WO2018084585A1

WO2018084585A1 - Open-mode protection device and electronic device having same

Info

Publication number: WO2018084585A1
Application number: PCT/KR2017/012301
Authority: WO
Inventors: 이재욱; 최재우; 조현진; 문지우
Original assignee: 주식회사 아모텍
Priority date: 2016-11-03
Filing date: 2017-11-02
Publication date: 2018-05-11

Abstract

An open-mode protection device and an electronic device having the same are provided. An open-mode protection device according to an embodiment of the present invention is an open mode protection device connected in parallel to each of a constant current source and a load comprising an LED. The open mode protection device comprises: a protection part connected to one side of a first lead frame and bypassing an overvoltage or an overcurrent; a current suppressing part having one side connected to a second lead frame and the other side connected in series to the other side of the protection part, and reducing the current of the protection part as the temperature or current of the protection part increases; and a molded part formed so as to surround the protection part and the current suppressing part.

Description

Open mode protection device and electronic device having same

The present invention relates to an open mode protection device, and more particularly, an open mode protection device for simultaneously implementing a function of suppressing abnormal overheating and excellent coupling stability of the protection device or simultaneously implementing a function of suppressing abnormal overheating and high withstand voltage. It relates to an electronic device.

Recently, lighting devices using LEDs having high power efficiency and easy control are becoming common. In particular, its use is rapidly increasing in fields such as backlight of display devices, various lamps of automobiles, and smart lighting using dimming.

Such LED lighting has a constant current lighting circuit that provides a constant current to a load consisting of LEDs. Here, a protection device is provided to protect a circuit when an electrostatic discharge (ESD), an electrical over stress (EOS), or a surge is introduced between the constant current source and the load.

In such a constant current type electronic device, when any one of the LEDs is damaged due to an electric shock and the load is opened, the currents of the constant current source all flow to the protection device, and the protection device is constantly overheated because the voltage of both ends continuously rises. Excessive ignition will cause fire.

Therefore, there is an urgent need to develop a technology capable of suppressing overheating of the protection device according to the open mode of the load along with the protection against ESD, EOS or surge against the LED load.

In addition, a method for integrally manufacturing different components for the protection function and the suppression function is required.

In addition, such protection devices require various breakdown voltages depending on the application to be applied, and in particular, development of a protection device having a high breakdown voltage is required.

The present invention has been made in view of the above points, and integrates an overcurrent or overvoltage protection function and a current suppression function to simultaneously prevent abnormal overheating of a protection device according to an open mode operation of a load, and simultaneously provide stability of coupling between dissimilar materials. It is an object of the present invention to provide an open mode protection device that can be implemented and an electronic device having the same.

Another object of the present invention is to provide a method of manufacturing an open mode protection device capable of simultaneously implementing a function of suppressing abnormal overheating of a protection device according to an open mode operation of a load and high withstand voltage to withstand high pressure by dividing a PPTC device. There is this.

In order to solve the above problems, the present invention provides an open mode protection device connected in parallel to a load consisting of a constant current source and an LED, respectively. The open mode protection device may include a protection unit connected to one side of a first lead frame and bypassing an overvoltage or an overcurrent; A current suppressing unit having one side connected to a second lead frame and the other side connected in series with the other side of the protection unit, and reducing the current of the protection unit as the temperature or current of the protection unit increases; And a molding part formed to surround the protection part and the current suppressing part.

According to a preferred embodiment of the present invention, the protective portion and the current suppressing portion may be coupled through a conductive adhesive layer.

In addition, the molding part may be made of an epoxy molding compound (EMC).

The protection unit and the current suppressing unit may be connected to each of the first lead frame and the second lead frame through solder.

The open mode protection device may further include a first external electrode connected to the first lead frame and formed at one side of the molding part; And a second external electrode connected to the second lead frame and formed on the other side of the molding part.

In this case, any one of the first external electrode and the second external electrode may be connected to one side of the constant current source and the load, and the other may be connected to the other side of the constant current source and the load.

In addition, the current suppressing unit may be made of a positive temperature coefficient (PTC) material or a polymeric positive temperature coefficient (PPTC) material.

In addition, the protection unit may be any one of a varistor, a suppressor, a gas discharge tube (GDT), and a diode.

In addition, the protection unit and the current suppressing unit may be vertically stacked on each other.

In addition, the current suppressing unit may be formed of a polymer layer in which the conductive filler is dispersed.

In addition, the conductive filler may be made of a carbon black material.

On the other hand, the present invention is a constant current source; A load consisting of LEDs driven by the constant current source; A ground terminal connected to one side of the constant current source and the load; And an open mode protection device as described above connected in parallel to the constant current source and the load, respectively, one side of which is connected to the ground terminal.

According to a preferred embodiment of the present invention, the constant current source may be any one of a constant current driver and a constant current power source.

On the other hand, the present invention is an open mode protection device connected in parallel to the load consisting of a constant current source and LED, respectively, a varistor having one side connected to the first lead frame; A PPTC substrate having one side connected to a second lead frame and the other side connected in series with the other side of the varistor; A conductive adhesive layer coupling the other side of the varistor and the other side of the PPTC substrate; A molding part formed to surround the varistor and the PPTC substrate; A first external electrode connected to the first lead frame and formed on one side of the molding part; And a second external electrode connected to the second lead frame and formed on the other side of the molding part.

