Non-volatile magnetic holding switch with temperature compensation

Abstract

The invention belongs to the field of electronic devices and manufacturing thereof, and particularly relates to a non-volatile magnetic holding switch with a temperature compensation function. A first magnetic core and a second magnetic core which are magnetized and saturated firstly, removed from an external magnetic field and completely identical are arranged, a winding is wound on the second magnetic core, and two windings are wound on the first magnetic core; one winding of the first magnetic core is completely the same as the winding on the second magnetic core, so that the temperature change of the first magnetic core is compensated through the second magnetic core, the sensing values and the impedance values of the two magnetic cores are enabled to have the same change, and the level amplitude of a point D does not change along with the temperature; the first magnetic core is controlled to be switched between a non-volatile remanence state II and a non-volatile demagnetization state IV through forward and reverse current pulses under the assistance of a comparator switching circuit, so that switching of a switch MOS (Metal Oxide Semiconductor) tube is realized; therefore, mechanical motion switch switching of an armature in an existing magnetic latching switch is replaced. The device is simple in structure, low in cost, nonvolatile, low in power consumption, high in response speed and resistant to mechanical shock; the magnetic latching switch is especially suitable for application scenarios of the magnetic latching switch with reliability and high integration, and has very important value.

Description

Technical Field

[0001] The invention belongs to the field of electronic devices and their manufacture, and in particular relates to a non-volatile magnetic holding switch with temperature compensation. Background Art

[0002] Magnetic latching switches (also known as latching relays or magnetically controlled switches) are widely used in various industrial and automation fields due to their unique non-contact operation, high reliability, and low power consumption. Their operating principle is based on electromagnetic induction and the retention of a magnetic field. They maintain a normally closed or normally open state through the action of a permanent magnet, while switching between switch states is triggered by a pulsed electrical signal. A key feature of this relay is that it maintains its state without requiring continuous power; a pulse signal is only applied when the state needs to change, resulting in energy-saving and efficient control.

[0003] The main structure of the magnetic holding switch consists of two parts, namely the electromagnetic system and the contact circuit (the structure is shown in the figure below). Figure 1 (as shown). The electromagnetic system consists of a magnet, armature, core, and coil. The contact circuit comprises a spring, reed, stator, and contacts. Due to the presence of a permanent magnet, a magnetic latching switch can remain open or closed for extended periods without consuming any power. To switch between states, simply pass a pulsed current in a specific direction through the coil. The magnet and pole piece form the armature assembly, which controls the opening and closing of the contact circuit via a push rod.

[0004] However, magnetic latching switches have a major drawback: they rely on the mechanical movement of an armature to switch. When subjected to significant mechanical vibration, shock, or acceleration, the armature can break free from the magnet and cause a false trip, leading to a switching error. To address this issue, the latching relay must incorporate numerous protective measures to mitigate the effects of external shocks. This not only significantly increases manufacturing costs but also makes it difficult to completely prevent false operation. Furthermore, traditional magnetic latching switches, which rely on the mechanical movement of the armature to switch, also suffer from slow response speeds. Summary of the Invention

[0005] In response to the above-mentioned problems or shortcomings, and to solve the problems of poor mechanical shock resistance and slow response speed of traditional magnetic latching switches, the present invention provides a non-volatile magnetic latching switch with temperature compensation and a preparation method thereof; compared with traditional magnetic latching switches, the device of the present invention has a simple configuration, low cost, fast response speed, non-volatility and strong mechanical shock resistance, and is of great value in application fields that have high requirements on shock resistance, reliability and environmental adaptability of magnetic latching switches.

[0006] A temperature-compensated, nonvolatile magnetic latching switch comprises a first magnetic core, a second magnetic core, and a comparator switch circuit. The first and second cores are made of identical materials, structural dimensions, and are both magnetized to saturation and free of external magnetic fields. Because the first core switches between only two stable, nonvolatile states: remanence (State II) and demagnetization (State IV), the second core must remain in the remanence state (State II) for optimal temperature compensation. Therefore, both cores are magnetized to saturation before use.

[0007] The first magnetic core is wound with two winding coils, wherein the first winding coil is used to apply bias current and bias magnetic field to the magnetic core, and the ends of the winding coil are A and B; the second winding coil is used to allow the magnetic core to obtain inductance and impedance, and the ends of the winding coil are C and D.

