A magnetic latching relay contact automatic switching circuit at power-off moment and an electric device

Abstract

The utility model discloses a kind of magnetic latching relay lower power instantaneous contact automatic switching circuit and electrical equipment, belong to control circuit technical field, circuit includes system power supply, energy storage module, control module, trigger drive module and magnetic latching relay;The power supply end of system power supply and energy storage module is connected to the control coil of magnetic latching relay by the contact end of trigger drive module;The power supply end of system power supply is also connected to the charging end of energy storage module;Control module connects the control end of trigger drive module, for driving the contact end break of trigger drive module.Energy storage module stores electric energy when normal power on, power-off instant provides energy for trigger control module;Trigger control module acts on the control coil of magnetic latching relay, realizes the automatic switching of contact state.The utility model endows magnetic latching relay lower power instantaneous automatic switching contact function, using pure hardware logic design, not only circuit structure is simple, and reliability is high.

Description

Technical Field

[0001] This utility model relates to the field of control circuit technology, and in particular to an automatic contact switching circuit and electrical equipment for a magnetic latching relay at the moment of power-off. Background Technology

[0002] In modern electrical control systems, magnetic latching relays are widely used due to their unique advantages. Magnetic latching relays introduce permanent magnets, allowing the open and closed states of the contacts to be maintained by the magnetic force of the permanent magnets. They require a specific width pulse signal to trigger only during state transitions; the coil does not need to be energized under normal conditions. They are characterized by energy saving, stable performance, small size, and high load-bearing capacity.

[0003] Of particular concern is that existing magnetic latching relays generally fail to automatically switch contact states when a system experiences an abnormal power outage. This can lead to abnormal energization at the output after the system is powered on again, posing a significant safety hazard to subsequent equipment operation. In power distribution systems and industrial automated production lines, this abnormal energization can cause serious accidents such as equipment damage, short circuits, or even fires. Therefore, developing a circuit that can automatically switch contacts the instant a magnetic latching relay is powered off is urgently needed. This is crucial for improving the safety, stability, and reliability of electrical systems and expanding the application of magnetic latching relays in more complex and critical scenarios. Summary of the Invention

[0004] The purpose of this utility model is to overcome the shortcomings of the existing technology and provide an automatic contact switching circuit and electrical equipment for a magnetic latching relay at the moment of power failure. This solves the technical problem that the magnetic latching relay cannot switch contacts after an abnormal power failure, resulting in abnormal energization of the output terminal after power is restored, which causes safety hazards.

[0005] To achieve the above objectives, this utility model employs the following technical solution: In a first aspect, this utility model provides an automatic contact switching circuit for a magnetic latching relay upon power-off, comprising a system power supply, an energy storage module, a control module, a trigger drive module, and a magnetic latching relay; the power supply terminals of the system power supply and the energy storage module are both connected to the control coil of the magnetic latching relay through the contact terminals of the trigger drive module; the power supply terminal of the system power supply is also connected to the charging terminal of the energy storage module; the control module is connected to the control terminal of the trigger drive module and is used to drive the contact terminals of the trigger drive module to open and close.

[0006] Optionally, the energy storage module uses a capacitor, and the capacitance value of the capacitor is... C satisfy:

[0007] In the formula,E This is the energy required for switching magnetic latching relays. V The initial voltage of the capacitor is denoted as .

[0008] Optionally, the energy storage module uses a battery.

[0009] Optionally, the trigger drive module uses a switching transistor.

[0010] Optionally, the trigger drive module includes MOSFETs Q1, Q2, Q3 and resistors R1, R2, R3, R4, R5, R6; The control terminal of the trigger drive module is connected to the gate of the MOS transistor Q1 via the resistor R1. The gate of the MOS transistor Q1 is grounded via the resistor R4, and the source of the MOS transistor Q1 is grounded. The first contact of the trigger drive module is connected to the drain of the MOS transistor Q1 and one end of the resistor R2 via the resistor R5, and the other end of the resistor R2 is connected to the gate of the MOS transistor Q2. The first contact of the trigger drive module is connected to the gate of the MOS transistor Q3 and one end of the resistor R6 via the resistor R6, and the other end of the resistor R3 is connected to the drain of the MOS transistor Q2; the source of the MOS transistor Q2 is grounded. The first contact terminal of the trigger driving module is connected to the source of the MOS transistor Q3, and the second contact terminal of the trigger driving module is connected to the drain of the MOS transistor Q3.

