WO2013000361A1

WO2013000361A1 - Overvoltage protection module for dc circuit

Info

Publication number: WO2013000361A1
Application number: PCT/CN2012/076953
Authority: WO
Inventors: 陈石; 孙玉培; 许由生; 徐忠厚
Original assignee: 厦门赛尔特电子有限公司
Priority date: 2011-06-30
Filing date: 2012-06-15
Publication date: 2013-01-03
Also published as: CN202121318U

Abstract

Disclosed is an overvoltage protection module for a DC circuit, including a thermal cutoff fuse, a metal oxide varistor, and a gas discharge tube. The thermal cutoff fuse, metal oxide varistor, and gas discharge tube are connected in series successively inside a module; one end of the thermal cutoff fuse is used as a first pin, the connection point between the thermal cutoff fuse and the metal oxide varistor is used as a second pin; the connection point between the metal oxide varistor and the gas discharge tube is used as a third pin; and one end of the gas discharge tube is used as a fourth pin. Combining the thermal cutoff fuse (TCO), metal oxide varistor (MOV), and gas discharge tube (GDT) together and using the method of PCB board soldering can effectively reduce the volume of module occupied. Application in a DC power supply, and especially a 48 V communication DC power supply, effectively and securely protects against overvoltage surges.

Description

Overvoltage protection module for DC circuit

Technical field

The invention relates to an overvoltage protection module for a DC circuit, which comprises an alloy type temperature fuse, a varistor and a gas discharge tube.

Background technique

With its superior nonlinear volt-ampere characteristics, varistors are widely used as overvoltage protection and surge absorbing components for circuits, devices and components. Regardless of whether varistor is applied to power lines or electronic circuits, if various types of transient overvoltages occur frequently, the varistor will frequently operate to suppress overvoltage amplitude and absorb and release surge energy, protecting electrical equipment and Components. Thus, in the case of too frequent, this will inevitably lead to degradation or even failure of the varistor; thus, when the varistor receives a temporary overvoltage, the varistor will rapidly break down locally and cause a fire to burn. The varistor only has considerable limitations.

There is a need to improve the varistor circuit by avoiding the varistor combustion while properly protecting the circuit.

Summary of the invention

In view of the above requirements, the present invention provides an overvoltage protection module for a DC circuit, and the technical solution thereof is as follows:

An overvoltage protection module for a DC circuit, comprising a temperature fuse, a varistor and a gas discharge tube, wherein: the temperature fuse, the varistor and the gas discharge tube are sequentially connected in series in a module; a separate lead of the thermal fuse as a first pin; a junction of the thermal fuse and the varistor as a second pin; the varistor and the gas discharge tube are connected as a third pin; The independent lead of the gas discharge tube is used as the fourth pin; the first pin and the third pin are respectively connected to the negative pole and the positive pole of the DC power source, and the second pin and the fourth pin are respectively connected to the positive pole and the ground lead respectively ;

Wherein the varistor is in the form of a sheet, the conductive silver faces on both sides of the first and second electrodes are respectively soldered; the temperature fuse is in close contact with the surface of the first electrode, and the other lead of the thermal fuse crosses the And a varistor is connected to the second electrode and protrudes from the second pin; one end of the gas discharge tube is connected and fastened to the first electrode.

As a preferred embodiment of the present technical solution, improvements can be made in the following aspects:

In a preferred embodiment, the temperature fuse is an alloy type thermal fuse.

In a preferred embodiment, the exterior of the module has a protective outer casing.

In a preferred embodiment, the first and third pins are respectively connected to a negative pole and a positive pole of a 48V DC power supply, and the third pin is connected to a ground of a 48V DC power supply, and the second and third leads are respectively The foot is connected to a disconnection state indicating circuit of a thermal fuse.

As another type of the technical solution, it can be as follows:

The DC overvoltage protection module comprises a temperature fuse, a gas discharge tube and two varistor, wherein the varistor are all connected in parallel and then connected in series between the temperature fuse and the gas discharge tube. In the same module, the independent lead of the thermal fuse serves as a first pin; the junction of the thermal fuse and the varistor serves as a second pin; the varistor is connected to the gas discharge tube As a third pin; the independent lead of the gas discharge tube serves as a fourth pin;

Wherein, the first pin and the third pin are respectively connected to the negative pole and the positive pole of the DC power source, and the third electrode and the fourth electrode are respectively connected to the positive pole and the ground line;

The varistor is a first and a second varistor; the first varistor is in the form of a sheet, and the conductive silver faces on both sides are respectively soldered with the first and second electrodes; the second varistor Also in the form of a sheet, the conductive silver faces on both sides of the second electrode and the third electrode are respectively soldered; the first and third electrodes are connected structures;

The temperature fuse is in close contact with the first electrode surface of the first varistor; the other lead of the thermal fuse is connected to the second electrode across the first varistor, and extends the extension Two pins

The other end of the gas discharge tube is in close contact with and connected to the first electrode surface of the first varistor, and the third lead is externally led out on the third electrode.

