JP4967849B2 - Protective device - Google Patents

Description

  The present invention relates to a protection device mainly used for battery units of various electronic devices.

  In recent years, in portable devices such as laptop computers and video cameras, a rechargeable battery is mounted, and various operations are performed using this battery power source when carrying the device. There is a need for a device that can reliably protect electronic circuits.

  Such a conventional protection device will be described with reference to FIGS. 9 and 10. FIG.

  9 is a cross-sectional view of a conventional protective device, and FIG. 10 is an exploded perspective view. In FIG. 9, reference numeral 1 denotes a wiring board having a plurality of wiring patterns (not shown) formed on the upper and lower surfaces, 2 denotes an FET or In a switching element such as a transistor, a plurality of terminals 4 of the switching element 2 are mounted and connected to a plurality of lands 3 on the upper surface of the wiring substrate 1 by soldering, and the switching element 2 is connected to a battery (not shown) via a wiring pattern. ) Or an electronic circuit (not shown) of the device.

  Reference numeral 5 denotes a thermal fuse, and the left and right terminals 6 are soldered to the lands 7, connected between the switching element 2 and the battery, and placed on the upper surface of the wiring board 1 near the right side of the switching element 2, Between the switching element 2 and the thermal fuse 5, a heat conductive resin 8 such as silicon is applied so as to cover them, thereby forming a protection device.

  In the above configuration, when the device is carried, power is supplied from the battery to the electronic circuit through the switching element 2 to perform various operations of the device, and when the battery is charged, the switching element 2 is used. The battery is charged from a charger or the like through the switching element 2.

  In addition, when an overcurrent flows through the switching element 2 due to a short circuit or the like when operating such a device or charging a battery, the switching element 2 generates heat due to this overcurrent, This heat is transmitted to the thermal fuse 5 through the heat conductive resin 8.

  When the overcurrent flows to some extent and the heat transmitted to the thermal fuse 5 reaches a predetermined temperature or more, the thermal fuse 5 is melted and the power supply from the battery to the switching element 2 and the electronic circuit is cut off. The

  That is, the thermal fuse 5 connected between the battery and the switching element 2 detects heat generation of the switching element 2 due to overcurrent and the like, and shuts off the power supply from the battery, thereby causing damage to the device due to a short circuit or the like. It was configured to prevent.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
Japanese Patent Laid-Open No. 11-330665

  However, the above-described conventional protection device is configured to transmit this heat to the thermal fuse 5 through the heat conductive resin 8 having relatively good heat conductivity when an overcurrent flows and the switching element 2 generates heat. However, depending on the distance between the switching element 2 and the thermal fuse 5 and the conditions under which the device is used, there is a problem that the heat transfer may vary.

  The present invention solves such a conventional problem, and an object of the present invention is to provide a protection device capable of reliably protecting an electronic circuit with a simple configuration.

  In order to achieve the above object, the present invention has the following configuration.

According to the first aspect of the present invention, there is provided a wiring board having a wiring pattern formed on at least one of an upper surface and a lower surface, and a substantially rectangular parallelepiped in which a plurality of terminals are extended outwardly from both sides by switching between battery power sources. Switching element and a substantially cylindrical temperature fuse that is mounted in the vicinity of the switching element and whose terminals extend from both ends, and both terminals of the temperature fuse with respect to the direction of both sides of the terminal of the switching element. as direction is parallel, by arranging the switching element and the thermal fuse, the thermal conduction pattern disposing the thermal fuse on the circuit board is provided, both sides of the switching element the heat conduction pattern of this is extended to the lower surface is between the terminals Rutotomoni, applied to protection devices a thermally conductive resin covering them between the switching element and the temperature fuse It is obtained by configuration, with good heat conduction pattern of thermal conductivity such as copper, together with transmitting the heat generated by the switching element temperature fuse, being transmitted to the thermal fuse heating of the switching elements via a thermally conductive resin Therefore, heat can be transmitted with little variation, and thus a protective device capable of reliably protecting an electronic circuit can be obtained with a simple configuration.