According to the present invention, by vertically stacking and integrating a current suppressing portion made of a PTC element or a PPTC element and a protection element, a function of suppressing abnormal overheating of the protection element and coupling stability can be simultaneously realized, thereby increasing the temperature or current of the protection element. While suppressing and thus preventing damage of the protection element itself due to abnormal overheating, it is possible to easily utilize the manufacturing process to improve manufacturing efficiency and to realize low cost.

In addition, the present invention by mounting the current suppressing unit and the protection element to each of the lead frame and then bonded using a conductive adhesive layer, the process is simplified, it is possible to apply the existing product can be easy to mass production.

In addition, the present invention suppresses abnormal overheating of the protection element itself, thereby preventing damage to adjacent circuit components as well as preventing fire due to ignition of the protection element.

In addition, the present invention by forming a slit on a large-area PPTC substrate and mounting the protective element with the slit in between, it is possible to realize the function of suppressing abnormal overheating and high withstand voltage of the protective element at the same time, thereby increasing the temperature or current of the protective element It is possible to reduce the thickness and prevent the damage of the protection element itself due to abnormal overheating, while reducing the thickness of the material in order to increase the internal pressure, thereby realizing thinning.

In addition, the present invention improves the reliability of the product by filling the molding member in the slit of the large area PPTC substrate, thereby improving the deterioration of strength due to the slit and improving the bonding force between the PPTC substrate and the protection element in the unit device. You can.

In addition, the present invention forms a slit on a large area PPTC substrate to mount the protection element, it is possible to mass production and easy adjustment of the size of the product can provide flexibility in standardization.

1 is a cross-sectional view of an open mode protection device according to a first embodiment of the present invention;

2 is a perspective view of the open mode protection device of FIG.

3 is an exploded cross-sectional view illustrating a lamination relationship of the open mode protection device of FIG. 1;

4 is an equivalent circuit diagram of the open mode protection device of FIG. 1;

5 is a plan view showing a large area lead frame,

6 is a plan view illustrating a state in which a current suppressing unit or a protecting unit is mounted on a large area lead frame;

FIG. 7 is a perspective view illustrating a state in which a current suppressing unit and a protecting unit respectively mounted on a large area lead frame are bonded through a conductive adhesive layer;

8 is a perspective view showing a state before molding by the EMC sheet,

9 is a cross-sectional view showing a molded state by pressure and thermal welding of an EMC sheet,

10 and 11 are a perspective view and a cross-sectional view showing a position to cut the molding assembly,

12 is a graph showing temperature characteristics of the open mode protection device of FIG. 1;

13 is a schematic structural diagram of an electronic device having an open mode protection device according to a first embodiment of the present invention;

14 is a view for explaining the normal operation of the load in the electronic device of FIG.

FIG. 15 illustrates an open mode operation of a load in the electronic device of FIG. 13; FIG.

16 is a flowchart of a method of manufacturing an open mode protection device according to a second embodiment of the present invention;

17 is a perspective view showing a state in which slits are formed on a large area substrate;

18 and 19 are a perspective view and a cross-sectional view showing a state in which a thin protective element is mounted;

20 is a perspective view showing a state before molding by an epoxy sheet;

21 and 22 are a perspective view and a cross-sectional view showing a molded state by pressing and heat fusion of the epoxy sheet,

23 and 24 are a perspective view and a cross-sectional view showing a position to cut a molded large area substrate,

25 is a cross-sectional view of a unit device manufactured by a method of manufacturing an open mode protection device according to a second embodiment of the present invention; and

FIG. 26 is an equivalent circuit diagram of the open mode protection device of FIG. 25.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. The drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification.

The open mode protection device 100 according to the first embodiment of the present invention includes a protection unit 110, a current suppressing unit 120, and a molding unit 130 as shown in FIGS. 1 to 3. .

The open mode protection device 100 is connected in parallel to a load consisting of a constant current source and an LED, respectively, and bypasses an ESD, EOS or surge current flowing from the outside to the ground, thereby protecting a circuit including the constant current source and the load.

The protection unit 110 is connected to the first lead frame 106 through one side of the electrode 112 and bypasses overvoltage or overcurrent. That is, the protection unit 110 may bypass the first external electrode 102 or the second external electrode 104 to the ground by passing an overvoltage or overcurrent caused by ESD, EOS, or surge flowing from the outside. .

In addition, the protection unit 110 bypasses the constant current of the constant current source to ground through the first external electrode 102 or the second external electrode 104 during the open mode operation of the load made of the LED.

Here, the protection unit 110 may be a single component manufactured. For example, the protection unit 110 may be any one of a varistor, a suppressor, a gas discharge tube (GDT), and a diode, but is not particularly limited thereto, and may bypass the overvoltage or the overcurrent. It may include a device.

The protection unit 110 may include a varistor material layer. That is, the body 110a of the protection unit 110 may be made of a varistor material.

As another example, the body 110a may be made of a body. The body is ZnO, BaTiO _3, and SrTiO include one or more of the _3, and Pr, Bi, Ni, Mn, Cr, Co, Sb, Nd, Si, Ca, La, Mg, Al, Ti Sn, Nb, and At least one of Y may be included as a dopant.