[0011] Optionally, the MOSFETs Q1 and Q2 are NMOS transistors, the MOSFET Q3 is a PMOS transistor, the resistors R1, R2, and R3 are current-limiting resistors, the resistor R4 is a pull-down resistor, and the resistors R5 and R6 are pull-up resistors.

[0012] Optionally, the control module uses a microcontroller chip.

[0013] Optionally, a freewheeling diode is also connected in parallel to the control coil of the magnetic latching relay.

[0014] Secondly, this utility model provides an electrical device, including the aforementioned automatic contact switching circuit for a magnetic latching relay upon power-off.

[0015] Compared with the prior art, the beneficial effects achieved by this utility model are as follows: This utility model provides an automatic contact switching circuit and electrical equipment for a magnetic latching relay at the moment of power failure. Through the collaborative design of an energy storage module and a trigger drive module, the energy released by the energy storage module drives the magnetic latching relay contacts to switch at the moment of abnormal power failure of the system. This completely solves the safety hazard of traditional magnetic latching relays failing to automatically reset after abnormal power failure, resulting in abnormally energized output terminals when power is restored, and significantly improves the safety of the electrical system.

[0016] The trigger drive module adopts a pure hardware logic design, requiring no software intervention. When the system powers down normally, the control pin of the control module outputs a trigger signal to control the contact switching; when the system experiences an abnormal power failure, the control module's pin is forcibly pulled low, and the trigger drive module automatically uses the energy of the storage capacitor to complete the contact switching, achieving reliable switching covering all operating conditions.

[0017] Meanwhile, the circuit structure is simple, the cost is controllable, and the stability is good. Attached Figure Description

[0018] Figure 1 This is a topology diagram of the automatic contact switching circuit of the magnetic latching relay at the moment of power-off provided in Embodiment 1 of this utility model; Figure 2 This is a topology diagram of the automatic contact switching circuit of the magnetic latching relay at the moment of power-off provided in Embodiment 2 of this utility model. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0020] Example 1:

[0021] like Figure 1 As shown, this utility model embodiment provides an automatic contact switching circuit for a magnetic latching relay upon power-off, including a system power supply, an energy storage module, a control module, a trigger drive module, and a magnetic latching relay. The power supply terminals of both the system power supply and the energy storage module are connected to the control coil of the magnetic latching relay via the contact terminals of the trigger drive module; the power supply terminal of the system power supply is also connected to the charging terminal of the energy storage module; the control module is connected to the control terminal of the trigger drive module and is used to drive the contact terminals of the trigger drive module to open and close.

[0022] The energy storage module is mainly used to release energy to drive the switching of magnetic latching relay contacts in the instant of abnormal power failure of the system. Specifically, in this embodiment, the energy storage module adopts a capacitor or a battery. In other optional embodiments, those skilled in the art can also choose other forms of energy storage modules.

[0023] Taking a capacitor as an example, the capacitance value is selected based on the operating voltage of the magnetic latching relay control coil and the required driving energy, ensuring that sufficient power is provided to the drive unit to achieve contact switching after the circuit is powered off. Therefore, the capacitance value of the capacitor... C satisfy:

[0024] In the formula, E This is the energy required for switching magnetic latching relays. V The initial voltage of the capacitor is denoted as .

[0025] The trigger drive module uses switching transistors, including but not limited to MOSFETs, IGBTs, thyristors, or triodes.