According to a second aspect of the present invention, there is provided a wiring board having a wiring pattern formed on at least one of an upper surface and a lower surface, and a substantially rectangular parallelepiped switching element in which a battery power source is switched and a plurality of terminals extend outward from both sides. And a substantially cylindrical temperature fuse that is mounted in the vicinity of the switching element and has terminals extending from both ends. The direction of both terminals of the temperature fuse is relative to the direction of both side surfaces of the switching element. so as to be parallel, by arranging the switching element and the thermal fuse, the thermal conduction pattern disposing the thermal fuse on the circuit board is provided, the heat conduction pattern of this as well as connected to the terminal of the switching element It is obtained by the protective device by applying a thermally conductive resin covering them between the switching element and the temperature fuse, switching Together securely conduct heat exotherm from the terminal directly communicated thermal fuse thermally conductive pattern of the element, by heat generation of the switching element is transmitted to the thermal fuse via the heat-conductive resin, the variation is small, reliable electronic circuit It has the effect | action that the protective device which can perform protection of can be obtained.

  As described above, according to the present invention, it is possible to obtain an advantageous effect that it is possible to realize a protective device capable of reliably protecting an electronic circuit with a simple configuration.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  In addition, the same code | symbol is attached | subjected to the part of the structure same as the structure demonstrated in the term of background art, and detailed description is simplified.

(Embodiment 1)
The first aspect of the present invention will be described with reference to the first embodiment.

  FIG. 1 is a cross-sectional view of a protective device according to a first embodiment of the present invention, FIG. 2 is an exploded perspective view thereof, and 11 is a wiring board such as paper phenol or glass-filled epoxy, and is arranged on the upper and lower surfaces. A plurality of wiring patterns (not shown) are formed of copper or the like, and in addition to the plurality of lands 3 and 7, a substantially T-shaped heat conduction pattern 12 is provided on the upper surface, and the entire surface excluding these is made of polyester. And an insulating layer (not shown) such as epoxy.

  Reference numeral 2 denotes a switching element such as an FET or a transistor. A plurality of terminals 4 are mounted and connected to a plurality of lands 3 on the upper surface of the wiring board 11 by soldering, and the switching element 2 is connected to a battery (not shown) via a wiring pattern. Or an electronic circuit (not shown) of the device.

  Reference numeral 5 denotes a temperature fuse in which a fusible metal is built in a cylinder such as a substantially cylindrical ceramic. The left and right terminals 6 are soldered to the lands 7 and connected between the switching element 2 and the battery. The thermal fuse 5 is placed on the heat transfer portion 12A of the heat conduction pattern 12 on the upper surface of the wiring board 11 and is arranged near the right side of the switching element 2.

  Further, a thermal conductive resin 8 such as silicon is applied between the switching element 2 and the thermal fuse 5 so as to cover them, and a heat collecting portion of the thermal conductive pattern 12 is provided on the lower surface of the switching element 2. 12B is extended and the protective device is comprised.

  In the above configuration, when the device is carried, power is supplied from the battery to the electronic circuit through the switching element 2 to perform various operations of the device, and when the battery is charged, the switching element 2 is used. The battery is charged from a charger or the like through the switching element 2.

  Note that, when an overcurrent flows through the switching element 2 due to a short circuit or the like when the device is operated or the battery is charged, the switching element 2 generates heat due to the overcurrent. This heat is transferred to the thermal fuse 5 through the heat conductive resin 8.

  At the same time, in the present embodiment, the heat generated by the switching element 2 is transferred from the heat collecting part 12B of the heat conduction pattern 12 extending to the lower surface of the switching element 2 to the temperature fuse 5 via the heat transfer part 12A. It is transmitted.

  For example, when an overcurrent of 5 A or more flows and the heat transmitted to the thermal fuse 5 becomes, for example, 135 ° C. or higher, the thermal fuse 5 is blown, and the power source from the battery to the switching element 2 and the electronic circuit Supply is cut off.

  That is, when an overcurrent flows and the switching element 2 generates heat, this heat is transferred to the thermal fuse 5 through the thermal conductive resin 8 and at the same time, from the thermal conductive pattern 12 having good thermal conductivity such as copper. 5, the thermal fuse 5 is surely blown at a predetermined temperature.