In this case, the protection unit 110 may have the electrode 112 connected to the first lead frame 106 through solder or epoxy solder. That is, the protection unit 110 may be mounted on the first lead frame 106 through an SMT soldering process. Here, the first lead frame 106 may be exposed to the outside of the molding unit 130 so that one end thereof is connected to the first external electrode 102.

In addition, the protection unit 110 may be formed with

electrodes

112 and 114 on the upper and lower surfaces, respectively. The protection unit 110 may be a vertical type. That is, the internal electrode of the protection unit 110 may be disposed in a vertical form between the

electrodes

112 and 114.

The current suppressing unit 120 has one electrode 124 connected to the second lead frame 108, and the other electrode 122 is connected to the other electrode 114 of the protection unit 110 through the conductive adhesive layer 109. It is connected in series and reduces the current of the protection unit 110 as the temperature or current of the protection unit 110 increases.

That is, the current suppression unit 120 senses the temperature or current of the protection unit 110, and when the load is opened by any one of the plurality of LEDs to be protected, the current provided from the constant current source is protected. As the temperature or current of the protection unit 110 increases while flowing to the unit 110, the current of the protection unit 110 is reduced.

Here, the current suppressing unit 120 may be a single component manufactured. For example, the current suppression unit 120 may be any one of a polymer positive temperature coefficient (PPTC) device and a positive temperature coefficient (PTC) device. That is, the current suppressing unit 120 may be made of a PTC material or a PPTC material.

In addition, when the current suppressing unit 120 is a PPTC device, the current suppressor 120 may include a polymer layer having conductive fillers dispersed therein. That is, in the current suppressing unit 120, the base layer 120a may be formed of a polymer layer. In this case, the conductive filler may be made of a carbon black material.

The current suppressing unit 120 may have the electrode 124 connected to the second lead frame 108 through solder or epoxy solder. That is, the current suppressing unit 120 may be mounted on the second lead frame 108 through an SMT soldering process. Here, the second lead frame 108 may be exposed to the outside of the molding unit 130 so that one end thereof is connected to the second external electrode 104.

The protection unit 110 and the current suppressing unit 120 may be vertically stacked on each other through the conductive adhesive layer 109. Here, the conductive adhesive layer 109 may be made of any one of Ag-epoxy, epoxy solder and solder.

Through this, coupling between the protection unit 110 and the current suppressing unit 120 made of different materials can be easily achieved. That is, the

electrodes

112 and 114 may be formed through the conductive adhesive layer 109 without directly stacking or bonding the body 110a of the protection unit 110 made of different materials and the base layer 110a of the current suppressing unit 120. And by stacking through the

electrodes

122, 124, it can be easily and stably coupled between the protection unit 110 and the current suppressing unit 120.

In addition, since a process of soldering each of the protection unit 110 and the current suppressing unit 120 to the lead frame and then bonding through the conductive adhesive layer 109 is available, it is easy to utilize the manufacturing process to improve the manufacturing efficiency and low cost. Can be implemented.

Furthermore, by mounting the current suppression unit 120 and the protection unit 110 to the lead frame using the SMT process, and then combining the respective using the conductive adhesive layer 109, the manufacturing process is simplified, mass production It may be easy.

The molding part 130 protects the protection part 110 and the current suppressing part 120 and is formed to completely surround the outside of the protection part 110 and the current suppressing part 120 in order to package it into a single device.

That is, the molding part 130 includes not only the protection part 110 and the current suppressing part 120, but also the conductive adhesive layer 109, the first lead frame 106, and the second lead frame 108 are embedded therein. It may be formed to completely wrap. Here, the molding part 130 may be made of an epoxy molding compound (EMC) as an example. As another example, the molding part 130 may be formed by a single or a mixture of a phenol-based resin and a polyimide-based high heat resistant film.

Through this, the coupling force between the protection unit 110 and the current suppressing unit 120 may be further improved. That is, although the protection unit 110 and the current suppressing unit 120 are coupled through the conductive adhesive layer 109, since the bonding force is lowered due to peeling of the conductive adhesive layer 109, the protection unit 110 and the current suppression are prevented. By fixing all sides of the part 120 with the molding part 130, the coupling stability between the protection part 110 and the current suppressing part 120 may be further improved.

In this case, the molding unit 130 has an end portion of the first lead frame 106 and one end of the second lead frame 108 to be connected to the first external electrode 102 and the second external electrode 104. It may be formed to be exposed to the outside of the 130.

Meanwhile, the open mode protection device 100 of the present invention may further include a first external electrode 102 and a second external electrode 104.

The first external electrode 102 is connected to the first lead frame 106 and may be formed on one side of the molding part 130. The first external electrode 102 may be connected to the protection unit 110 through the first lead frame 106.

Here, the first external electrode 102 is connected to one side of the constant current source and the load. That is, the first external electrode 102 may be connected to a point where one side of the constant current source and one side of the load are connected.

The first external electrode 102 is connected to the second lead frame 108 and may be formed on the other side of the molding unit 130. The second external electrode 104 may be connected to the current suppressing unit 120 through the second lead frame 108.

Here, the second external electrode 104 is connected to the other side of the constant current source and the load. That is, the second external electrode 104 may be connected to a point at which the other side of the constant current source is connected to the other side of the load.

