018] Figure 8 A schematic diagram of a phase shift oscillator shown as another exemplary embodiment of the present application;

[0019] Fig. 9 A schematic diagram of a harmonic oscillator based on tail current control exemplarily shown in the present application;

[0020] Fig.10 A schematic diagram of a ring oscillator shown as an exemplary embodiment of the present application;

[0021] Fig.11 for Fig.10 A partial schematic diagram of the B element in the ring oscillator shown. DETAILED DESCRIPTION

[0022] Here, exemplary embodiments will be described in detail, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application.

[0023] The terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used in this article refers to and includes any or all possible combinations of one or more associated listed items.

[0024] It should be understood that although the terms first, second, third, etc. may be used in the present application to describe various information, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0025] Specific embodiments are given below to introduce the technical solution of the present application in detail.

[0026] Figure 1 This is a schematic diagram of a first embodiment of a random number oscillator based on a magnetic tunnel junction array provided in this application. Figure 1The random number oscillator provided in this embodiment includes a read / write selection circuit and a magnetic tunnel junction array; the magnetic tunnel junction array includes a plurality of magnetic tunnel junctions, the magnetic tunnel junctions include a parallel state and an anti-parallel state, the magnetic tunnel junctions have a first resistance value in the parallel state; the magnetic tunnel junctions have a second resistance value in the anti-parallel state; the first resistance value and the second resistance value are different; wherein,

[0027] The read / write selection circuit is used to select a first magnetic tunnel junction in the magnetic tunnel junction array to enter a read operation in each oscillation cycle, and select a second magnetic tunnel junction in the magnetic tunnel junction array other than the first magnetic tunnel junction to enter a write operation when a preset write rule is satisfied in a current oscillation cycle, so that the resistance value of the magnetic tunnel junction array is randomly distributed between a first resistance value corresponding to the parallel state and a second resistance value corresponding to the antiparallel state;

[0028] The magnetic tunnel junction array is used as a current-type frequency determining element or a resistance-type frequency determining element in the random number oscillator, so that the oscillation frequency of the random number oscillator is controlled by the resistance value of the magnetic tunnel junction array, and the oscillation frequency of the oscillation signal generated by the random number oscillator is randomly switched between a first oscillation frequency corresponding to the first resistance value and a second oscillation frequency corresponding to the second resistance value through the random distribution of the resistance value between the first resistance value and the second resistance value.

[0029] For details, please refer to Figure 1 The number of magnetic tunnel junctions included in the magnetic tunnel junction array is set according to actual needs and is not limited in this embodiment. For example, in one embodiment, the magnetic tunnel junction array includes 2 magnetic tunnel junctions; for another example, in another embodiment, the magnetic tunnel junction array includes 3 magnetic tunnel junctions.

[0030] It should be noted that each magnetic tunnel junction in the magnetic tunnel junction array is a voltage-controlled magnetic tunnel junction. It is understandable that each magnetic tunnel junction includes a parallel state and an antiparallel state. Specifically, the magnetic tunnel junction has two layers of ferromagnetic materials, and the parallel state and the antiparallel state specifically refer to the relative relationship between the magnetization directions of the upper and lower layers of ferromagnetic materials, wherein the parallel state refers to the upper and lower layers of ferromagnetic materials having the same magnetization direction and parallel magnetization directions. At this time, the magnetic tunnel junction has a first resistance value. Further, in the parallel state, since the upper and lower layers of ferromagnetic materials have the same magnetization direction, the spin direction of the electron is easier to pass through the tunnel barrier, and the first resistance value is low; similarly, the antiparallel state refers to the upper and lower layers of ferromagnetic materials having opposite magnetization directions and antiparallel magnetization directions. At this time, the magnetic tunnel junction has a second resistance value. Further, in the antiparallel state, the magnetization directions of the ferromagnetic materials on the upper and lower sides are opposite, the spin direction of the electron is blocked, and it is more difficult to pass through the tunnel barrier, and the second resistance value is relatively high.

[0031] The random number oscillator provided in this embodiment can avoid the problems of failure to flip, jamming, and short circuit caused by process drift and yield when a single magnetic tunnel junction is used by setting a magnetic tunnel junction array, thereby improving reliability and durability.

[0032] For further information, please refer to Figure 1 The random number oscillator provided in this embodiment also includes a read-write selection circuit, which is used to select a magnetic tunnel junction in the magnetic tunnel junction array in the random number oscillator as the first magnetic tunnel junction to enter a read operation in each oscillation cycle of the random number oscillator, and when the current oscillation cycle meets the preset write rule, select another magnetic tunnel junction in the magnetic tunnel junction array except the first magnetic tunnel junction as the second magnetic tunnel junction to enter a write operation, so that the resistance value of the magnetic tunnel junction array is randomly distributed between the first resistance value corresponding to the parallel state and the second resistance value corresponding to the anti-parallel state.

[0033] It should be noted that when selecting the first magnetic tunnel junction and the second magnetic tunnel junction, they can be selected randomly, or other random number oscillators or counters can generate control signals, and then the selection is made based on the control signals.

