Magnetic latching relay driving circuit with arc extinguishing function

Abstract

The utility model provides a magnetic latching relay drive circuit with an arc extinguishing function. The magnetic latching relay drive circuit comprises an intermediate relay and an MOS tube. The intermediate relay and the MOS tube are both controlled by a control signal of the integrated chip; a first output contact of the intermediate relay is connected to a driving voltage input end of the magnetic latching relay; the second output contact of the intermediate relay is connected to the GND end of the magnetic latching relay through the MOS tube. According to the utility model, the MOS tube is designed between the intermediate relay and the magnetic latching relay, so that the contact switching of the intermediate relay can be completed firstly by controlling the output of the intermediate relay and the MOS tube, and then the MOS tube is opened; when the output polarity is switched, the MOS tube is firstly closed, then the contact of the intermediate relay is switched, and then the MOS tube is opened after the switching is completed, so that the switching logic of the two-stage sequential control ensures that the contact does not have inrush current and does not generate arc light.

Description

Technical Field

[0001] The utility model relates to the field of automatic control requiring driving of a magnetic latching relay, in particular to a magnetic latching relay driving circuit with an arc extinguishing function. Background Art

[0002] The magnetic latching relay is an automatic switch. Like other electromagnetic relays, it automatically connects and disconnects the circuit. The difference is that the normally closed or normally open state of the magnetic latching relay is completely dependent on the action of the permanent magnet, and the switching state conversion is completed by triggering a pulse electrical signal of a certain width.

[0003] In the current field of automatic control, there are many occasions where magnetic latching relays need to be driven, and there are several driving methods;

[0004] One is to use an integrated chip to drive, which has a small driving current, high cost, and limited usage scenarios; Figure 1 As shown in the figure, the current driving the magnetic latching relay depends on the output current of the driver chip. However, the driving current of general integrated chips is relatively small, and it is difficult to drive high-power magnetic latching relays;

[0005] Another method is to use an intermediate relay to drive directly, such as Figure 2 As shown, after adding an intermediate relay, a high-power magnetic latching relay can be driven. However, the magnetic latching relay is switched under power, which is very easy to sinter the relay contacts, resulting in reduced life and reliability. Moreover, the contacts are prone to arcing under high voltage. If the arc extinguishing function is not provided, the contacts are prone to burnout and damage after a period of use, resulting in control failure and further damage to the equipment. In order to extinguish the arc, some schemes have designed an arc extinguishing component, such as the Chinese utility model patent (publication number CN 217822596 U, entitled a magnetic latching relay capable of rapid arc extinguishing), which achieves arc extinguishing by installing a magnetic steel in a magnetic steel slot near the static contact to generate a magnetic field.

[0006] The above driving methods for magnetic latching relays can no longer meet the control requirements in terms of economy and reliability. Summary of the invention

[0007] In order to achieve the above object, a low-cost, high-reliability magnetic latching relay driving circuit with arc extinguishing function is provided.

[0008] The technical solution adopted by the utility model is:

[0009] The utility model provides a magnetic latching relay driving circuit with arc extinguishing function, comprising: an intermediate relay and a MOS tube; the intermediate relay and the MOS tube are both controlled by a control signal of an integrated chip;

[0010] The first output contact of the intermediate relay is connected to the driving voltage input terminal of the magnetic latching relay; the second output contact of the intermediate relay is connected to the GND terminal of the magnetic latching relay through the MOS tube.

[0011] Based on the above, the intermediate relay is a double-pole double-throw relay.