In this case, one end of the first lead frame 106 and the second lead frame 108 may be exposed to the outside of the molding unit 130 and may be connected to the first external electrode 102 and the second external electrode 104, respectively. .

Here, although the first external electrode 102 is shown and described as being connected to the protection unit 110 and the second external electrode 104 is connected to the current suppressing unit 120, it will be understood that the opposite connection can be made. . That is, the first external electrode 102 may be connected to the current suppressing unit 120, and the second external electrode 104 may be connected to the protection unit 110.

As shown in FIG. 4, the open mode protection device 100 may be represented by an equivalent circuit in which a protection unit B such as a varistor and a current suppressing unit P such as a PPTC device or a PTC device are connected in series.

That is, in the open mode protection device 100, one end of the current suppression unit P is connected to one external terminal, and one end of the protection unit B is connected to the other external terminal, and the current suppression unit P is provided. By connecting the other end of the other end of the protection unit (B) with each other, the current suppressing unit (P) and the protection unit (P) can be connected in series with respect to the external terminal.

The open mode protection device 100 according to the first embodiment of the present invention configured as described above has a low resistance value at a temperature of 80 ° C. to 120 ° C., as shown in FIG. 12. That is, the open mode protection device 100 may function as a protection device such as a varistor to protect the circuit by bypassing ESD, EOS or surge flowing into the static electricity or the load to ground.

In addition, when a load made of LED is opened by ESD, EOS, or surge from the outside, the current and voltage flowing to the open mode protection device 100 continuously increase, thereby overheating the protection unit 110. That is, when the load is opened because the power of the load is a constant current source, all currents of a constant magnitude provided from the constant current source flow to the open mode protection device 100. At this time, the actual load of the constant current source is the open mode protection device 100, and in this case, a constant magnitude of current flows from the constant current source to the open mode protection device 100, which is a condition that the voltage rises to infinity.

For example, when the load is in an open state, as the voltage across the open mode protection device 100 which is a substantial load rises to the supply power level (200 to 300V), the open mode protection device 100, in particular, the protection unit ( 110) is overheated.

At this time, when the open mode protection device 100 is overheated at a temperature of 150 ° C to 200 ° C, the open mode protection device 100 increases the amount of current flowing in the open mode protection device 100 due to a sudden increase in resistance of the current suppressing unit 120. By reducing the voltage, the voltage at both ends of the protection unit 110 can be reduced to reduce the temperature, thereby suppressing heat generation. Accordingly, self damage due to overheating of the protection unit 110 can be prevented.

Referring to the manufacturing method of such an open mode protection device 100, first, as shown in FIG. 5, a large area lead frame 150 having a plurality of slits 152 formed at a predetermined interval is prepared. Here, the slits 152 have a comb shape in the longitudinal direction, and the space portion 106a between the slits 152 is a space for mounting the protection unit 110 or the current suppressing unit 120.

That is, as shown in FIG. 6, the protection unit 110 or the current suppressing unit 120 is mounted in the space portion 106a between the slits 152. Here, the protection unit 110 or the current suppressing unit 120 may be disposed to be approximately centered in the space 106a.

In this case, the protection unit 110 or the current suppressing unit 120 may be mounted on the space portion 106a of the large area lead frame 150 through the SMT soldering process. That is, the protection unit 110 or the current suppressing unit 120 may be soldered or epoxy to the space portion 106a of the large area lead frame 150 corresponding to the first lead frame 106 and the second lead frame 108. It can be connected via solder.

As such, the large-area lead frame 150a having the protection unit 110 and the current suppressing unit 120 mounted thereon is stacked on each other through the conductive adhesive layer 109. That is, as shown in FIG. 7, an example of the conductive adhesive layer 109 is disposed between the protection unit 110 and the current suppression unit 120 so as to face each other of the large-area lead frame 150a mounted therebetween. As an Ag-epoxy sheet 109a, the protection unit 110 and the current suppressing unit 120 can be laminated in combination. Here, although the Ag-epoxy sheet 109a is illustrated and described as being composed of one sheet of a large area, the Ag-epoxy sheet 109a may be divided into the sizes of the electrodes of the protection unit 110 and the current suppressing unit 120 that are stacked.

Next, a molding member is molded to completely surround the protection unit 110 and the current suppressing unit 120 mounted on the large area lead frame 150a. In this case, the molding member may be made of an epoxy molding compound (EMC).

For example, as illustrated in FIG. 8, the EMC sheet 130a may be disposed above and below the large area lead frame 150a to be thermally fused while pressing toward the large area lead frame 150a.

Through this, the molding member 130 ′ melted by heat may be molded to fill the upper side and the lower side of the large-area lead frame 150 and therebetween. That is, as shown in FIG. 9, the molten molding member 130 ′ is formed between the large area lead frame 150a through the respective slits 152 from the upper side and the lower side of the large area lead frame 150. The protection unit 110 and the current suppressing unit 120 may be introduced into the mounted area.

Here, the large area lead frame 150a, the protection unit 110, and the current suppression unit 120 are molded by pressing and heat-sealing the EMC sheet 130a, but various molding members and molding methods are not limited thereto. Note that it can be molded with.

For example, as the molding member, a phenol-based resin and a polyimide-based high heat resistant film may be used singly or in combination.

