Protection device including a PTC device and a thermal device

Abstract

To provide a technique in which an overcurrent protection function works even when there is no large difference in a load current of an electric apparatus between a steady operation and an abnormal operation.SOLUTION: A protection device (100) comprising a positive temperature coefficient (PTC) element (102) having two opposed major surfaces and a thermal device (105) coupled to the PTC element with an electrically conductive material, the thermal device comprising a main body (112), a first heating element coupled to a first surface (114) thereof and a second heating element coupled to a second surface (116) of the main body, the first heating element being directly coupled to a second major surface (110) of the PTC element which is opposed to a first major surface (108) of the PTC element.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates generally to protecting electrical and electronic circuits and equipment from power surges, fault circuits, short circuits, etc. More specifically, the present disclosure relates to protection devices including a positive temperature coefficient (PTC) device coupled to a thermal device. [Background technology]

[0002] Protecting electronic circuits from damage due to excessive current or heat is the primary function of many circuit protection technologies. In the past, this protection took the form of fuses or fused links. However, in many of today's applications, resettable devices such as polymer-based positive temperature coefficient (PTC) devices, ceramic PTC devices, bimetallic breakers, and thermostats are the preferred solution. These devices do not need to be replaced after a fault event and are capable of restoring the circuit to normal operating conditions after power is interrupted and / or the overcurrent condition is removed. This resettable capability can help manufacturers reduce warranty, service, and repair costs.

[0003] Motor stall protection is a concern for small motors, such as medium-power AC / DC motors used in consumer electronics. Traditional PTC devices are ineffective at stall protection because the motor stall current is only approximately three to four times the working current. As a result, traditional PTC devices trip late under the stall current, potentially causing motor damage.

[0004] It is with respect to these and other considerations that the present improvements are provided. Summary of the Invention

[0005] This Summary is provided to introduce various concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to serve as an aid in determining the scope of the claimed subject matter.

[0006] In one approach according to the present disclosure, a protective device may include a positive temperature coefficient (PTC) element including a first major surface opposite a second major surface, and a thermal device coupled to the PTC element with a conductive material. The thermal device may include a main body, a first heating element coupled to the first surface of the main body, and a second heating element coupled to the second surface of the main body, the first heating element being directly coupled to the second major surface of the PTC element.

[0007] In another approach according to the present disclosure, a positive temperature coefficient (PTC) device may include a PTC disk including a first major surface opposite a second major surface, and a thermal device coupled to the PTC disk with a conductive material. The thermal device may include a main body, a first heating element coupled to the first surface of the main body, and a second heating element coupled to the second surface of the main body, the first heating element being directly coupled to the second major surface of the PTC disk.

[0008] In yet another approach according to embodiments of the present disclosure, a fast trip positive temperature coefficient (PTC) device may include a PTC disk including a first major surface opposing a second major surface, and a thermal device coupled to the PTC disk with a conductive material. The thermal device may include a main body and a first heating element coupled to the first surface of the main body, the first heating element being disposed in a spiral configuration along the first surface of the main body. The thermal device may further include a second heating element coupled to the second surface of the main body, the first heating element being directly coupled to the second major surface of the PTC disk. [Brief explanation of the drawings]

[0009] The accompanying drawings illustrate exemplary approaches currently devised to practice the principles of the disclosed embodiments.

[0010] [Figure 1] FIG. 1 is an end view of a PTC device according to an embodiment of the present disclosure.

[0011] [Figure 2] Figures 2A, 2B, and 2C are end and first and second side views of a thermal device of a PTC device according to an embodiment of the present disclosure, respectively.

[0012]

[0013]

[0014] [Figure 3] FIG. 1 is a side view of a thermal element of a thermal device according to an embodiment of the present disclosure.

[0015] [Figure 4] FIG. 1 is an exploded view of a PTC device during assembly according to an embodiment of the present disclosure.

[0016] The drawings are not necessarily to scale. The drawings are merely representational and are not intended to depict specific elements of the present disclosure. The drawings are intended to illustrate exemplary embodiments of the present disclosure and therefore should not be considered limiting in scope. Like numbering represents like elements in the drawings. Furthermore, for clarity of illustration, certain elements may be omitted or may not be shown to scale in some of the drawings. Furthermore, for clarity, some reference numbers may be omitted in certain drawings. DETAILED DESCRIPTION OF THE INVENTION

[0017] Embodiments according to the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings. These embodiments may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the systems and methods to those skilled in the art.