[0012] Based on the above, V_OUT is the driving voltage input terminal of the magnetic latching relay, V_OUT1 is the first output contact of the intermediate relay, V_OUT2 is the second output contact of the intermediate relay K1, JDQ_SWITCH is the control signal of the integrated chip to control the contact switching of the intermediate relay K1, and OUT_ON / OFF is the control signal of the integrated chip to control the on / off of the MOS tube Q2;

[0013] V_OUT is connected to pins 3 and 5 of the intermediate relay K1, pin 4 of the intermediate relay K1 is connected to V_OUT1, and pin 1 of the intermediate relay K1 is connected to V_OUT2; one end of the resistor R1 is connected to V_OUT1, the other end of the resistor R1 is connected to one end of the capacitor C1, and the other end of the capacitor C1 is connected to V_OUT2; pin 8 of the intermediate relay K1 is connected to +12V, pin 7 of the intermediate relay K1 is connected to the collector of the transistor Q1, pin 7 of the intermediate relay K1 is connected to the positive electrode of the diode D1, and pin 8 of the intermediate relay K1 is connected to the negative electrode of the diode D1;

[0014] The control signal JDQ_SWITCH is connected to one end of the resistor R4, the other end of the resistor R4 is connected to the base of the transistor Q1, the base of the transistor Q1 is connected to one end of the resistor R3, the other end of the resistor R3 is connected to the emitter of the transistor Q1, and the emitter of the transistor Q1 is connected to SGND;

[0015] The control signal OUT_ON / OFF is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the 2nd pin of the optocoupler U1, the 1st pin of the optocoupler U1 is connected to +3.3V, the 4th pin of the optocoupler U1 is connected to the cathode of the Zener diode D3, the anode of the Zener diode D3 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to the 3rd and 5th pins of the intermediate relay K1, one end of the capacitor C2 is connected to the cathode of the Zener diode D3, and the anode of the Zener diode D3 is connected to GND;

[0016] One end of the resistor R5 is connected to pin 3 of the optocoupler U1 and one end of the resistor R7, the other end of the resistor R7 is connected to GND, the other end of the resistor R5 is connected to the gate of the MOS tube Q2, the drain of the MOS tube Q2 is connected to pins 2 and 6 of the intermediate relay K1, the drain of the MOS tube Q2 is connected to one end of the TVS tube D2, the other end of the TVS tube D2 is connected to GND, the source of the MOS tube Q2 is connected to one end of the fuse F1, and the other end of the fuse F1 is connected to GND.

[0017] The utility model has substantial features and progress compared with the prior art, specifically:

[0018] The utility model designs a MOS tube between the intermediate relay and the magnetic latching relay, so that the output of the intermediate relay and the MOS tube can be controlled to complete the contact switching of the intermediate relay first, and then open the MOS tube; when switching the output polarity, the MOS tube is first closed, and then the contact switching of the intermediate relay is performed, and after the switching is completed, the MOS tube is opened. Such a switching logic of two-stage sequential control ensures that there is no inrush current at the contacts and no arc light is generated. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is an integrated chip driving solution.

[0020] Figure 2 It is an intermediate relay drive solution.

[0021] Figure 3 This is the driving solution of the utility model.

[0022] Figure 4 It is a specific driving circuit of the utility model. DETAILED DESCRIPTION

[0023] In order to more clearly understand the above-mentioned purpose, features and advantages of the utility model, the utility model is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0024] like Figure 3 As shown, this embodiment provides a magnetic latching relay driving circuit with arc extinguishing function, including: an intermediate relay and a MOS tube; the intermediate relay and the MOS tube are both controlled by a control signal of an integrated chip;

[0025] The first output contact of the intermediate relay is connected to the driving voltage input terminal of the magnetic latching relay; the second output contact of the intermediate relay is connected to the GND terminal of the magnetic latching relay through the MOS tube.

[0026] The specific circuit structure is as follows: Figure 4 As shown, V_OUT is the driving voltage input terminal of the magnetic latching relay, V_OUT1 is the first output contact of the intermediate relay, V_OUT2 is the second output contact of the intermediate relay K1, JDQ_SWITCH is the control signal of the integrated chip to control the contact switching of the intermediate relay K1, and OUT_ON / OFF is the control signal of the integrated chip to control the on / off of the MOS tube Q2;