In addition, coupling agents or rubber-based mixed polymers can be used for proper work processes, and additional surface treatment can be performed to improve adhesion and reliability of bodies such as varistors. have.

Next, the molded large area leadframe 150a is cut into a unit device including one structure in which the protection unit 110 and the current suppressing unit 120 are vertically stacked.

As shown in FIGS. 10 and 11, the molded large area leadframe 150a may be cut along the longitudinal transmission line a and the width cutting line b corresponding to the size of the unit device.

Through this, the open mode protection device 100, which is a unit device as shown in FIG. 1, may be completed.

At this time, the first external electrode 102 and the second external electrode 104 connected to the first lead frame 106 and the second lead frame 108 that are exposed to the outside of the molding unit 130, the molding unit 130. Can be formed on both sides of the).

Here, the first external electrode 102 and the second external electrode 104 may be plated. For example, the first external electrode 102 and the second external electrode 104 may be plated with one of Ag, Pt, and Au.

Through this, the electrical conductivity of the first external electrode 102 and the second external electrode 104 may be improved, and the first external electrode 102 and the second external electrode 104 may be formed to prevent wear or corrosion. I can protect it.

The open mode protection device 100 according to the first embodiment of the present invention can be used in an electronic device having a load consisting of a constant current source and an LED.

As shown in FIG. 13, the electronic device 1 may include a constant current source 10, an LED load 12, and an open mode protection device 100.

Here, the electronic device 1 is a device having an LED as a load, and may be any one of a backlight (BLU) of a display device such as a TV, various lamps of a vehicle, and smart lighting using dimming.

The constant current source 10 may supply a constant current to the LED load 12. The constant current source 10 may be any one of a constant current power supply and a constant current driver. That is, the constant current source 10 is not limited to a particular form, and may be a source for supplying current in a constant current manner, for example, a power source for supplying power to the electronic device 1 or driving the LED load 12. It may be a driving unit for.

LED load 12 may be composed of a plurality of LEDs. Here, the LED load 12 may be connected in series with a plurality of LEDs, but is not limited thereto. For example, the LED load 12 may be a plurality of LEDs are connected in series, a plurality of LEDs in series may be connected in parallel, or a plurality of LEDs may be connected in parallel, a plurality of LEDs in parallel may be connected in series. .

The LED load 12 may have a constant voltage value while the LED is turned on to supply a predetermined amount of current from the constant current source 10. For example, when the constant current source 10 supplies a current of 400 mA and the LED load 12 consists of ten LEDs, a voltage of approximately 25 to 30 V may be output at both ends of the load.

Here, one side of the constant current source 10 and the LED load 12 is connected to the ground terminal. That is, the cathode side of the constant current source 10 and the load 12 may be connected to the ground terminal. The ground terminal may be connected to a common ground formed on the circuit board of the electronic device 1.

The open mode protection device 100 may be connected in parallel to the constant current source 10 and the LED load 12, respectively. That is, one side of the open mode protection device 100 may be connected to one side of the constant current source 10 and the LED load 12, and the other side thereof may be connected to the other side of the constant current source 10 and the LED load 12. . In this case, one side of the open mode protection device 100 may be connected to the ground terminal.

As such, when the LED load 12 is in a normal operation state and the ESD, EOS, or surge flows into the LED load 12 from the outside, as shown in FIG. The current (i _ESD ) corresponding to ESD, EOS, or surge flows to 100 and consequently bypasses the ground terminal, thereby protecting the LED load 12 from ESD, EOS, or surge.

That is, since the resistance of the current suppression unit 120 such as the PPTC device or the PTC device is very small, the open mode protection device 100 is substantially protected by the protection unit 110 against ESD, EOS or surge such as a varistor. Function as.

On the other hand, if the protection unit 110 does not have sufficient protection against ESD, EOS or surge introduced from the outside, some of the LED load 12 is damaged by ESD, EOS or surge, the LED load 12 is open. Often it happens.

At this time, as shown in FIG. 15, all of the currents i _open of the constant current source 10 flow to the open mode protection device 100.

Accordingly, since the constant current source 10 continuously supplies a constant current, the voltage also increases greatly while the current flowing in the open mode protection device 100 increases. As a result, the protection unit 110 of the open mode protection device 100 gradually increases in temperature due to overcurrent and overvoltage.

At this time, when the temperature of the protection unit 110 rises above a certain temperature, the resistance value of the current suppressing unit 120 is greatly increased, thereby reducing the current flowing in the protection unit 110, thereby both ends of the protection unit 110. The temperature can be suppressed by reducing the voltage.

Accordingly, by suppressing abnormal overheating of the open mode protection device 100, in addition to preventing damage to circuit components adjacent to the open mode protection device 100, the adjacent parts are made of a flammable material. When white sheet paper is disposed in front of the LED to improve the efficiency of the light emitted from the fire, it is possible to prevent the fire due to the ignition of the protection element.

As shown in FIG. 16, the method 20 for manufacturing the open mode protection device according to the second embodiment of the present invention includes the steps of forming a slit on a substrate (S201), mounting the protection device (S202), and epoxy. Molding (S203), and cutting into unit devices (S205).

Here, the open mode protection device manufactured by the manufacturing method 20 includes a constant current source and a load by bypassing an ESD, EOS or surge current introduced from the outside by being connected in parallel to a load consisting of a constant current source and an LED, respectively, to ground. It is to protect the circuit.