As this other type of technical solution, it can be improved in the following aspects:

In a preferred embodiment, the thermal fuse is an alloy type thermal fuse.

The beneficial effects brought by the invention are:

The invention integrates a temperature fuse (TCO), a varistor (MOV) and a gas discharge tube (GDT) into one body, and adopts a PCB board welding method, which can effectively reduce the volume of the occupied module. The integrated module is used in a DC power supply, especially a 48V communication DC power supply, to effectively and safely protect against surge and overvoltage.

DRAWINGS

The present invention is further described below in conjunction with the embodiments of the drawings:

Figure 1 is a partial cross-sectional structural view showing a first embodiment of the present invention;

Figure 2 is a circuit diagram of a first embodiment of the present invention;

Figure 3 is a diagram showing the internal structure of a specific embodiment 1 of the present invention;

Figure 4 is a disassembled view of the component 301 built in the specific embodiment 1 of the present invention;

Figure 5 is a diagram showing the composition of a component 401 built in a specific embodiment 1 of the present invention;

Figure 6 is a partial cross-sectional structural view showing a second embodiment of the present invention;

Figure 7 is a circuit diagram of a second embodiment of the present invention;

Figure 8 is a view showing the internal structure of a second embodiment of the present invention;

Figure 9 is a disassembled view of the component 801 built in the second embodiment of the present invention;

Figure 10 is a diagram showing the composition of a component 901 built in a second embodiment of the present invention;

Figure 11 is a perspective view, taken along the line, of a third embodiment of the present invention;

Figure 12 is a disassembled view of the component 301 built in the third embodiment of the present invention;

Figure 13 is a view showing the composition of a component 401 built in a specific embodiment 3 of the present invention;

detailed description

Example 1:

The specific embodiment 1 of the present invention will be further described in conjunction with the accompanying drawings in which: FIG. 1 is intended to illustrate the preferred embodiments of the present invention and is not intended to limit the scope of the invention.

1 is a schematic view of a final assembly of a specific embodiment 1 of the present invention; the compact modular overall has four output pins, which are first to fourth pins from left to right, and are -48V terminals 508, The neutral line 506, the ground line 507, and the TCO disconnection indicate the circuit connection end 403.

In the circuit diagram shown in Figure 2, one TCO (temperature fuse) and one MOV (varistor) form a TMOV structure in series, which is formed in the TMOV module 401 in Figure 4; another gas discharge tube GDT is connected in series after TMOV The GDT module 402 in FIG. 4 is constructed. The TMOV module 401 and the GDT module 402 are structurally compactly combined to form the core 301 in FIG. 3, and the core 301 is placed in the housing 302 for fixing. The outer casing 302 is an injection molded engineering plastic or ceramic outer casing and then sealed with an epoxy resin, a silicone resin, an inorganic filler or the like. Of course, it is also possible to electrically and mechanically fix the outer casing 302 of the 301 by an integral encapsulation process of epoxy or silicone.

As shown in FIG. 4, the thermal fuse 401A is in close contact with the upper left corner of the TMOV module 401, and TMOV A gas discharge tube 402 is disposed on the right side of the module 401. The bottom electrode 404 of the gas discharge tube 402 has two mounting holes 405. The mounting holes 405 are sleeved and fixed on the first electrode 503 of the TMOV module 401. The raised portions 406 form an effective electrical connection and mechanical positioning, and the top electrode 403 on the gas discharge tube 402 externally leads out the fourth pin 403. Such an assembly minimizes the overall volume to meet the miniaturization of the overall product volume.

Figure 5 shows some details of the component TMOV module 401. On the ceramic die 501 of the MOV, two layers of

conductive silver layers

502A, 502B are applied to form the electrical characteristics of the MOV; the first electrode 503 is made of tin solder. The second electrode 504 is soldered to the

conductive silver layers

502A, 502B, respectively, and the second electrode 504 is soldered with a temperature fuse across the lead 505 and the second pin 506, which is bent across the lead 505 and spans both surfaces of the MOV. And forming a complete temperature fuse 401A on the outer side of the first electrode 503 with the temperature-sensitive alloy wire 511 of the thermal fuse, the first pin 508, the flux breaker 510, the fuse housing 512, and the sealing material 509; the fuse of the temperature fuse 401A The outer casing 512 has a contact surface (not shown) abutting against the first electrode 503 on the MOV; in order to improve the surge withstand capability of the thermal fuse 401A, the temperature-sensitive alloy wire 511 can adopt a plurality of parallel structures.