[0008] The second magnetic core is only wound with one winding coil, and the ends of the winding coil are D and E. The winding coils of the two magnetic cores (the first magnetic core and the second magnetic core) are connected through the end D; and the number of turns and the winding method of the winding coil are exactly the same as those of the second winding coil of the first magnetic core to ensure that the inductance and impedance values ​​of the two magnetic cores are consistent under the same conditions (at the same temperature after both are magnetized and saturated and the external magnetic field is removed).

[0009] The first winding coil of the first magnetic core is externally connected to a control current, which is a positive and reverse current pulse lasting 0.5 to 10 ms, used to control the first magnetic core to switch between the residual magnetization state II and the demagnetization state IV.

[0010] A fixed alternating voltage is connected between terminals C and E, D is the level sampling point, and terminal D is also connected to a comparator switch circuit: if the level amplitude at point D is higher than the level amplitude threshold preset by the comparator, the comparator switch circuit outputs a high level, the switch MOS tube connected to it is turned on, and the working circuit is turned on; if the level amplitude at point D is lower than the level amplitude threshold preset by the comparator, the comparator switch circuit outputs a low level, the switch MOS tube connected to it is turned off, and the working circuit is disconnected.

[0011] Furthermore, when the above-mentioned non-volatile magnetic holding switch with temperature compensation is used:

[0012] A reverse current pulse lasting 0.5 to 10 ms is applied to the first winding coil of the first magnetic core. The magnitude of the current pulse pulls the first magnetic core to a state III that is approximately demagnetized. After the current pulse is removed, the first magnetic core returns to state IV. In state IV, the magnetic permeability of the first magnetic core becomes that of the demagnetized state.

[0013] Since the second magnetic core is not affected by the pulse current, its inductance and impedance values ​​are still at the original value in the initial state II. At this time, the level of point D becomes lower due to the change of impedance voltage divider. Through the comparison between the comparator and the threshold level amplitude, the switch MOS tube in the comparator switch circuit is cut off.

[0014] When the overall switch needs to be switched again, a forward current pulse lasting 0.5 to 10 ms is applied to the first winding coil of the first magnetic core. The magnitude of this current pulse saturates the forward magnetization of the first magnetic core to state I. After that, due to the absence of current and bias field, the magnetic core will return to the original residual magnetization state II. At this time, the inductance and impedance values ​​of the first and second magnetic cores are the same, and the amplitude of the level at point D returns to the initial value. The comparator compares it with the threshold level, and the switch MOS tube in the comparator switching circuit is turned on.

[0015] That is, if the non-volatile state of the magnetic holding switch needs to be changed, the magnitude and direction of the pulse current at the A and B terminals are controlled to put the first magnetic core in different states (switching between the residual magnetization state II and the demagnetization state IV), so that the magnetic permeability of the magnetic core changes accordingly, and then the inductance and impedance of the right winding coil also change non-volatilely, thereby controlling the level state of point D to change; finally, the level change of point D is compared through the comparator switch circuit to realize the switching of the switch MOS tube in the comparator switch circuit.

[0016] Furthermore, the first magnetic core and the second magnetic core are toroidal magnetic cores.

[0017] Furthermore, the material of the magnetic core is preferably a magnetic material with soft magnetic properties. This is because of the design mechanism of the present invention, such as ferrite, magnetic powder core, amorphous / nanocrystalline, etc.

[0018] Furthermore, the magnetic core material is selected to have a magnetic core remanence ratio of ≥50%. The higher the remanence ratio, the greater the difference in magnetic permeability between state II and state IV, and the better the switching effect.

[0019] Furthermore, the magnitude of the pulse current used to switch the state of the first winding coil of the first magnetic core is adapted to the magnitude of the coercive field and saturation field of the magnetic core, the number of turns of the winding coil, and the size of the magnetic core, ensuring that the magnitude of the reverse pulse current demagnetizes the magnetic core, while the magnitude of the forward pulse current magnetizes and saturates the magnetic core. The magnitude of the reverse pulse current is optimal when it just demagnetizes the first magnetic core, while the magnitude of the forward pulse current is optimal when it magnetizes and saturates the first magnetic core.

[0020] The design working principle of the present invention:

[0021] The two magnetic cores (the first core and the second core) are made of exactly the same material and size, and have the same winding coils. A special second core is introduced to compensate for the temperature change of the first core: that is, when the temperature causes the magnetic permeability of the magnetic core to change, the inductance and impedance values ​​of the first and second cores will change in the same way, so that the voltage amplitude of point D will not change with temperature.