[0034] Specifically, in each oscillation cycle, a magnetic tunnel junction must be selected for a read operation. Furthermore, it is not necessary to have a magnetic tunnel junction for a write operation in each oscillation cycle. Only when the current oscillation cycle satisfies the preset write rule, a magnetic tunnel junction performs a write operation. Among them, the preset write rule is set according to actual needs, and is not limited in this embodiment. For example, in one possible implementation, the preset write rule may be to perform a write operation every N oscillation cycles, that is, in the first N oscillation cycles, only a read operation is performed, and in the N+1th cycle, in addition to a magnetic tunnel junction for a read operation, there is another magnetic tunnel junction for a write operation.

[0035] It should be noted that the read operation is used to detect the resistance state of the magnetic tunnel junction, that is, to determine whether it is at the first resistance value or the second resistance value. The write operation is intended to flip the magnetization direction of the second magnetic tunnel junction by applying current to switch it between the parallel state and the antiparallel state.

[0036] Specifically, by selecting a magnetic tunnel junction for a read operation in each oscillation cycle, and selecting other magnetic tunnel junctions for a write operation according to a preset write rule, the magnetization state of the magnetic tunnel junctions in the magnetic tunnel junction array can be effectively controlled. This read-write selection mechanism allows the resistance value of the magnetic tunnel junction array (it should be noted that the resistance value of the magnetic tunnel junction array refers to the resistance value of the magnetic tunnel junction currently entering the read operation) to be randomly distributed between the first resistance value and the second resistance value, thereby introducing randomness.

[0037] Furthermore, in this embodiment, the magnetic tunnel junction array replaces the current-type frequency determining element or the resistance-type frequency determining element in the random number oscillator, so that randomness can be embedded in the oscillation frequency, so that the oscillation frequency changes with the random flipping of the magnetic tunnel junction, even if the oscillation frequency of the random number oscillator is controlled by the resistance value of the magnetic tunnel junction array.

[0038] Figure 2 This is a schematic diagram of an oscillation signal according to an exemplary embodiment of the present application. Figure 2 R MTJ Refers to the resistance value of the magnetic tunnel junction array, V OUT Refers to the oscillation signal. Figure 2 The oscillation frequency of the random number oscillator is controlled by the resistance value of the magnetic tunnel junction array. Referring to the previous description, the resistance value of the magnetic tunnel junction array is randomly distributed between a first resistance value and a second resistance value. In this way, the oscillation frequency of the oscillation signal generated by the random number oscillator randomly switches between a first oscillation frequency corresponding to the first resistance value and a second oscillation frequency corresponding to the second resistance value.

[0039] For details, see Figure 2It can be understood that the resistance value of the magnetic tunnel junction array is the first resistance value When The periodic oscillation of the magnetic tunnel junction array is a second resistance value. When (where ), the random number oscillator will be The periodic oscillation of K and , is a fixed constant.

[0040] It should be noted that when the resistance value of the magnetic tunnel junction array changes with environmental random noise such as temperature change and magnetic field change, the oscillation frequency will also change accordingly.

[0041] It should be noted that by selecting a second magnetic tunnel junction other than the first magnetic tunnel junction in the magnetic tunnel junction array to enter a write operation, the state switching of the magnetic tunnel junction can be accelerated, and the generation of random numbers can be accelerated.

[0042] The random number oscillator based on the magnetic tunnel junction array provided in the present embodiment, by setting a read / write selection circuit and a magnetic tunnel junction array, and in each oscillation cycle, the read / write selection circuit is used to perform read / write control, so that the resistance value of the magnetic tunnel junction array is randomly distributed between the first resistance value corresponding to the parallel state and the second resistance value corresponding to the anti-parallel state, forming a binomial distribution random process. Furthermore, the magnetic tunnel junction array is used as a current-type frequency determining element or a resistance-type frequency determining element in the random number oscillator, so that the oscillation frequency of the random number oscillator can be controlled by the resistance value of the magnetic tunnel junction array, and the random change of the resistance value directly affects the oscillation frequency, so that the oscillation frequency is randomly switched with the random change of the resistance value. In this way, in the first aspect, compared with Traditional methods do not rely on the accumulation of phase noise to generate randomness, but directly introduce randomness based on resistance changes. Since the parallel and anti-parallel states of the magnetic tunnel junction array are switched through spin-transfer torque technology, this switching is completed within nanoseconds. This not only increases the speed of random number generation, but also supports higher oscillation frequencies. Secondly, since the energy consumption of the magnetic tunnel junction is extremely low, while maintaining high-speed operation, the overall power consumption of the random number oscillator can be greatly reduced. Thirdly, the magnetic tunnel junction can withstand a large number of flips, which can improve the durability of the random number oscillator. High durability can not only increase its lifespan, but also improve its adaptability. Fourthly, the magnetic tunnel junction array can also actively amplify thermal noise through an external voltage to improve the effect of random number generation.