Example 2

The specific embodiment 2 of the present invention will be further described in conjunction with the accompanying drawings in the accompanying drawings, in which: FIG.

FIG. 6 is a schematic diagram of the assembly of the second embodiment of the present invention. The -48V end 1008, the neutral line 1006, the ground line 1007, and the TCO disconnect indication circuit connection end 903 in the physical module, that is, corresponding to the first and second, Third and fourth pins.

In the circuit diagram of FIG. 7, one TCO is connected in series with two MOVs connected in parallel to form a TMOV module 901 as shown in FIG. 9; and the other gas discharge tube GDT is connected in series with TMOV, and is shaped as a gas discharge tube in FIG. 902. The TMOV module 901 and the gas discharge tube 902 are structurally compactly combined to form the core 801 of FIG. 8, which is placed and fixed in the housing 802. The outer casing 802 is an injection-molded engineering plastic or ceramic outer casing, and then is sealed with an epoxy resin, a silicone resin, an inorganic filler or the like; or the core 801 is electrically insulated and mechanically sealed by an overall encapsulation process of epoxy resin or silicone resin. The fixed outer casing encloses to form the outer casing 802.

As shown in FIG. 9, the temperature fuse 901A is in close contact with the upper left corner of the TMOV module 901, and the TMOV module 901 The gas discharge tube 902 is disposed on the right side of the gas discharge tube 902. The bottom electrode 904 of the gas discharge tube 902 has two mounting holes 905, and the mounting holes 905 are respectively sleeved on the two convex portions 906 on the first electrode electrode 1003A. With effective electrical connection and mechanical positioning, the top electrode 903 on the gas discharge tube 902 leads out the fourth pin. Such an assembly minimizes the overall volume to meet the miniaturization of the overall product volume.

Figure 10 shows the details of the component TMOV module 901. On the first and second MOV ceramic dies 1001-1 and 1001-2, four-sided conductive silver layers 1002A, 1002B, 1002C, and 1002D are respectively coated to form electrical characteristics of the MOV; An electrode 1003A, an intermediate electrode 1004, and a fourth electrode 1003B are respectively soldered to the conductive silver layers 1002A, 1002B, 1002C, and 1002D, and the intermediate electrode 1004 includes a whole of the second and third electrodes, and is soldered over the lead 1005. And the second pin 1006, which is bent across the lead 1005 and spans the two surfaces of the MOV, and is on the outside of the first electrode 1003A with the temperature-sensitive fuse of the temperature-sensitive alloy wire 1011, the first pin 1008, the flux breaker 1010, and the outer casing. 1012. The sealing material 1009 is assembled into a complete thermal fuse 901A; the fuse housing 1012 of the thermal fuse 901A abuts the first electrode 1003A on the MOV.

Example 3:

11 to 13, the details of a specific embodiment 3 of the present invention are shown:

As shown in FIG. 1 , it is a schematic diagram of a general assembly of a third embodiment of the present invention; the compact modular whole has four output pins, which are respectively a first pin 508 connecting the -48V terminal and a second lead connecting the neutral wire. The leg 506, the third pin 507 connecting the ground, and the fourth pin 403 as the TCO disconnection indicating circuit connection, the entire core 301 is packaged in the outer casing 302, and the first to fourth pins are perpendicular to the outer casing 302 After the installation is completed, the outer casing 302 is placed on the mounting surface to form a horizontal shape.

In the circuit diagram shown in FIG. 12, one TCO (temperature fuse) and one MOV (varistor) constitute a TMOV structure connected in series, which is formed in the TMOV module 401 in FIG. 4; and another gas discharge tube GDT is connected in series to the TMOV module. After 401, the GDT module 402 of FIG. 12 is constructed. While the TMOV module 401 and the GDT module 402 are structurally compactly coupled together, the core 301 in FIG. 12 is constructed, and the core 301 is placed in the housing 302 of FIG. The outer casing 302 is an injection molded engineering plastic or ceramic outer casing and then sealed with an epoxy resin, a silicone resin, an inorganic filler or the like. It is also possible to electrically and mechanically fix the outer casing 302 of the 301 by an integral encapsulation process of epoxy or silicone.

The thermal fuse 401A is in close contact with the upper left corner of the TMOV module 401, while TMOV The gas discharge tube 402 is disposed in the lower right corner of the module 401. The bottom electrode 404 of the gas discharge tube 402 has two mounting holes 405. The mounting holes 405 are sleeved and fixed on the first electrode 503 of the TMOV module 401. The two raised portions 406 form an effective electrical connection and mechanical positioning, and the top electrode 403 on the gas discharge tube 402 is externally led out of the fourth fourth pin 403. Such an assembly minimizes the height of the crucible to meet the miniaturization of the overall product volume.