[0018] As described herein, a PTC device is provided that includes a PTC disk coupled to a thermal device. The thermal device may include one or more heating elements separated by insulation. In some embodiments, the heating element may include a spiral-shaped copper element secured directly to a surface of the PTC disk with solder. During use, heat is transferred between the heating element and the PTC disk to accelerate tripping of the PTC device to a higher resistance state.

[0019] Referring now to FIG. 1 , an assembly / device (hereinafter "device") 100 according to an embodiment of the present disclosure will be described. As shown, device 100 may include a PTC disk (hereinafter "disk") 102 coupled to a thermal device 105. Disk 102 may include a body 106 having a first major surface 108 opposite a second major surface 110. Without limitation, in this embodiment, body 106 has a circular or disk-shaped shape. It is contemplated that one or both of disk 102 and thermal device 105 may have other shapes (e.g., rectangular, triangular, irregular, etc.) without departing from the scope of the present disclosure.

[0020] The thermal device 105 may include a body 112 having a first major surface 114 facing a second major surface 116. The first major surface 114 of the body 112 of the thermal device 105 may be physically and electrically coupled to the second major surface 110 of the body 106 of the disk 102. A first terminal 120 (e.g., a lead, SMD, or wire) may be connected to the second major surface 116 of the body 112 of the thermal device 105, and a second terminal 122 (e.g., a lead, SMD, or wire) may be connected to the first major surface 108 of the body 106 of the disk 102. Although not shown, each of the first and second terminals 120, 122 may be connected to the respective surfaces of the thermal device 105 and the disk 102 by solder.

[0021] In some embodiments, the body 106 of the disk 102 may include a top foil layer that provides a connection area for the second terminal 122, and a bottom foil layer for connecting with the thermal device 105. In a conventional PTC structural arrangement, a layer of PTC material may be sandwiched between the top and bottom layers.

[0022] In some embodiments, the PTC material of the body 106 of the disk 102 may include a composition of an organic polymer and a particulate conductive filler (e.g., carbon black, or a metal or conductive metal compound). Such devices are referred to herein as polymeric PTCs, or PTC resistors, PTC devices, and / or PTC elements. Generally, the resistivity of compositions used in the devices of the present disclosure exhibits a much greater increase than its minimum value.

[0023] Device 100 can be used in several different ways and can be particularly useful in circuit protection applications, where it can function as a remotely resettable device to help protect electrical components from damage caused by excessive current and / or temperature. Components that can be protected in this manner include consumer electronics components, although embodiments herein are not limited to such.

[0024] When a sufficient current flows through a PTC device, it reaches a critical or trip value at which a significantly larger portion of the heating (and voltage drop) almost always occurs in a small portion of the device's volume. To achieve improved circuit protection devices, embodiments herein combine the overcurrent protection properties of disk 102 with thermal device 105 in an effective manner that synergistically realizes the full benefits of both elements in one combined device.

[0025] 2A-2C, the thermal device 105 will be described in more detail. The thermal device 105 may include a first heating element 124 connected to a first major surface 114 of a body 112 and a second heating element 130 connected to a second major surface 116 of the body 112. The body 112 of the thermal device 105 may be made of an insulating material to sufficiently isolate the first and second heating elements 124, 130 as desired. For example, the body 112 may be a substrate made of prepreg or FR4, ceramic, or the like. The first heating element 124 may be directly connected to the second major surface 110 of the disk 102 when assembled with the disk 102.

[0026] As best shown in FIG. 2B , the first heating element 124 may have a spiral configuration. That is, the first heating element 124 may have a first end 132 and a second end 134, and the first end 132 may be formed as a center plate 136. Solder 138 may be formed on the center plate for connecting with the second major surface 110 of the disk 102. The first heating element 124 may include a series of concentric rings 140 emanating from the center plate 136 of the first end 132. The thickness or width of the second end 134 may be greater than the remainder of the first heating element 124 to accommodate a plurality of through-holes 142.