[0043] Figure 3 For a schematic diagram of a second embodiment of a random number oscillator based on a magnetic tunnel junction array provided in this application, please refer to Figure 3Based on the above embodiment, the random number oscillator provided in this embodiment, the read / write selection circuit includes a voltage source circuit, a plurality of selection circuits, and a control circuit for providing control signals to the plurality of selection circuits; the number of the plurality of selection circuits is the same as the number of magnetic tunnel junctions included in the magnetic tunnel junction array, and each selection circuit is electrically connected to a magnetic tunnel junction; wherein,

[0044] The voltage source circuit is used to provide a positive read voltage and a negative write voltage for each selection circuit;

[0045] Each selection circuit is used to control the state of the magnetic tunnel junction connected to the selection circuit based on the control signal; wherein the state includes an isolation state, a read state and a write state;

[0046] The control circuit is used to provide control signals to all selection circuits so as to select a first magnetic tunnel junction in the magnetic tunnel junction array to enter a read operation in each oscillation cycle, and to select a second magnetic tunnel junction in the magnetic tunnel junction array other than the first magnetic tunnel junction to enter a write operation when the current oscillation cycle satisfies a preset write rule.

[0047] Specifically, referring to the above description, it can be understood that the read / write selection circuit plays a key role in controlling the magnetic tunnel junction array. It should be noted that the read / write selection circuit includes a series of sub-circuits, each of which performs a specific function and together realizes the control of the magnetic tunnel junction array.

[0048] For further information, see Figure 3 ,exist Figure 3 In the example shown, the read / write selection circuit includes a voltage source circuit, multiple selection circuits (the number of selection circuits is the same as the number of magnetic tunnel junctions included in the magnetic tunnel junction array, and one selection circuit is electrically connected to one magnetic tunnel junction for controlling the state of the magnetic tunnel junction) and a control circuit.

[0049] The voltage source circuit can provide a positive read voltage and a negative write voltage for the selection circuit. The positive read voltage provided by the voltage source circuit serves as a power source for the random number oscillator, providing energy for the oscillation process of the random number oscillator, ensuring that the entire random number oscillator can oscillate at a certain frequency.

[0050] It should be noted that the magnitude of the forward read voltage will have a direct impact on the oscillation frequency of the random number oscillator. A larger voltage will produce a larger current intensity, shorten the oscillation period of the random number oscillator, and increase the oscillation frequency; a smaller voltage will produce a smaller current intensity, increase the oscillation period of the random number oscillator, and reduce the oscillation frequency. The magnitude of the forward read voltage is set according to actual needs and is not limited in this embodiment.

[0051] Furthermore, the voltage source circuit can also provide a negative write voltage for the selection circuit, wherein the negative write voltage is responsible for controlling the magnetic tunnel junction to perform a write operation, in the expectation that the magnetic tunnel junction can flip under the write operation, that is, accelerate the flipping process of the magnetic tunnel junction, accelerate the binomial distribution process of the resistance value, and accelerate the generation of random numbers (that is, in a certain oscillation cycle, a negative write voltage is applied to a certain magnetic tunnel junction, so that the magnetic tunnel junction performs a write operation. Under the write operation, the magnetic tunnel junction may flip, so that, subsequently, the magnetic tunnel junction will further enter the read operation, so that the resistance value can be quickly and randomly switched between the first resistance value and the second resistance value, which can accelerate the generation of random numbers).

[0052] As described above, the magnetic tunnel junction has two states, a parallel state and an antiparallel state, which represent two magnetization states of the magnetic tunnel junction. When the current oscillation cycle satisfies the preset write rule and the second magnetic tunnel junction to be written is selected, the energy barrier between the two magnetization states can be overcome by applying a negative input voltage to the second magnetic tunnel junction, thereby promoting the flipping of the second magnetic tunnel junction. In this way, by introducing a negative write voltage, the resistance value of the magnetic tunnel junction array can be quickly switched between the first resistance value in the parallel state and the second resistance value in the antiparallel state, thereby accelerating the generation of random numbers.

[0053] It should be noted that the magnitude of the negative write voltage can accurately control the switching of the magnetization state. In actual operation, the magnitude of the negative write voltage is also set according to actual needs, and is not limited in this embodiment.

[0054] Furthermore, each selection circuit can control the state of the magnetic tunnel junction connected to the selection circuit according to the received control signal, that is, control the magnetic tunnel junction to switch between the isolation state, the read state and the write state. The isolation state refers to the magnetic tunnel junction not being connected to the circuit, the read state refers to the magnetic tunnel junction being connected to the circuit, and a positive read voltage is applied to both ends thereof, and it enters the read operation; the write state refers to the magnetic tunnel junction being connected to the circuit, and a negative write operation is applied to both ends thereof, and it enters the write operation.

[0055] It should be noted that when the magnetic tunnel junction is in a read state, the magnetic tunnel junction establishes a connection with the read operation circuit, so that the read operation circuit can determine whether the magnetic tunnel junction is currently in the first resistance value or the second resistance value; further, when the magnetic tunnel junction is in a write state, the write operation circuit will perform a write operation on the magnetic tunnel junction in order to quickly change the magnetization state of the magnetic tunnel junction, that is, quickly change the resistance value of the magnetic tunnel junction to accelerate the generation of random numbers.