First, as shown in FIG. 17, slits 216 are formed at a predetermined interval on a large area PPTC substrate

210a having electrodes

212 and 214 formed on both surfaces thereof (step S201).

In this case, the slit 216 may be formed at a predetermined interval corresponding to a space required to cut the large area PPTC substrate 210a into unit devices. That is, according to the cutting precision made in the cutting step S205, for example, the size of the interval for arranging the slits 216 can be determined according to the precision of the cutting mechanism.

Here, the

electrodes

212 and 214 formed on both surfaces of the large-area PPTC substrate 210a may be prepared in advance. In one example, the double-

sided electrodes

212 and 214 may be formed in advance by Ni or Cu plating. At this time, in order to improve the adhesion of the Cu surface it may be further plated by any one of Fe, Ni, Cr and Ag.

In addition, the large area PPTC substrate 210a may be formed of a PPTC material having a base layer between the

electrodes

212 and 214. In one example, the base layer may be made of a polymer layer in which the conductive filler is dispersed. In this case, the conductive filler may be made of a carbon black material.

Here, the PPTC device formed by the large area PPTC substrate 210a increases withstand thickness according to its thickness. That is, in the PPTC device, the breakdown voltage increases as the distance between the top electrode 212 and the bottom electrode 214 increases. Accordingly, in order to apply the PPTC device to a backlight (BLU) of a display device such as a TV requiring high breakdown voltage, the PPTC device needs to configure a large distance between the top electrode 212 and the bottom electrode 214. Results in an increase in the overall thickness.

Therefore, the manufacturing method 20 of the open mode protection device according to the second embodiment of the present invention has a large area such that the PPTC devices are spaced apart on the same plane in order to realize thinning without increasing the thickness of the open mode protection device. The slit 216 may be formed in the PPTC substrate 210a. That is, in the finally calculated unit element, since a pair of PPTC elements are arranged on the same plane, the increase in thickness is suppressed, and since they are arranged in series on both sides of the protection element, the two elements on the current path Since the PPTC devices are arranged in series, it is possible to increase the breakdown voltage as a result.

Next, as shown in FIG. 18, the protection device 220 for bypassing the overvoltage or the overcurrent is mounted on the upper surface electrode 212 with the slit 216 therebetween (step S202). Here, the protection element 220 may be disposed such that the slit 216 is positioned at a substantially central portion of the lower portion of the protection element 220 (see FIG. 19).

In this case, the protection device 220 may be mounted on the top electrode 212 of the large area PPTC substrate 210a through an SMT soldering process. That is, the protection device 220 may be connected to the top electrode 212 of the large area PPTC substrate 210a through solder.

Here, the protection elements 220 may be spaced apart at regular intervals to secure a space necessary for cutting the large-area PPTC substrate 210a into unit elements, similar to the intervals in which the slits 216 are disposed. That is, according to the precision of the cutting mechanism, the size of the interval for arranging the protection element 220 can be determined.

As such, by forming the slit 216 on the large-area PPTC substrate 210a and mounting the protective element 220, a mass production is possible and an interval for forming the slit 216 or an interval for arranging the protective element 220. The size of the product can be easily adjusted according to the specification, which can be flexibly handled according to various specifications.

Here, the protection device 220 may be a single component manufactured. For example, the protection device 220 may be any one of a varistor, a suppressor, a gas discharge tube (GDT), and a diode, but is not particularly limited thereto, and may bypass overvoltage or overcurrent. It may include a device.

In this way, the existing single component is mounted on a pair of large-area PPTC substrates 210a, which not only simplifies the manufacturing process but also makes it easy to design and arrange PPTC elements in accordance with existing products, thereby increasing manufacturing efficiency. Can improve.

Meanwhile, the protection device 220 may include a varistor material layer. That is, the body of the protection device 220 may be made of a varistor material.

As another example, the protective device 220 may be formed of a body 220a. Wherein the body comprises one or more of ZnO, BaTiO ₃ , and SrTiO ₃ , wherein Pr, Bi, Ni, Mn, Cr, Co, Sb, Nd, Si, Ca, La, Mg, Al, Ti Sn, Nb, and At least one of Y may be included as a dopant.

Next, molding is performed with the molding member so as to cover the upper side of the large area PPTC substrate 210a and the protection device 220 (step S203). In this case, the molding member may be made of epoxy.

For example, as shown in FIG. 20, the epoxy sheet 230a may be disposed above the large area PPTC substrate 210a on which the protection device 220 is mounted, and pressurized to the large area PPTC substrate 210a to be heat-sealed. Can be.

Through this, the molding member 230 ′ melted by heat may be molded to completely cover the upper side of the large area PPTC substrate 210a and the protection device 220 (see FIG. 21).

In this case, the slit 216, which is a space between the large area PPTC substrate 210a at the lower side of the protection device 220, may be filled with the molding member 230 ′ melted by the heat (see FIG. 22).

That is, the molding member 230 ′ melted by the heat flows from the upper side of the large area PPTC substrate 210a to the slit 216 disposed between the protection elements 220, and is disposed below the plurality of protection elements 220. It spreads through the whole slit 216 arrange | positioned. Therefore, in the unit device, the space 202 between the pair of PPTC substrates 210 may be filled by the molding member (see FIG. 25).