[0027] As best shown in FIG. 2C , the second heating element 130 is coupled to the second major surface 116 of the thermal device 105 and may be a substantially solid plate including a plurality of through-holes 144 formed therein. The through-holes 144 of the second heating element 130 and the through-holes 142 of the first heating element 124 may accommodate one or more components that enable connection between the first and second heating elements 124, 130. In some embodiments, the first and second heating elements 124, 130 may be made entirely or partially of a conductive material, such as copper. As mentioned above, the second terminal 120 may be secured directly to the second heating element 130.

[0028] FIG. 3 illustrates an alternative second heating element 130. As shown, the second heating element 130 may include a fusing or trace element 148 extending from a main portion 150. The trace element 148 may include a free end 154 having a through-hole 144 formed therein. Without limitation, the trace element 148 may have multiple bends or zigzags. The trace element 148 is thinner than the main portion 150 of the second heating element 130, thereby providing a controlled breakdown point. By providing the trace element 148 as part of the second heating element 130, fuses on electrical / circuit boards may be eliminated.

[0029] 4 illustrates an approach for forming device 100 according to embodiments of the present disclosure. As shown, disk 102 may be secured to thermal device 105. In some embodiments, a second major surface of disk 102 may be secured to a first major surface of thermal device 105. More specifically, the second major surface of disk 102 may be secured to a first heating element of thermal device 105, for example, by soldering. This connection allows for the transfer of heat between disk 102 and thermal device 105.

[0030] As further shown, first and second terminals 120, 122 may then be secured to device 100. More specifically, first terminal 120 may be connected to a second major surface of thermal device 105, and second terminal 122 may be connected to a first major surface of disk 102. First and second terminals 120, 122 may be connected by solder, as is well known. Although not shown, device 100 may then be embedded in a component housing made of a flexible material or a molded part, or in a coating or encapsulant such as an epoxy.

[0031] The foregoing description has been presented for purposes of illustration and description and is not intended to limit the disclosure to the form or forms disclosed herein. For example, various features of the disclosure may be grouped into one or more aspects, embodiments, or configurations for the purpose of streamlining the disclosure. However, it should be understood that various features of particular aspects, embodiments, or configurations of the disclosure may be combined into alternative aspects, embodiments, or configurations. Furthermore, the following claims are incorporated into this detailed description by this reference, with each claim standing on its own as a separate embodiment of the disclosure.

[0032] As used herein, elements or steps described in the singular and preceded by the word "a" or "an" should be understood not to exclude a plurality of elements or steps, unless such exclusion is expressly stated. Furthermore, references to "one embodiment" in the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.

[0033] When used herein, the words "including," "comprising," or "having," and variations thereof, are intended to encompass the items listed thereafter and equivalents thereof, as well as additional items. Thus, the terms "including," "comprising," or "having," and variations thereof, are open-ended and may be used interchangeably herein.

[0034] As used herein, the terms "at least one," "one or more," and "and / or" are open-ended expressions that function both conjunctively and disjunctively. For example, the phrases "at least one of A, B, and C," "at least one of A, B, or C," "one or more of A, B, and C," "one or more of A, B, or C," and "A, B, and / or C" each mean A only, B only, C only, a combination of A and B, a combination of A and C, a combination of B and C, or a combination of A, B, and C.

[0035] All directional references (e.g., proximal, distal, upper, lower, upward, downward, left, right, lateral, longitudinal, front, rear, top, bottom, above, below, vertical, horizontal, radial, axial, clockwise, and counterclockwise) are used for identification purposes only to facilitate the reader's understanding of this disclosure and do not impose limitations on the location, orientation, or use of this disclosure in particular. Connection references (e.g., attached, coupled, connected, and joined) should be interpreted broadly and, unless otherwise indicated, may include intermediate members between elements and may allow relative movement between the elements. Thus, connection references do not necessarily imply that two elements are directly connected and in a fixed relationship to each other.

[0036] Furthermore, terms of identification (e.g., primary, secondary, first, second, third, fourth, etc.) are not intended to imply importance or priority, but are used to distinguish one feature from another. The drawings are for illustrative purposes only, and the dimensions, positions, order, and relative sizes reflected in the drawings attached hereto may vary.

[0037] Additionally, the terms "substantial" or "substantially" and "approximate" or "approximately" can be used interchangeably in some embodiments and can be described using any relative measure acceptable to one of ordinary skill in the art. For example, these terms can serve as a comparison to a reference parameter to indicate a deviation that can provide an intended function. Without limitation, the deviation from the reference parameter can be, for example, less than 1%, less than 3%, less than 5%, less than 10%, less than 15%, less than 20%, etc.