[0022] according to Figure 3 The figure shows the operating state of the magnetic cores. Initially, both cores are saturated and the external magnetic field is removed. As a result, the internal magnetization state of both cores changes from saturated state I to residual magnetization state II. At this point, the permeability (the permeability in the residual magnetization state) of the two cores is the same, and the inductance and impedance generated by the second winding of the first core are also the same. The voltage level at point D is equal to half the amplitude of the fixed voltage applied to CE. At this point, if a reverse current pulse (lasting 0.5 to 10 ms) is applied to the first winding of the first core, the current pulse magnitude is controlled to pull the first core to a state approximately demagnetized (state III). Subsequently, due to the absence of current and bias field, the first core returns to a position close to its origin (state IV). In state IV, the permeability of the first core returns to that of the demagnetized state. Clearly, the permeability in the demagnetized state (state IV) is significantly greater than that in the residual magnetization state (state II), resulting in a significant increase in the inductance and impedance of the second winding of the first core.

[0023] Since the second magnetic core is not affected by the pulse current, its inductance and impedance values ​​are still at the original value in the initial state II. At this time, the level of point D will become lower due to the change of impedance voltage divider. Through the comparison of the comparator and the threshold level amplitude, the switch MOS tube in the comparator switch circuit is cut off.

[0024] When the overall switch needs to be switched again, it is only necessary to apply a positive current pulse (the pulse duration is 0.5 to 10 ms) to the first winding coil of the first magnetic core. The size of the current pulse is controlled to be able to saturate the positive magnetization of the first magnetic core (that is, pull the magnetic core to the saturation state I). After that, due to the absence of current and bias field, the magnetic core will return to the original residual magnetization state II. At this time, the inductance and impedance values ​​of the first and second magnetic cores are the same, and the amplitude of the D point is restored to the initial value. The comparator is compared with the threshold level, and the switch MOS tube in the comparator switching circuit is turned on.

[0025] The main technical advantages of the present invention are as follows:

[0026] 1. Simple structure and low cost: The main structure of the non-volatile magnetic holding switch with temperature compensation includes two magnetic cores, one of which has two windings and the other has only one winding. The overall structure is very simple and the cost is very low.

[0027] 2. The switch state is non-volatile: that is, the residual magnetism (state II) and demagnetization (state IV) of the first magnetic core are both stable and non-volatile. Even if the system experiences a power outage during use, the state of the switch before the power outage can still be accurately determined.

[0028] 3. Low power consumption and fast response: The switch only requires a pulse of current to be applied to the first winding of the first magnetic core to switch states, which lasts only 0.5 to 10 milliseconds, resulting in very low energy consumption. Furthermore, because the non-volatile state is switched by changing the magnetization state, no mechanical movement is required, resulting in a very fast switching response speed, which can be 1 to 2 orders of magnitude faster than traditional magnetic latching switches.

[0029] 4. Resistance to mechanical shock: Since the magnetic latching switch of the present invention generates a magnetic field through a pulse current, and then changes the state of the magnetic core through the magnetic field, thereby causing the switching of the high and low levels and the disconnection of the MOS switch of the comparator, there is no mechanical movement in the whole process. Therefore, there is no problem of unstable magnetic adsorption and false switching caused by the armature of the traditional magnetic latching relay under shock or acceleration, which completely solves the "pain point" problem of the traditional magnetic latching relay switch. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Traditional magnetic latching switch model and physical diagram;

[0031] Figure 2 The main structure of the non-volatile magnetic holding switch of the present invention;

[0032] Figure 3 Schematic diagram of the working state of the first magnetic core. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below with reference to embodiments and accompanying drawings.

[0034] A non-volatile magnetic holding switch with temperature compensation, its main structure is as follows Figure 2 As shown, two cores with identical materials and dimensions are used. After both cores are saturated and the external magnetic field is removed, two windings are wound on each side of the first core. The left winding (the first winding coil) applies a bias current and magnetic field to the core, while the right winding (the second winding coil) ensures that the core has a specific inductance and impedance. The second core only needs to be wound with the right winding, using the same number of turns and method as the first core. This ensures that the inductance and impedance of the two cores are consistent under the same conditions (i.e., the same temperature, both cores are saturated, and the external magnetic field is removed).