[0056] Furthermore, in one oscillation cycle, after a certain magnetic tunnel junction is placed in a read state by the selection circuit, the resistance value of the magnetic tunnel junction can be read, and then an oscillation signal can be generated according to the resistance value. Furthermore, it can be determined according to a preset write rule whether to switch the state of a certain magnetic tunnel junction array to a write state in the current oscillation cycle, and for other magnetic tunnel junctions, they are placed in an isolation state. In this way, during the operation of the random number oscillator, the selection circuit switches the magnetic tunnel junction to a different state at a required time point according to the control signal, so as to realize an orderly read and write operation on the magnetic tunnel junction array, and then an oscillation signal is generated based on the read resistance value.

[0057] It should be noted that the specific control strategy of the control circuit is set according to actual needs and is not limited in this embodiment.

[0058] Optionally, in a possible implementation, the control circuit is specifically used to sequentially control each magnetic tunnel junction in the magnetic tunnel junction array to enter a read state, and in a current oscillation cycle, control the next magnetic tunnel junction of the magnetic tunnel junction currently entering the read state to enter a write state.

[0059] In this embodiment, in one oscillation cycle, one magnetic tunnel junction is in a read state, and another magnetic tunnel junction is in a write state, and the magnetic tunnel junction that enters the write state is the next magnetic tunnel junction of the magnetic tunnel junction that currently enters the read state. In each oscillation cycle, each magnetic tunnel junction is sequentially controlled to enter the read state, so that in one oscillation cycle, a magnetic tunnel junction in a write state may flip, resulting in a change in resistance value, and in the next oscillation cycle, the magnetic tunnel junction immediately enters the read state to affect the oscillator through its resistance value, so that the generation of random numbers can be further accelerated.

[0060] Optionally, in a possible implementation, Figure 4 This is a schematic diagram of the third embodiment of the random number oscillator based on the magnetic tunnel junction array provided by the present application. Figure 4 In a possible implementation, the voltage source circuit includes a first voltage source for providing a positive read voltage and a second voltage source for providing a negative write voltage; each selection circuit includes a first selection circuit connected to the first voltage source, and a second selection circuit connected to the second voltage source;

[0061] The control circuit ( Figure 4), which is used to provide control signals to the first selection circuit and the second selection circuit to control the state of the magnetic tunnel junction connected to the first selection circuit and the second selection circuit; wherein, when the magnetic tunnel junction is connected to the circuit through the first selection circuit, the first voltage source provides a forward read voltage to the magnetic tunnel junction to put the magnetic tunnel junction into a read state, and when the magnetic tunnel junction is connected to the circuit through the second selection circuit, the second voltage source provides a reverse write voltage to the magnetic tunnel junction to put the magnetic tunnel junction into a write state.

[0062] Please continue to refer to Figure 4 ,exist Figure 4 In the example shown, the first selection circuit includes a first analog switch K1 and a second analog switch K2; wherein,

[0063] The control end of the first analog switch K1 and the control end of the second analog switch K2 are connected to form the control end of the first selection circuit, which is used to receive a control signal from the control circuit;

[0064] A first end of the first analog switch K1 is connected to the positive end of the first voltage source, and a second end of the first analog switch is connected to the positive end of the magnetic tunnel junction;

[0065] The first end of the second analog switch K2 is connected to the negative end of the magnetic tunnel junction, and the second end of the second analog switch K2 is connected to the negative end of the first voltage source ( Figure 4 GND1 in the figure represents the negative terminal of the first voltage source) connection;

[0066] The second selection circuit includes a third analog switch K3 and a fourth analog switch K4; wherein,

[0067] The control ends of the third analog switch K3 and the fourth analog switch K4 are connected to form the control end of the second selection circuit, which is used to receive a control signal from the control circuit;

[0068] A first end of the third analog switch K3 is connected to the positive end of the second voltage source, and a second end of the third analog switch K3 is connected to the negative end of the magnetic tunnel junction;

[0069] The first end of the fourth analog switch K4 is connected to the positive end of the magnetic tunnel junction, and the second end of the fourth analog switch K4 is connected to the negative end of the second voltage source ( Figure 4 GND2 in the figure represents the negative terminal of the second voltage source).

[0070] Combination Figure 4 , the following is a brief introduction to the working principle of the read-write selection circuit:

[0071] It should be noted that, refer to Figure 4When the control circuit decides to perform a read operation on a certain magnetic tunnel junction, the control circuit sends a control signal to the first selection circuit connected to the magnetic tunnel junction, and then after the first analog switch and the second analog switch in the first selection circuit receive the control signal, the first analog switch and the second analog switch are both closed, so that the first voltage source is electrically connected to the magnetic tunnel junction, so that the positive read voltage of the first voltage source can act on the magnetic tunnel junction, and the magnetic tunnel junction can be read; further, when the control circuit decides to perform a write operation on a certain magnetic tunnel junction, the control circuit sends a control signal to the second selection circuit connected to the magnetic tunnel junction, and under the control of the control signal, the third analog switch and the fourth analog switch are both closed, so that the second voltage source is electrically connected to the magnetic tunnel junction, so that the negative write voltage provided by the second voltage source can act on the magnetic tunnel junction, and the magnetic tunnel junction can be written.