[0027] V_OUT is connected to pins 3 and 5 of the intermediate relay K1, pin 4 of the intermediate relay K1 is connected to V_OUT1, and pin 1 of the intermediate relay K1 is connected to V_OUT2; one end of the resistor R1 is connected to V_OUT1, the other end of the resistor R1 is connected to one end of the capacitor C1, and the other end of the capacitor C1 is connected to V_OUT2; pin 8 of the intermediate relay K1 is connected to +12V, pin 7 of the intermediate relay K1 is connected to the collector of the transistor Q1, pin 7 of the intermediate relay K1 is connected to the positive electrode of the diode D1, and pin 8 of the intermediate relay K1 is connected to the negative electrode of the diode D1;

[0028] The control signal JDQ_SWITCH is connected to one end of the resistor R4, the other end of the resistor R4 is connected to the base of the transistor Q1, the base of the transistor Q1 is connected to one end of the resistor R3, the other end of the resistor R3 is connected to the emitter of the transistor Q1, and the emitter of the transistor Q1 is connected to SGND;

[0029] The control signal OUT_ON / OFF is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the 2nd pin of the optocoupler U1, the 1st pin of the optocoupler U1 is connected to +3.3V, the 4th pin of the optocoupler U1 is connected to the cathode of the Zener diode D3, the anode of the Zener diode D3 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to the 3rd and 5th pins of the intermediate relay K1, one end of the capacitor C2 is connected to the cathode of the Zener diode D3, and the anode of the Zener diode D3 is connected to GND;

[0030] One end of the resistor R5 is connected to pin 3 of the optocoupler U1 and one end of the resistor R7, the other end of the resistor R7 is connected to GND, the other end of the resistor R5 is connected to the gate of the MOS tube Q2, the drain of the MOS tube Q2 is connected to pins 2 and 6 of the intermediate relay K1, the drain of the MOS tube Q2 is connected to one end of the TVS tube D2, the other end of the TVS tube D2 is connected to GND, the source of the MOS tube Q2 is connected to one end of the fuse F1, and the other end of the fuse F1 is connected to GND.

[0031] Among them, the intermediate relay K1 is a double-pole double-throw relay, which is used to switch the polarity of the driving voltage required by the magnetic latching relay. Resistor R1 and capacitor C1 provide a discharge circuit for the high-voltage pulse between the contacts to protect the contacts. Transistor Q1 is used to drive the intermediate relay K1 and provide driving current for the coil of the intermediate relay K1; resistor R3 provides a pull-down resistor for the base of transistor Q1 to ensure that transistor Q1 is in the off state when there is no control signal; resistor R3 is a current limiting resistor for the base of transistor Q1. The optocoupler U1 is used to provide the gate drive isolation voltage of the MOS tube Q2, the resistor R6 is the current limiting resistor of the light emitting diode in the optocoupler U1, the resistor Zener diode D3 limits the gate voltage of the MOS tube Q2 to 5V, the resistor R2 is the current limiting resistor of the Zener diode D3, the capacitor C2 is the energy storage filter capacitor of the gate drive voltage of the MOS tube Q2, the MOS tube Q2 is the switch for outputting the drive voltage of the magnetic latching relay, the resistor R5 is the gate current limiting resistor of the MOS tube Q2, the resistor R7 is the gate-level pull-down resistor, and the fuse F1 provides overcurrent protection for the drive current of the magnetic latching relay; the TVS tube D2 is used to clamp the drive voltage of the magnetic latching relay and filter out high-voltage spike interference.

[0032] The specific control logic of the above circuit is that when the integrated chip outputs the control signal JDQ_SWITCH at a low level, no current flows through the coil of the intermediate relay K1, contact 4 is connected to contact 5, and contact 1 is connected to contacts 2 and 6. After a delay, the integrated chip outputs the control signal OUT_ON / OFF at a high level, and the MOS tube Q2 is turned on. At this time, the voltage on V_OUT1 is V_0UT, and the voltage on V_OUT2 is GND.

[0033] When the integrated chip outputs the control signal JDQ_SWITCH at a high level, current flows through the coil of the intermediate relay K1, contact 4 is connected to contacts 2 and 6, and contact 1 is connected to contact 3. After a delay, the integrated chip outputs the control signal OUT_ON / OFF at a high level, and the MOS tube Q2 is turned on. At this time, the voltage on V_OUT1 is GND, and the voltage on V_OUT2 is V_OUT.