[0035] like Figure 2As shown, a control current is connected to the coil on the left side of the first magnetic core, which controls the non-volatile state of the first magnetic core. The windings on the right sides of the two magnetic cores are connected together, and a fixed alternating voltage is connected between C and E. Point D is the level sampling point, and a comparator switch circuit is connected to point D. When the level amplitude at point D exceeds the comparator's preset level amplitude threshold, the comparator switch circuit is turned on. If the level amplitude at point D falls below the comparator's preset level amplitude threshold, the comparator switch circuit is turned off.

[0036] When the non-volatile state of the switch needs to be changed, it is only necessary to control the magnitude and direction of the current at terminals A and B to place the first magnetic core in a different magnetization state (switching between residual magnetization state II and demagnetization state IV). The magnetic permeability of the first magnetic core also changes accordingly, and the inductance and impedance of the right winding also undergo non-volatile changes, and the electrical level state of point D also changes. The switch is switched by comparing the electrical level changes at point D through a comparator switching circuit. Since the comparator switching circuit has a very mature technical solution and is not the innovation of the present invention, it will not be described in detail here.

[0037] In this embodiment, a ring-shaped magnetic core made of NiCuZn ferrite material is used to manufacture this non-volatile magnetic holding switch. The core size is 4mm (outer diameter) * 2mm (inner diameter) * 2mm (height). Figure 2 The circuit was connected, with 10 turns of wire wound on the left side of the first core and 10 turns on the right side, and 10 turns on the right side of the second core. Testing showed that applying a 1A current pulse to the left side of the first core generated a bias magnetic field of approximately 1150A / m, just enough to saturate the magnet. Applying a current pulse of approximately 200mA in the reverse direction generated a reverse bias magnetic field of approximately 230A / m, comparable to the coercive field of the magnet, and capable of demagnetizing it (State IV).

[0038] The table below shows the changes in inductance and impedance of the first core of this example after 10 switching cycles (tested at 1 MHz). The second core, used for temperature compensation, maintains a permeability of approximately 102.1 after saturation and demagnetization, an inductance of 2.83uH, and an impedance of 18.9Ω at 1 MHz.

[0039] Table 1 Changes in core permeability, inductance, and impedance with switching (1MHz)

[0040]

[0041] As can be seen, applying a reverse 200mA current pulse to the first core allows the wound core to enter a nonvolatile high-inductance, high-impedance state (State IV). Applying a forward 1A current pulse, however, allows the wound core to enter a nonvolatile low-inductance, low-impedance state (State II). Both states are stable and maintain excellent consistency across multiple switching cycles. Furthermore, the inductance and impedance values ​​of the two states are significantly different. In the low-inductance, low-impedance state (State II), the first core and the second core (used as a reference) have approximately equal inductance and impedance, resulting in a voltage amplitude at point D of approximately half the voltage amplitude across CE. If the voltage amplitude across CE is 1V, the voltage amplitude at point D is approximately 0.5V. When the first core is in the high-inductance, high-impedance state IV, the impedance of the first core is approximately 32.7Ω, while the impedance of the second core remains at 18.9Ω. At this point, the voltage amplitude at point D decreases to approximately 0.366V.

[0042] If the external comparator's threshold voltage is set to a value midway between its two states—here, 0.43V—then the comparator switches on when the voltage level at point D exceeds this threshold; it switches off when it falls below this threshold. This achieves nonvolatile switching. Even if the system loses power, the voltage level at point D remains at its previous nonvolatile state when power is restored, and the comparator can immediately switch to the corresponding on or off state.

[0043] As can be seen from the above embodiments, the present invention comprises two first and second magnetic cores, both of which are first magnetized and saturated and have their external magnetic field removed, and are made of exactly the same material and size. The second magnetic core is wound with one winding, and the first magnetic core is wound with two windings. One of the windings (the second winding) of the first magnetic core is exactly the same as the winding on the second magnetic core, thereby introducing a special second magnetic core to compensate for the temperature change of the first magnetic core, so that when the temperature causes the magnetic permeability of the magnetic core to change, the inductance and impedance values ​​of the first and second magnetic cores change in the same way, thereby ensuring that the level amplitude of point D does not change with temperature. A comparator switching circuit is then used to control the first magnetic core to switch between the non-volatile residual magnetic state II and the demagnetization state IV through positive and negative current pulses, thereby realizing the switching of the switching MOS tube. This replaces the mechanical movement switch switching of the armature in the existing magnetic holding switch. The present invention has a simple structure, low cost, non-volatility, low power consumption, fast response speed, and resistance to mechanical shock. It is particularly suitable for aerospace and other magnetic holding switch application scenarios with high requirements for reliability and integration, and has very important value.