[0026] Taking a transistor as an example, the control module is connected to the base of the transistor. The control module can be a microcontroller chip as needed. The power supply terminals of the system power supply and energy storage module are connected to the collector of the transistor. The emitter of the transistor is connected to the control coil of the magnetic latching relay. At the same time, the base of the transistor is also grounded through a pull-down resistor.

[0027] When the system power supply is working normally, the microcontroller chip outputs a high level to the base of the transistor, the transistor is cut off, the control coil of the magnetic latching relay is not energized, and the relay contacts remain in their original state; When the system power supply is working normally, the microcontroller chip outputs a low level to the base of the transistor, the transistor conducts, and the system power supply charges the energy storage module while simultaneously energizing the control coil of the magnetic latching relay through the transistor, causing the relay contacts to switch. When the system power fails, the microcontroller chip stops working. The pull-down resistor pulls the base of the transistor low, turning the transistor on. The energy storage module then powers the control coil of the magnetic latching relay through the transistor, causing the relay contacts to switch.

[0028] A freewheeling diode is also connected in parallel to the control coil of the magnetic latching relay. This diode provides a freewheeling circuit to the control coil of the magnetic latching relay when the trigger drive module (the transistor in this case) is turned off, thus protecting the trigger drive module.

[0029] Example 2:

[0030] like Figure 2As shown, in actual use cases, the system power supply is often 12V, and the control module only provides a 5V or 3.3V high level when using a microcontroller chip. In order to ensure the normal triggering of the trigger drive module, the trigger drive module is further extended in design based on the first embodiment. The trigger drive module includes MOSFETs Q1, Q2, and Q3 and resistors R1, R2, R3, R4, R5, and R6; MOSFETs Q1 and Q2 are NMOS transistors, MOSFET Q3 is a PMOS transistor, resistors R1, R2, and R3 are current-limiting resistors, resistor R4 is a pull-down resistor, and resistors R5 and R6 are pull-up resistors.

[0031] The connection is as follows: the control terminal of the trigger drive module is connected to the gate of MOSFET Q1 via resistor R1, the gate of MOSFET Q1 is grounded via resistor R4, and the source of MOSFET Q1 is grounded; the first contact terminal of the trigger drive module is connected to the drain of MOSFET Q1 and one end of resistor R2 via resistor R5, and the other end of resistor R2 is connected to the gate of MOSFET Q2; the first contact terminal of the trigger drive module is connected to the gate of MOSFET Q3 and one end of resistor R3 via resistor R6, and the other end of resistor R3 is connected to the drain of MOSFET Q2; the source of MOSFET Q2 is grounded; the first contact terminal of the trigger drive module is connected to the source of MOSFET Q3, and the second contact terminal of the trigger drive module is connected to the drain of MOSFET Q3.

[0032] Figure 2 The 12V VCC on the circuit serves as the system power supply, the signal IOO_RELAY is the output signal of the control module, and capacitor C1 serves as the energy storage module.

[0033] When the system power supply is normal, the signal IOO_RELAY is high, MOSFET Q1 is turned on, the gate of Q2 is low, MOSFET Q2 is turned off, MOSFET Q3 is turned off, the magnetic latching relay coil K1 is not energized, and the contacts remain in their original state.

[0034] When the system power supply is normal, the signal IOO_RELAY is at a low level, MOSFET Q1 is cut off, MOSFETs Q2 and Q3 are turned on, the magnetic latching relay coil K1 is energized, and the relay contacts are switched.

[0035] When the system power supply fails, the control module cannot complete the configuration of the signal IOO_RELAY and is in a floating state. The pull-down resistor R4 is forced to ground, and the energy stored in capacitor C1 maintains 12V for a short time. MOSFET Q1 is cut off, and MOSFETs Q2 and Q3 are turned on. The magnetic latching relay coil K1 is energized to switch the relay contacts.