[0034] Under the control of the integrated chip, the control signal JDQ_SWITCH controls the intermediate relay K1, and the control signal OUT_ON / OFF controls the MOS tube Q2, so that V_OUT and GND are switched to output on V_OUT1 and V_OUT2 respectively. The output logic of V_OUT1 and V_OUT is: when outputting, the contact switching of the intermediate relay is completed first, and then the MOS tube is turned on; when switching the output polarity, the MOS tube is closed first, and then the contact switching of the intermediate relay is performed. After the switching is completed, the MOS tube is turned on. Such a two-stage sequential control switching logic ensures that there is no inrush current at the contacts and no arcing occurs.

[0035] The above is only a specific implementation of the utility model, but the protection scope of the utility model is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the utility model, which should be included in the protection scope of the utility model. Therefore, the protection scope of the utility model should be based on the protection scope of the claims.

Claims

1. A magnetic latching relay driving circuit with arc extinguishing function, characterized in that: include: Intermediate relay and MOS tube; the intermediate relay and the MOS tube are both controlled by the control signal of the integrated chip; The first output contact of the intermediate relay is connected to the driving voltage input terminal of the magnetic latching relay; the second output contact of the intermediate relay is connected to the GND terminal of the magnetic latching relay through the MOS tube.

2. The magnetic latching relay driving circuit with arc extinguishing function according to claim 1, characterized in that: The intermediate relay is a double-pole double-throw relay.

3. The magnetic latching relay driving circuit with arc extinguishing function according to claim 2, characterized in that: V_OUT is the driving voltage input terminal of the magnetic latching relay, V_OUT1 is the first output contact of the intermediate relay, V_OUT2 is the second output contact of the intermediate relay K1, JDQ_SWITCH is the control signal of the integrated chip to control the contact switching of the intermediate relay K1, and OUT_ON / OFF is the control signal of the integrated chip to control the on / off of the MOS tube Q2; V_OUT is connected to pins 3 and 5 of the intermediate relay K1, pin 4 of the intermediate relay K1 is connected to V_OUT1, and pin 1 of the intermediate relay K1 is connected to V_OUT2; one end of the resistor R1 is connected to V_OUT1, the other end of the resistor R1 is connected to one end of the capacitor C1, and the other end of the capacitor C1 is connected to V_OUT2; pin 8 of the intermediate relay K1 is connected to +12V, pin 7 of the intermediate relay K1 is connected to the collector of the transistor Q1, pin 7 of the intermediate relay K1 is connected to the positive electrode of the diode D1, and pin 8 of the intermediate relay K1 is connected to the negative electrode of the diode D1; The control signal JDQ_SWITCH is connected to one end of the resistor R4, the other end of the resistor R4 is connected to the base of the transistor Q1, the base of the transistor Q1 is connected to one end of the resistor R3, the other end of the resistor R3 is connected to the emitter of the transistor Q1, and the emitter of the transistor Q1 is connected to SGND; The control signal OUT_ON / OFF is connected to one end of the resistor R6, the other end of the resistor R6 is connected to the 2nd pin of the optocoupler U1, the 1st pin of the optocoupler U1 is connected to +3.3V, the 4th pin of the optocoupler U1 is connected to the cathode of the Zener diode D3, the anode of the Zener diode D3 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to the 3rd and 5th pins of the intermediate relay K1, one end of the capacitor C2 is connected to the cathode of the Zener diode D3, and the anode of the Zener diode D3 is connected to GND; One end of the resistor R5 is connected to pin 3 of the optocoupler U1 and one end of the resistor R7, the other end of the resistor R7 is connected to GND, the other end of the resistor R5 is connected to the gate of the MOS tube Q2, the drain of the MOS tube Q2 is connected to pins 2 and 6 of the intermediate relay K1, the drain of the MOS tube Q2 is connected to one end of the TVS tube D2, the other end of the TVS tube D2 is connected to GND, the source of the MOS tube Q2 is connected to one end of the fuse F1, and the other end of the fuse F1 is connected to GND.

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