Through this, in the open mode protection device 200, the strength between the pair of PPTC substrates 210 spaced apart from each other by the space part 202 corresponding to the slit 216 may be compensated for.

That is, since the pair of PPTC substrates 210 are disposed to be spaced apart from each other by the slits 216, the bond strength may be weakened between the PPTC substrates 210 or between the protection elements 220. The bonding strength may be improved by filling the space 202 corresponding to the slit 216 disposed between the PPTC substrate 210 with the molding member.

Furthermore, by preventing the exposure of the protection device 220 between the pair of large area PPTC substrates 210a, the protection device 220 can be protected from external force.

Here, the epoxy sheet 230a has been described as molding the large area PPTC substrate 210a and the protection device 220 by pressing and heat fusion. However, the present invention is not limited thereto, and it can be molded by various molding members and molding methods. Put it.

Next, the molded large area PPTC substrate 210a is cut into a unit device including one protection device 220 (step S205).

As shown in FIGS. 23 and 24, the molded large area PPTC substrate 210a may be cut along a longitudinal transmission line a and a width cutting line b corresponding to the size of the unit device.

Through this, the open mode protection device 200 which is a unit device as shown in FIG. 25 may be completed.

On the other hand, the manufacturing method 20 of the open mode protection device according to the second embodiment of the present invention may further comprise the step (S204) of plating the electrode pad.

That is, after the molding step S203, the lower surface electrode 214 of the large area PPTC substrate 210a may be plated (step S204). In this case, the lower surface electrode 214 of the large area PPTC substrate 210a may be plated with any one of Ag, Pt, Sn, Cr, Al, Zn, and Au.

Through this, the flatness and electrical conductivity of the lower surface electrode 214 used as the electrode pad of the unit element can be improved, and the electrode 214 can be protected if it is not easily worn or corroded.

As described above, the open mode protection device 200 manufactured by the method 20 for manufacturing the open mode protection device of the present invention may include a PPTC substrate 210, a protection device 220, and a molding part 230.

The open mode protection device 200 is used in an electronic device having an LED as a load, for example, a backlight (BLU) of a display device such as a TV, various lamps of a vehicle, and smart lighting using dimming to protect a circuit. will be.

In this case, the open mode protection device 200 may be connected in parallel to the constant current source and the LED load, respectively. Here, the constant current source may supply a constant current to the LED load. The constant current source may be any one of a constant current power supply and a constant current driver.

In addition, the LED load may be composed of a plurality of LEDs. For example, the LED load may include a plurality of LEDs connected in series, a plurality of LEDs connected in series, a plurality of LEDs connected in series, connected in parallel, a plurality of LEDs connected in parallel, and a plurality of LEDs connected in parallel. It may be connected in series.

For example, the open mode protection device 200 may have one side connected to one side of the constant current source and the LED load, and the other side thereof to the other side of the constant current source and the LED load. Here, one side of the open mode protection device 200 may be connected to the ground terminal. That is, the ground terminal may be connected to the cathode side of the constant current source and the load, and may be connected to the common ground formed on the circuit board of the electronic device.

The PPTC substrate 210 may be formed in a pair and spaced apart from each other at a predetermined interval. Here, the upper electrode 212 of the PPTC substrate 210 is an internal electrode to be connected to the

electrodes

212 and 214 of the protection device 220, and the lower electrode 214 is connected to a constant current source and a load of the electronic device. For external electrodes.

The PPTC substrate 210 is electrically connected in series with both ends of the protection device 220 and senses the temperature or current of the protection device 220. At this time, when the load is opened by any one of the plurality of LEDs to be protected by damage, PPTC as the current or current supplied from the constant current source flows to the protection device 220 as the temperature or current of the protection device 220 increases. The substrate 210 reduces the current of the protection device 220.

The protection device 220 is connected to both ends of the

electrodes

212 and 214 on the internal electrodes 212 formed on the upper surfaces of the pair of PPTC substrates 210, respectively, thereby bypassing the overvoltage or the overcurrent. That is, the protection device 220 may pass an overvoltage or overcurrent caused by ESD, EOS, or surge introduced through one external electrode 214 to another external electrode 214 connected to the ground.

As a result, the open mode protection device 200 may protect the LED load by bypassing ESD, EOS, or surge flowing from the outside to the ground. That is, since the resistance of the PPTC substrate 210 is very small, the open mode protection device 200 functions as a protection device against ESD, EOS or surge such as a varistor by the protection device 220.

The protection device 220 bypasses the constant current of the constant current source to the ground through the external electrode 214 during the open mode operation of the load consisting of the LED.

The molding part 230 may be formed to cover the upper side of the pair of PPTC substrates 210a and the protection device 220. The molding unit 230 is to protect the pair of PPTC substrate 210a and the protection device 220, and to package in a single device.

The molding part 230 may be filled in the space 202 between the pair of PPTC substrate 210. That is, the space 202 between the pair of PPTC substrates 210 formed as the pair of PPTC substrates 210 are spaced apart may be filled with a molding member.

As shown in FIG. 26, the open mode protection device 200 may be represented by an equivalent circuit in which a protection device B such as a varistor and a PPTC device P are connected in series. In this case, the PPTC device P may be dividedly disposed at both ends of the protection device B. FIG.