[0072] Please refer to Figure 4 For the convenience of explanation, the magnetic tunnel junctions in the magnetic tunnel junction array are sequentially recorded as MTJi; wherein i ranges from 0 to n (the value of n is set according to actual needs); further, the control signal of the first selection circuit connected to MTJi is recorded as RSEL, and the control signal of the second selection circuit connected to MTJi is recorded as WSEL.

[0073] Combined with the above description, for example, in one embodiment, MTJ0 is controlled to enter the read operation, MTJ1 is controlled to perform the write operation, and other magnetic tunnel junctions enter the isolation state. At this time, RSEL<0>=1, WSEL<0>=0; RSEL<1>=0, WSEL<1>=1; RSEL<j>=0, WSEL<j>=0, where j is 2 to n. In this way, MTJ0 can be made to enter the read operation so that its state (resistance value) affects the oscillator, and MTJ1 can be made to enter the write operation so that it can flip for use by the oscillator.

[0074] The random number oscillator provided in this embodiment, firstly, realizes the random distribution of resistance value by randomly switching between the parallel state and the antiparallel state of the magnetic tunnel junction. Furthermore, the random distribution of resistance value directly affects the oscillation frequency of the oscillator, making it randomly switch between the oscillation frequencies corresponding to different resistance values, thereby realizing the generation of random oscillation signals. Compared with the traditional random number generation scheme, this scheme can generate high-quality random numbers more naturally, and does not need to rely on the accumulation of frequency noise to generate randomness; secondly, the magnetic tunnel junction has different resistance values ​​in the parallel state and the antiparallel state, and the resistance values ​​in the two states correspond to different oscillation frequencies. In this way, the oscillation frequency can randomly jump between two different frequencies, so as to effectively control the operating frequency of the random number oscillator, so that the random number oscillator has good controllability.

[0075] Optionally, in a possible implementation, the random number oscillator may be a relaxation oscillator, a Wien bridge oscillator, a phase-shift oscillator, or a harmonic oscillator based on tail current control.

[0076] It should be noted that the specific circuit structures of the relaxation oscillator, the Wien bridge oscillator, the phase-shift oscillator, and the harmonic oscillator based on tail current control are set according to actual needs and are not limited in this embodiment.

[0077] Here are a few examples to introduce each type of random number oscillator:

[0078] (1) Relaxation oscillator;

[0079] Figure 5 This is a schematic diagram of a relaxation oscillator exemplarily shown in this application. Figure 5 , wherein the random number oscillator based on the magnetic tunnel junction array provided in the present application may be a relaxation oscillator. On the basis of the above embodiment, the relaxation oscillator further includes a current mirror circuit, a charge and discharge circuit, a comparator and a T trigger; wherein,

[0080] The current mirror circuit is used to mirror the current formed by the read / write selection circuit and the magnetic tunnel junction array to the charge / discharge circuit, so as to charge the charge / discharge circuit with the current;

[0081] The charging and discharging circuit is used to charge the capacitor in the charging and discharging circuit through the charging path in the charging state, and discharge the capacitor through the discharging path in the discharging state;

[0082] The comparator is used to compare the capacitor voltage of the capacitor with a reference voltage and generate a comparison result;

[0083] The T trigger is used to generate a state control signal for controlling the charge and discharge state of the charge and discharge circuit according to the comparison result, so as to control the charging path to be turned on when the capacitor voltage is less than the reference voltage so that the charge and discharge circuit enters the charging state, and to control the discharge path to be turned on when the capacitor voltage exceeds the reference voltage so that the charge and discharge circuit enters the discharge state.

[0084] Specifically, the current mirror circuit can accurately transmit the current changes in the magnetic tunnel junction array to the charging and discharging circuit, providing a stable charging current source for the charging and discharging circuit; the charging and discharging circuit contains a capacitor element, and in the charging state, the current charges the capacitor through the charging path, and the voltage of the capacitor gradually increases with the accumulation of time. In the discharging state, the current discharges the capacitor through the discharge path, and the voltage of the capacitor gradually decreases.

[0085] Furthermore, the comparator is composed of an operational amplifier, which is used to compare the voltage of the capacitor (for the convenience of distinction, the voltage of the capacitor is recorded as the capacitor voltage) with a preset reference voltage to obtain a comparison result, and use the comparison result as a basis for controlling the state switching of the charge and discharge circuit. In this way, the T trigger can generate a state control signal for controlling the charge and discharge state of the charge and discharge circuit according to the comparison result generated by the comparator. Specifically, when the capacitor voltage is less than the reference voltage, a specific signal is output to control the charging path of the charge and discharge circuit to be turned on, indicating that the charge and discharge circuit enters the charging state, and when the capacitor voltage exceeds the reference voltage, another signal is output to control the discharge path of the charge and discharge circuit to be turned on, indicating that the charge and discharge circuit enters the discharge state.