Claims

1. A non-volatile magnetic latching switch with temperature compensation, characterized in that: comprising a first magnetic core, a second magnetic core and a comparator switch circuit; The first magnetic core and the second magnetic core are made of exactly the same material and have the same structure and size, and are both magnetized to saturation and the external magnetic field is removed; The first magnetic core is wound with two winding coils, wherein the first winding coil is used to apply a bias current and a bias magnetic field to the magnetic core, and the ends of the winding coil are A and B; the second winding coil is used to allow the magnetic core to obtain inductance and impedance, and the ends of the winding coil are C and D; The second magnetic core is wound with only one winding coil, whose terminals are D and E. The winding coils of the two magnetic cores are connected through terminal D. The number of turns and the winding method of the winding coil are exactly the same as those of the second winding coil of the first magnetic core, so as to ensure that the inductance and impedance values ​​of the two magnetic cores are consistent under the same conditions. The first winding coil of the first magnetic core is externally connected to a control current, wherein the control current is a positive and reverse current pulse lasting 0.5 to 10 ms, for controlling the first magnetic core to switch between the residual magnetization state II and the demagnetization state IV; A fixed alternating voltage is connected between terminals C and E, and D is the level sampling point. Terminal D is also connected to a comparator switch circuit: if the level amplitude at point D is higher than the preset level amplitude threshold of the comparator, the comparator switch circuit outputs a high level, the switch MOS tube connected to it is turned on, and the working circuit is turned on; If the level amplitude of point D is lower than the level amplitude threshold preset by the comparator, the comparator switch circuit outputs a low level, the switch MOS tube connected to it is disconnected, and the working circuit is disconnected.

2. The non-volatile magnetic holding switch with temperature compensation according to claim 1, characterized in that: When using: A reverse current pulse of 0.5 to 10 ms is applied to the first winding coil of the first magnetic core. The magnitude of the current pulse is such that the first magnetic core is pulled to a state III that is approximately demagnetized. After the current pulse is removed, the first magnetic core returns to state IV. In state IV, the magnetic permeability of the first magnetic core becomes that of the demagnetized state. Since the second core is not affected by the pulse current, its inductance and impedance values ​​are still at the original value in the initial state II. At this time, the level of point D becomes lower due to the change of the impedance voltage divider. After the comparator compares the level with the threshold level, the switch MOS tube in the comparator switch circuit is turned off. When the overall switch needs to be switched again, a forward current pulse lasting 0.5 to 10 ms is applied to the first winding coil of the first magnetic core. The magnitude of this current pulse saturates the forward magnetization of the first magnetic core to state I. After that, due to the absence of current and bias field, the magnetic core will return to the original residual magnetization state II. At this time, the inductance and impedance values ​​of the first and second magnetic cores are the same, and the amplitude of the level at point D returns to the initial value. The comparator compares it with the threshold level, and the switch MOS tube in the comparator switching circuit is turned on.

3. The temperature-compensated non-volatile magnetic holding switch according to claim 1, wherein: The first magnetic core and the second magnetic core are toroidal magnetic cores.

4. The temperature-compensated non-volatile magnetic holding switch according to claim 1, wherein: The material of the magnetic core is a magnetic material with soft magnetic properties.

5. The temperature-compensated non-volatile magnetic holding switch according to claim 4, wherein: The magnetic material with soft magnetic properties is ferrite, magnetic powder core or amorphous / nanocrystalline.

6. The non-volatile magnetic holding switch with temperature compensation according to claim 1, wherein: The magnetic core material is selected to have a magnetic core remanence ratio of ≥50%.

7. The temperature-compensated non-volatile magnetic holding switch according to claim 1, wherein: The magnitude of the pulse current for state switching of the first winding coil of the first magnetic core is adapted to the magnitude of the coercive field and saturation field of the magnetic core, the number of turns of the winding coil and the size of the magnetic core, ensuring that the reverse pulse current magnitude demagnetizes the magnetic core, while the forward pulse current magnitude magnetizes and saturates the magnetic core.

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