That is, in the open mode protection device 200, one end of a pair of PPTC elements P is connected to a pair of external terminals, respectively, and both ends of the protection element B are connected to the other end of the pair of PPTC elements P. By being connected, a pair of PPTC elements P and one protection element P may be connected in series with respect to external terminals.

The open mode protection device 200 according to the second embodiment of the present invention configured as described above has a low resistance at a constant temperature of 80 ° C to 120 ° C. That is, the open mode protection device 200 may function as a protection device such as a varistor to protect the circuit by bypassing ESD, EOS or surge flowing into the static electricity or the load to ground.

On the other hand, when the protection device 220 does not have sufficient protection against ESD, EOS, or surges introduced from the outside, some of the LED loads are damaged by ESD, EOS, or surges, and the LED loads are often opened. Occurs.

As such, when the load made of the LED is opened by the ESD, EOS, or surge from the outside, the current and the voltage flowing to the open mode protection device 200 continuously increase, thereby overheating the protection device 220. That is, when the load is opened because the power of the load is a constant current source, all currents of a constant magnitude provided from the constant current source flow to the open mode protection device 200. In this case, the substantial load of the constant current source is the open mode protection device 200, and in this case, a constant magnitude current flows from the constant current source to the open mode protection device 200, which is a condition in which the voltage rises indefinitely.

For example, if the constant current source supplies 400 mA of current and the LED load consists of 10 LEDs, a voltage of approximately 25 to 30 V is output at both ends of the load, but if the load is open, the open mode is a substantial load. As the voltage across the protection device 200 rises to the power supply level (200 to 300V), the open mode protection device 200, in particular, the protection device 220 is overheated.

At this time, when the open mode protection device 200 is overheated to a temperature of 150 ℃ to 200 ℃, the open mode protection device 200 increases the amount of current flowing in the open mode protection device 200 by a sudden increase in the resistance of the PPTC substrate 210 By reducing, since the voltage across the protection element 220 can be reduced to decrease the temperature, heat generation can be suppressed. Accordingly, self damage due to overheating of the protection device 220 can be prevented.

In addition, by suppressing abnormal overheating of the open mode protection device 200, not only does it prevent damage to circuit components adjacent to the open mode protection device 200, but also when the adjacent parts are made of a flammable material. When white sheet paper is disposed on the front surface of the LED to improve the efficiency of the emitted light, it is possible to prevent a fire due to the ignition of the protective device.

Although the embodiments of the present invention have been described above, the spirit of the present invention is not limited to the embodiments set forth herein, and those skilled in the art who understand the spirit of the present invention, within the scope of the same idea, the addition of components, Alterations, deletions, additions, etc. may easily suggest other embodiments, but this is also within the scope of the present invention.

Claims

An open-mode protection device connected in parallel to a load consisting of a constant current source and an LED,

A protection unit connected to one side of the first lead frame and bypassing an overvoltage or an overcurrent;

A current suppressing unit having one side connected to a second lead frame and the other side connected in series with the other side of the protection unit, and reducing the current of the protection unit as the temperature or current of the protection unit increases; And

And a molding part formed to surround the protection part and the current suppressing part.
The method of claim 1,

The protection unit and the current suppressing unit is an open mode protection device coupled via a conductive adhesive layer.
The method of claim 1,

The molding part is an open mode protection device made of EMC (Epoxy Molding Compound).
The method of claim 1,

The protection unit and the current suppressing unit is an open mode protection device connected to each of the first lead frame and the second lead frame through a solder.
The method of claim 1,

A first external electrode connected to the first lead frame and formed on one side of the molding part; And

And a second external electrode connected to the second lead frame and formed on the other side of the molding part.
The method of claim 5,

One of the first external electrode and the second external electrode is connected to one side of the constant current source and the load, the other is connected to the other side of the constant current source and the load.
The method of claim 1,

The current suppressing unit is an open mode protection device made of a positive temperature coefficient (PTC) material or a polymeric positive temperature coefficient (PPTC) material.
The method of claim 1,

The protection unit is any one of a varistor, a suppressor, a gas discharge tube (GDT) and a diode.
The method of claim 1,

An open mode protection device in which the protection unit and the current suppressing unit are vertically stacked on each other.
The method of claim 1,

The current suppressing unit is an open mode protection device made of a polymer layer in which a conductive filler is dispersed.
The method of claim 10,

The conductive filler is an open mode protective device made of a carbon black material.
Constant current source;

A load consisting of LEDs driven by the constant current source;

A ground terminal connected to one side of the constant current source and the load; And

The open mode protection device according to any one of claims 1 to 13, which is connected in parallel to the constant current source and the load, respectively, and one side thereof is connected to the ground terminal.
The method of claim 12,

The constant current source is any one of a constant current driver and a constant current power supply.
An open-mode protection device connected in parallel to a load consisting of a constant current source and an LED,

A varistor having one side connected to the first lead frame;

A PPTC substrate having one side connected to a second lead frame and the other side connected in series with the other side of the varistor;

A conductive adhesive layer coupling the other side of the varistor and the other side of the PPTC substrate;

A molding part formed to surround the varistor and the PPTC substrate;

A first external electrode connected to the first lead frame and formed on one side of the molding part; And

And a second external electrode connected to the second lead frame and formed on the other side of the molding part.