[0086] Optional, please continue to refer to Figure 5 In a possible implementation, when the random number oscillator is a relaxation oscillator, the control circuit includes a counter and a decoder; wherein,

[0087] The counter is used to record the triggering event in the state control signal and output the accumulated counting result;

[0088] The decoder is used to convert the accumulated counting result into a control signal of a selection circuit connected to each magnetic tunnel junction in the magnetic tunnel junction array.

[0089] Specifically, the counter is used to record the number of trigger events. When the T flip-flop switches between charge and discharge, the counter records each trigger event and accumulates the number of triggers. Further, the counter transmits the accumulated count result to the decoder, which converts the accumulated count result into a control signal for the selection circuit of each magnetic tunnel junction in the magnetic tunnel junction array to control the required magnetic tunnel junction to perform a read operation or a write operation in each oscillation cycle.

[0090] This embodiment provides a specific random number oscillator, which can generate an oscillation signal and high-quality random numbers by cooperating with a relaxation oscillator through the random characteristics of a magnetic tunnel junction array; in addition, by combining a current mirror circuit with a charge and discharge circuit, in conjunction with a counter and a decoder, the read and write operations of the magnetic tunnel junction can be accurately controlled to ensure that the randomness generation process is efficient and reliable; further, by controlling different selection circuits through a counter and a decoder, different magnetic tunnel junctions can be flexibly selected for operation.

[0091] (2) Wien bridge oscillator

[0092] Figure 6 This is a schematic diagram of a Wien bridge oscillator exemplarily shown in this application. Figure 6, wherein the random number oscillator based on the magnetic tunnel junction array provided in the present application may be a Wien bridge oscillator. For further information, please refer to Figure 4 For the convenience of explanation, Figure 4 In the example, all parts except the first voltage source are uniformly denoted as M. Figure 6 When the random number oscillator is a Wien bridge oscillator, the random number oscillator is as follows: Figure 4 The random number oscillator shown in FIG. 1 includes a first voltage source and M, and when the random number oscillator is a Wien bridge oscillator, the specific composition of the first voltage source is as follows: Figure 6 As shown, the specific working principle of the Wien bridge oscillator is described in the related art, which will not be repeated here. In this embodiment, the resistor in the traditional Wien bridge oscillator is replaced with a magnetic tunnel junction array, which can accelerate the generation of random numbers.

[0093] (3) Phase-shift oscillator;

[0094] Figure 7 This is a schematic diagram of a phase shift oscillator provided as an example in the present application. Figure 8 This is a schematic diagram of a phase shift oscillator shown in another exemplary embodiment of the present application. Figure 7 and Figure 8 , wherein the random number oscillator based on the magnetic tunnel junction array provided in the present application may be a phase shift oscillator, and the phase shift oscillator is as follows Figure 4 The random number oscillator shown in FIG. 1 includes a first voltage source and M, and when the random number oscillator is a phase shift oscillator, the specific composition of the first voltage source is as follows: Figure 7 As shown, the specific working principle of the phase shift oscillator is described in the related art, which will not be repeated here. In this embodiment, at least one resistor in the traditional phase shift bridge oscillator is replaced with a magnetic tunnel junction array, which can accelerate the generation of random numbers.

[0095] (4) Harmonic oscillator based on tail current control;

[0096] Fig. 9 For a schematic diagram of a harmonic oscillator based on tail current control shown in this application, please refer to Fig. 9 , wherein the random number oscillator based on the magnetic tunnel junction array provided in the present application can be a harmonic oscillator based on tail current control, and the harmonic oscillator based on tail current control is as follows Figure 4 The random number oscillator shown in FIG. 1 includes a first voltage source and M, and when the random number oscillator is a harmonic oscillator based on current control, the specific composition of the first voltage source is as follows: Fig. 9As shown, the specific working principle of the oscillator is described in the relevant technology and will not be repeated here. In this embodiment, the tail current in the traditional harmonic oscillator based on tail current control is replaced by a magnetic tunnel junction array, which can accelerate the generation of random numbers.

[0097] The random number oscillator provided in the present application replaces the resistance or tail current of the Wien bridge oscillator, phase shift oscillator, relaxation oscillator, and harmonic oscillator based on tail current control with a magnetic tunnel junction array, and can embed randomness into the oscillation frequency so that the oscillation frequency itself also changes with the random flipping of the magnetic tunnel junction.

[0098] It should be noted that the random number oscillator provided in the present application may also be a current type sawtooth wave oscillator, a twin-T oscillator, a gate circuit oscillator, or other sinusoidal wave or harmonic oscillator.