[0038] The present disclosure is not limited in scope by the specific embodiments described herein. Indeed, various other embodiments of and modifications to the present disclosure, in addition to those described herein, will be apparent to those skilled in the art from the foregoing description and accompanying drawings. Accordingly, such other embodiments and modifications are intended to be included within the scope of the present disclosure. Moreover, the present disclosure has been described herein in the context of particular implementations in particular environments for particular purposes. Those skilled in the art will recognize that its utility is not limited thereto, and that the present disclosure may be beneficially implemented in a variety of environments for a variety of purposes. Accordingly, the claims set forth below should be construed in light of the full breadth and spirit of the present disclosure as described herein.

Claims

1. a positive temperature coefficient (PTC) element having a first major surface opposite a second major surface; and a thermal device coupled to said PTC element by a conductive material, wherein said thermal device is Main body; a first heating element coupled to the first surface of the main body; and a second heating element coupled to the second surface of the main body; wherein the first heating element is directly coupled to the second major surface of the PTC element. A protection device comprising:

2. a first terminal coupled to the first major surface of the PTC element; and a second terminal coupled to the second heating element; The protection device of claim 1 further comprising:

3. The protection device of claim 1 , wherein the main body of the thermal device comprises an insulating material.

4. 2. The protection device of claim 1, wherein the first heating element is coupled to the PTC element with the conductive material, the conductive material being solder.

5. The protection device of claim 1 , wherein the first heating element is arranged in a spiral configuration.

6. The protection device of claim 1 , wherein the first heating element has a free end, the free end including a plurality of through holes.

7. The protection device of claim 1 , wherein the first heating element and the second heating element are copper, silver, a NiP alloy, a NiCr alloy, or a resistive film.

8. 8. A protection device according to any one of claims 1 to 7, wherein the second heating element is a substantially solid plate containing a plurality of through holes.

9. The protection device of claim 1 , wherein the second heating element includes a fused trace, the fused trace including a plurality of through holes.

10. a positive temperature coefficient (PTC) disk having a first major surface opposite a second major surface; and a thermal device coupled to said PTC disk with a conductive material, wherein said thermal device is Main body; a first heating element coupled to the first surface of the main body; and a second heating element coupled to the second surface of the main body; wherein the first heating element is directly coupled to the second major surface of the PTC disc. A PTC device comprising:

11. a first terminal coupled to the first major surface of the PTC disc; and a second terminal coupled to the second heating element; The PTC device of claim 10 further comprising:

12. 11. The PTC device of claim 10, wherein the main body of the thermal device comprises an insulating material, and the first heating element is coupled to the PTC disk with an electrically conductive material, the electrically conductive material being solder.

13. 11. The PTC device of claim 10, wherein the first heating element is arranged in a spiral configuration, the first heating element having a free end, the free end including a plurality of through holes.

14. 11. The PTC device of claim 10, wherein the first heating element and the second heating element are copper, silver, a NiP alloy, a NiCr alloy, or a resistive film.

15. 15. The PTC device according to any one of claims 10 to 14, wherein the second heating element is a substantially solid plate containing a plurality of through holes.

16. 15. The PTC device of claim 10, wherein the second heating element includes a fused trace, the fused trace including a plurality of through holes.

17. a positive temperature coefficient (PTC) disk having a first major surface opposite a second major surface; and a thermal device coupled to said PTC disk with a conductive material, wherein said thermal device is Main body; a first heating element coupled to a first surface of the main body, wherein the first heating element is arranged in a spiral configuration along the first surface of the main body; and a second heating element coupled to the second surface of the main body; wherein the first heating element is directly coupled to the second major surface of the PTC disc. A fast trip PTC resistor comprising:

18. a first terminal coupled to the first major surface of the PTC disc; and a second terminal coupled to the second heating element; 20. The fast trip PTC resistor of claim 17, further comprising:

19. 18. The fast trip PTC resistor of claim 17, wherein the main body of the thermal device comprises an insulating material and the first heating element is directly coupled to the PTC disk with the conductive material.

20. 20. The fast trip PTC resistor of claim 17, wherein the first heating element and the second heating element are copper, silver, a NiP alloy, a NiCr alloy, or a resistive film, the second heating element has a fused trace, and the fused trace includes a plurality of through holes.

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