Figure 13 shows some details of the component TMOV module 401. On the ceramic die 501 of the MOV, two layers of conductive silver layers 502A, 502B are applied; the first electrode 503 and the second electrode 504 are soldered separately by tin solder. On the

conductive silver layer

502A, 502B, the second electrode 504 is soldered with a temperature fuse across the lead 505 and the second pin 506, which is bent across the lead 505 and spans both surfaces of the MOV and is outside the first electrode 503. The temperature-sensitive alloy wire 511, the first pin 508, the flux breaker 510, the fuse housing 512, and the sealing material 509 of the thermal fuse are assembled into a complete thermal fuse. 401A; The fuse housing 512 of the thermal fuse 401A has a contact surface (not shown) that abuts the first electrode 503 on the MOV.

The above is only the preferred embodiment of the present invention, and thus the scope of the present invention is not limited thereto, that is, equivalent changes and modifications made in accordance with the scope of the invention and the contents of the specification should still be covered by the present invention. Within the scope.

Industrial applicability

The thermal fuse (TCO), varistor (MOV) and gas discharge tube (GDT) are integrated into one body, and the PCB board welding method can effectively reduce the volume of the occupied module. It is used in DC power supply, especially 48V communication DC power supply, to effectively and safely protect against surge and overvoltage.

Claims

An overvoltage protection module for a DC circuit, comprising a temperature fuse, a varistor and a gas discharge tube, wherein: the temperature fuse, the varistor and the gas discharge tube are sequentially connected in series in a module; a separate lead of the thermal fuse as a first pin; a junction of the thermal fuse and the varistor as a second pin; the varistor and the gas discharge tube are connected as a third pin; The independent lead of the gas discharge tube is used as the fourth pin; the first pin and the third pin are respectively connected to the negative pole and the positive pole of the DC power source, and the second pin and the fourth pin are respectively connected to the positive pole and the ground lead respectively ;

Wherein the varistor is in the form of a sheet, the conductive silver faces on both sides of the first and second electrodes are respectively soldered; the temperature fuse is in close contact with the surface of the first electrode, and the other lead of the thermal fuse crosses the And a varistor is connected to the second electrode and protrudes from the second pin; one end of the gas discharge tube is connected and fastened to the first electrode.
The overvoltage protection module of a DC circuit according to claim 1, wherein the temperature fuse is an alloy type temperature fuse.
The overvoltage protection module for a DC circuit according to claim 1 or 2, wherein the module has a protective outer casing.
The overvoltage protection module of a DC circuit according to claim 1 or 2, wherein the first and third pins are respectively connected to a negative pole and a positive pole of a 48V DC power supply, and the third pin The ground wire of the 48V DC power supply is connected, and the second and third pins are connected to the disconnection state indicating circuit of the thermal fuse.
The DC overvoltage protection module comprises a temperature fuse, a gas discharge tube and two varistor, wherein the varistor are all connected in parallel and then connected in series between the temperature fuse and the gas discharge tube. In the same module, the independent lead of the thermal fuse serves as a first pin; the junction of the thermal fuse and the varistor serves as a second pin; the varistor is connected to the gas discharge tube As a third pin; the independent lead of the gas discharge tube serves as a fourth pin;

Wherein, the first pin and the third pin are respectively connected to the negative pole and the positive pole of the DC power source, and the third electrode and the fourth electrode are respectively connected to the positive pole and the ground line;

The varistor is a first and a second varistor; the first varistor is in the form of a sheet, and the conductive silver faces on both sides are respectively soldered with the first and second electrodes; the second varistor Also in the form of a sheet, the conductive silver faces on both sides of the second electrode and the third electrode are respectively soldered; the first and third electrodes are connected structures;

The temperature fuse is in close contact with the first electrode surface of the first varistor; the other lead of the thermal fuse is connected to the second electrode across the first varistor, and extends the extension Two pins

The other end of the gas discharge tube is in close contact with and connected to the first electrode surface of the first varistor, and the third lead is externally led out on the third electrode.
The overvoltage protection module of a DC circuit according to claim 5, wherein the temperature fuse is an alloy type temperature fuse.
An overvoltage protection module for a direct current circuit according to claim 5 or 6, wherein the outer portion of the module has a protective casing.
The overvoltage protection module of a DC circuit according to claim 5 or 6, wherein the first and third pins are respectively connected to a negative pole and a positive pole of a 48V DC power supply, and the third pin The ground wire of the 48V DC power supply is connected, and the second and third pins are connected to the disconnection state indicating circuit of the thermal fuse.