[0099] It should be noted that the random number oscillator provided in the present application may also be a ring oscillator. The ring oscillator is introduced below:

[0100] Fig.10 is a schematic diagram of a ring oscillator shown in an exemplary embodiment of the present application, Fig.11 for Fig.10 A partial schematic diagram of the B element in the ring oscillator shown in FIG. Fig.10 and Fig.11 The random number oscillator provided in this embodiment is a ring oscillator. In this case, the voltage source circuit includes a ring circuit composed of an odd number of NOT gates; the output end of each NOT gate is used to provide a positive read voltage or a negative write voltage to a magnetic tunnel junction array; the selection circuit includes a third selection circuit connected to the NOT gate; wherein,

[0101] The third selection circuit includes a fifth analog switch and a sixth analog switch; wherein,

[0102] The control ends of the fifth analog switch and the sixth analog switch are connected to form the control end of the third selection circuit, which is used to receive the control signal from the control circuit;

[0103] The first end of the fifth analog switch constitutes the input end of the selection circuit, and the second end of the fifth analog switch is connected to the positive end of the magnetic tunnel junction;

[0104] A first end of the sixth analog switch is connected to the negative end of the magnetic tunnel junction, and a second end of the sixth analog switch constitutes an output end of the selection circuit.

[0105] It should be noted that the number of NOT gates in the ring circuit is an odd number. Due to the inverting effect of the NOT gate, a certain phase delay will be generated each time the signal passes through the NOT gate. When the signal passes through an odd number of NOT gates, an oscillation signal can be formed.

[0106] Furthermore, the output of each NOT gate will generate a positive read voltage or a negative write voltage, which directly acts on the magnetic tunnel junction in the magnetic tunnel junction array to change its state. This alternating positive and negative voltage acts on the magnetic tunnel junction to switch its state between write operation or read operation, thereby generating randomness.

[0107] The third selection circuit is used to control the transmission of voltage to ensure that a correct voltage acts on a certain magnetic tunnel junction in the magnetic tunnel junction array.

[0108] The random number oscillator provided in this embodiment is a ring oscillator, which generates high-quality random numbers by controlling the random switching of magnetic tunnel junctions through a combination of a NOT gate, an analog switch, and a magnetic tunnel junction array using an alternating voltage source. In addition, a selection circuit is used to ensure that each MTJ can correctly receive the control signal and voltage to achieve accurate random number output.

[0109] To sum up, it can be understood that the use of a magnetic tunnel junction array to replace the tail current, bias current, and resistance in a random number oscillator can accelerate the generation of random numbers. In addition, by flipping the magnetic tunnel junction, the oscillation frequency can be changed so that the oscillation frequency changes randomly. Furthermore, by setting up a magnetic tunnel junction array, problems such as yield and drift can be solved. In addition, by applying a negative write voltage to the magnetic tunnel junction, random number generation can be accelerated.

[0110] Based on the above embodiments, the second aspect of the present application further provides a random number generator. The random number generator provided by the present application is introduced below.

[0111] Specifically, the random number generator provided in the present application includes any random number oscillator based on a magnetic tunnel junction array provided in the first aspect of the present application.

[0112] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A random number oscillator based on a magnetic tunnel junction array, characterized in that: The random number oscillator includes a read / write selection circuit and a magnetic tunnel junction array; the magnetic tunnel junction array includes a plurality of magnetic tunnel junctions, the magnetic tunnel junctions include a parallel state and an anti-parallel state, the magnetic tunnel junctions have a first resistance value in the parallel state; the magnetic tunnel junctions have a second resistance value in the anti-parallel state; the first resistance value and the second resistance value are different; wherein, The read / write selection circuit is used to select a first magnetic tunnel junction in the magnetic tunnel junction array to enter a read operation in each oscillation cycle, and select a second magnetic tunnel junction in the magnetic tunnel junction array other than the first magnetic tunnel junction to enter a write operation when a preset write rule is satisfied, so that the resistance value of the magnetic tunnel junction array is randomly distributed between a first resistance value corresponding to the parallel state and a second resistance value corresponding to the anti-parallel state; The magnetic tunnel junction array is used as a current-type frequency determining element or a resistance-type frequency determining element in the random number oscillator, so that the oscillation frequency of the random number oscillator is controlled by the resistance value of the magnetic tunnel junction array, and the oscillation frequency of the oscillation signal generated by the random number oscillator is randomly switched between a first oscillation frequency corresponding to the first resistance value and a second oscillation frequency corresponding to the second resistance value through the random distribution of the resistance value between the first resistance value and the second resistance value; The read / write selection circuit is specifically used to sequentially control each magnetic tunnel junction in the magnetic tunnel junction array to enter a read state in each vibration cycle, and to control the next magnetic tunnel junction of the magnetic tunnel junction currently entering the read state to enter a write state in the current oscillation cycle.

2. The random number oscillator according to claim 1, characterized in that: The read / write selection circuit includes a voltage source circuit, a plurality of selection circuits, and a control circuit for providing control signals to the plurality of selection circuits; the number of the plurality of selection circuits is the same as the number of magnetic tunnel junctions included in the magnetic tunnel junction array, and each selection circuit is electrically connected to a magnetic tunnel junction; wherein, The voltage source circuit is used to provide a positive read voltage and a negative write voltage for each selection circuit; Each selection circuit is used to control the state of the magnetic tunnel junction connected to the selection circuit based on the control signal; wherein the state includes an isolation state, a read state and a write state; The control circuit is used to provide control signals to all selection circuits so as to select a first magnetic tunnel junction in the magnetic tunnel junction array to enter a read operation in each oscillation cycle, and to select a second magnetic tunnel junction in the magnetic tunnel junction array other than the first magnetic tunnel junction to enter a write operation when the current oscillation cycle satisfies a preset write rule.