[0036] The trigger drive module in this embodiment consists of only four MOSFETs (Q1-Q3), six resistors (R1-R6), one energy storage capacitor (C1), and one freewheeling diode (D1). Compared to existing technologies that rely on complex logic control or additional power supplies, this significantly reduces the number of components and circuit complexity, effectively lowering production costs and PCB space requirements. The circuit parameters can be adjusted to accommodate different specifications of magnetic latching relays by modifying the energy storage capacitor (C1) and the current-limiting resistor values ​​(R1-R6), offering broad compatibility and engineering practicality. It can be flexibly applied to circuit protection systems in industrial automation, smart homes, and new energy fields.

[0037] Example 3:

[0038] Based on the automatic contact switching circuit of the magnetic latching relay at the moment of power-off provided in Embodiment 1 or 2, this utility model embodiment further proposes an electrical device, including the above-described automatic contact switching circuit of the magnetic latching relay at the moment of power-off.

[0039] Those skilled in the art will understand that embodiments of this invention can be provided as methods, systems, or computer program products. Therefore, this invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this invention can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0040] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A circuit for automatic contact switching of a magnetic latching relay upon power-off, characterized in that, The system includes a system power supply, an energy storage module, a control module, a trigger drive module, and a magnetic latching relay. The power supply terminals of the system power supply and the energy storage module are both connected to the control coil of the magnetic latching relay through the contact terminals of the trigger drive module. The power supply terminal of the system power supply is also connected to the charging terminal of the energy storage module. The control module is connected to the control terminal of the trigger drive module and is used to drive the contact terminals of the trigger drive module to open and close.

2. The automatic contact switching circuit of the magnetic latching relay upon power-off as described in claim 1, characterized in that, The energy storage module uses a capacitor, and the capacitance value of the capacitor is... C satisfy: ； In the formula, E This is the energy required for switching magnetic latching relays. V The initial voltage of the capacitor is denoted as .

3. The automatic contact switching circuit of the magnetic latching relay upon power-off as described in claim 1, characterized in that, The energy storage module uses a battery.

4. The automatic contact switching circuit of the magnetic latching relay upon power-off as described in claim 1, characterized in that, The trigger drive module uses a switching transistor.

5. The automatic contact switching circuit of the magnetic latching relay upon power-off as described in claim 1, characterized in that, The trigger drive module includes MOSFETs Q1, Q2, and Q3 and resistors R1, R2, R3, R4, R5, and R6; The control terminal of the trigger drive module is connected to the gate of the MOS transistor Q1 via the resistor R1. The gate of the MOS transistor Q1 is grounded via the resistor R4, and the source of the MOS transistor Q1 is grounded. The first contact of the trigger drive module is connected to the drain of the MOS transistor Q1 and one end of the resistor R2 via the resistor R5, and the other end of the resistor R2 is connected to the gate of the MOS transistor Q2. The first contact of the trigger drive module is connected to the gate of the MOS transistor Q3 and one end of the resistor R6 via the resistor R6, and the other end of the resistor R3 is connected to the drain of the MOS transistor Q2; the source of the MOS transistor Q2 is grounded. The first contact terminal of the trigger driving module is connected to the source of the MOS transistor Q3, and the second contact terminal of the trigger driving module is connected to the drain of the MOS transistor Q3.

6. The automatic contact switching circuit of the magnetic latching relay at the moment of power-off as described in claim 5, characterized in that, The MOSFETs Q1 and Q2 are NMOS transistors, the MOSFET Q3 is a PMOS transistor, the resistors R1, R2, and R3 are current-limiting resistors, the resistor R4 is a pull-down resistor, and the resistors R5 and R6 are pull-up resistors.

7. The automatic contact switching circuit of the magnetic latching relay upon power-off as described in claim 1, characterized in that, The control module uses a single-chip microcontroller.

8. The automatic contact switching circuit of the magnetic latching relay upon power-off as described in claim 1, characterized in that, A freewheeling diode is also connected in parallel to the control coil of the magnetic latching relay.

9. An electrical appliance, characterized in that, Includes the automatic contact switching circuit of the magnetic latching relay at the moment of power-off as described in any one of claims 1-8.

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