3. The random number oscillator according to claim 2, characterized in that: The voltage source circuit includes a first voltage source for providing a positive read voltage and a second voltage source for providing a negative write voltage; each selection circuit includes a first selection circuit connected to the first voltage source and a second selection circuit connected to the second voltage source; The control circuit is used to provide control signals to the first selection circuit and the second selection circuit to control the state of the magnetic tunnel junction connected to the first selection circuit and the second selection circuit; wherein, when the magnetic tunnel junction is connected to the circuit through the first selection circuit, the first voltage source provides a forward read voltage to the magnetic tunnel junction to put the magnetic tunnel junction into a read state, and when the magnetic tunnel junction is connected to the circuit through the second selection circuit, the second voltage source provides a reverse write voltage to the magnetic tunnel junction to put the magnetic tunnel junction into a write state.

4. The random number oscillator according to claim 3, characterized in that: The first selection circuit includes a first analog switch and a second analog switch; wherein, The control ends of the first analog switch and the second analog switch are connected to form the control end of the first selection circuit, which is used to receive the control signal from the control circuit; A first end of the first analog switch is connected to a positive end of the first voltage source, and a second end of the first analog switch is connected to a positive end of a magnetic tunnel junction; A first end of the second analog switch is connected to the negative end of the magnetic tunnel junction, and a second end of the second analog switch is connected to the negative end of the first voltage source; The second selection circuit includes a third analog switch and a fourth analog switch; wherein, The control ends of the third analog switch and the fourth analog switch are connected to form the control end of the second selection circuit, which is used to receive a control signal from the control circuit; A first end of the third analog switch is connected to the positive end of the second voltage source, and a second end of the third analog switch is connected to the negative end of the magnetic tunnel junction; A first end of the fourth analog switch is connected to the positive end of the magnetic tunnel junction, and a second end of the fourth analog switch is connected to the negative end of the second voltage source.

5. The random number oscillator according to claim 4, characterized in that: The random number oscillator is a relaxation oscillator, and the relaxation oscillator further includes a current mirror circuit, a charge and discharge circuit, a comparator and a T trigger; wherein, The current mirror circuit is used to mirror the current formed by the read / write selection circuit and the magnetic tunnel junction array to the charge / discharge circuit, so as to charge the charge / discharge circuit with the current; The charging and discharging circuit is used to charge the capacitor in the charging and discharging circuit through the charging path in the charging state, and discharge the capacitor through the discharging path in the discharging state; The comparator is used to compare the capacitor voltage of the capacitor with a reference voltage and generate a comparison result; The T trigger is used to generate a state control signal for controlling the charge and discharge state of the charge and discharge circuit according to the comparison result, so as to control the charging path to be turned on when the capacitor voltage is less than the reference voltage so that the charge and discharge circuit enters the charging state, and to control the discharge path to be turned on when the capacitor voltage exceeds the reference voltage so that the charge and discharge circuit enters the discharge state.

6. The random number oscillator according to claim 5, characterized in that: The control circuit of the relaxation oscillator includes a counter and a decoder; wherein, The counter is used to record the triggering event in the state control signal and output the accumulated counting result; The decoder is used to convert the accumulated counting result into a control signal of a selection circuit connected to each magnetic tunnel junction in the magnetic tunnel junction array.

7. The random number oscillator according to claim 3 or 4, characterized in that: The control circuit is specifically used to sequentially control each magnetic tunnel junction in the magnetic tunnel junction array to enter a read state, and in a current oscillation cycle, control the next magnetic tunnel junction of the magnetic tunnel junction currently entering the read state to enter a write state.

8. The random number oscillator according to claim 2, characterized in that: The random number oscillator is a ring oscillator, the voltage source circuit includes a ring circuit composed of an odd number of NOT gates; the output end of each NOT gate is used to provide a positive read voltage or a negative write voltage to a magnetic tunnel junction array; the selection circuit includes a third selection circuit connected to the NOT gate; wherein, The third selection circuit includes a fifth analog switch and a sixth analog switch; wherein, The control ends of the fifth analog switch and the sixth analog switch are connected to form the control end of the third selection circuit, which is used to receive the control signal from the control circuit; The first end of the fifth analog switch constitutes the input end of the selection circuit, and the second end of the fifth analog switch is connected to the positive end of the magnetic tunnel junction; A first end of the sixth analog switch is connected to the negative end of the magnetic tunnel junction, and a second end of the sixth analog switch constitutes an output end of the selection circuit.

9. The random number oscillator according to claim 3, characterized in that: The random number oscillator is a relaxation oscillator, a Wien bridge oscillator, a phase shift oscillator, or a harmonic oscillator based on tail current control.

10. A random number generator, characterized in that: The random number generator comprises the random number oscillator according to any one of claims 1-9.

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