  That is, even when there is some variation in the distance between the switching element 2 and the thermal fuse 5 and the conditions under which the device is used, the heat conduction pattern 12 extending to the lower surface of the switching element 2 ensures the heat generation of the switching element 2. In order to prevent damage to the device due to a short circuit or the like, the temperature fuse 5 is transmitted to the battery 5 and the power supply from the battery is reliably cut off.

  As described above, according to the present embodiment, the thermal conductive pattern 12 on which the thermal fuse 5 is placed is provided on the wiring board 11, and the thermal conductive pattern 12 is extended to the lower surface of the switching element 2, whereby the switching element 2. Heat can be transmitted to the thermal fuse 5 from the heat conduction pattern 12 having good thermal conductivity such as copper, so that it is possible to obtain a protection device capable of reliably protecting an electronic circuit with a simple configuration. It is.

  Further, as shown in the exploded perspective view of FIG. 3, the central portion of the heat transfer portion 12A of the heat conduction pattern 12 is hollowed out, and a holding portion 12C in which the upper surface of the wiring board 11 is exposed and recessed is provided. If 5 is mounted, the thermal fuse 5 is held at a predetermined position, and the terminal 6 can be soldered to the land 7 without any play or misalignment, so that the device can be easily manufactured. .

(Embodiment 2)
A second embodiment of the present invention, particularly the invention according to claim 2 will be described.

  In addition, the same code | symbol is attached | subjected to the part of the structure same as the structure of Embodiment 1, and detailed description is abbreviate | omitted.

  FIG. 4 is an exploded perspective view of the protective device according to the second embodiment of the present invention. In FIG. 4, a plurality of lands 3 and 7 are provided on the upper surface of the wiring board 11 and a plurality of switching elements 2 are provided. The terminal 4 is mounted and connected to the land 3, and the switching element 2 is connected to the electronic circuit of the battery or device via the wiring pattern of the wiring substrate 11, as in the case of the first embodiment. .

  Further, the heat conductive pattern 13 is provided on the upper surface of the wiring board 11 as in the case of the first embodiment, but both ends of the heat conductive pattern 13 are connected to the lands 3A and 3B, as shown in FIG. As shown in the circuit diagram, the switching elements 2 are connected to the terminals 4A and 4B of the two FETs.

  Further, a thermal fuse 5 is placed on the heat conduction pattern 13 and is disposed near the right side of the switching element 2, and between the switching element 2 and the thermal fuse 5, the same as in the case of the first embodiment. In addition, a heat conductive resin 8 (not shown) such as silicon is applied so as to cover these, thereby forming a protective device.

  In the above configuration, when the device is carried, power is supplied from the battery to the electronic circuit via the switching element 2, and when charging the battery, the switching element 2 is switched and the battery is charged from a charger or the like. When an overcurrent flows through the switching element 2 during operation of such a device or when charging a battery, the switching element 2 generates heat, and this heat causes the heat conductive resin 8 to flow. It is transmitted to the thermal fuse 5 through the same way as in the first embodiment.

  However, in the present embodiment, the heat generated by the switching element 2 is directly transmitted from the lands 3A and 3B connected to the terminals 4A and 4B to the thermal fuse 5 through the heat conduction pattern 13, for example, an excess of 5A or more. When the current flows and the heat transmitted to the thermal fuse 5 exceeds a predetermined temperature, the thermal fuse 5 is melted and the power supply from the battery to the switching element 2 and the electronic circuit is cut off. ing.

  That is, when an overcurrent flows and the switching element 2 generates heat, this heat is transferred to the thermal fuse 5 via the heat conductive resin 8 and at the same time, this heat is transferred from the terminals 4A and 4B of the switching element 2 to the heat conduction pattern 13. By directly transmitting and transferring heat to the thermal fuse 5 reliably, the power supply from the battery is surely cut off, and damage to the device due to a short circuit or the like is prevented.

  As described above, according to the present embodiment, the thermal conductive pattern 13 on which the thermal fuse 5 is placed is provided on the wiring board 11, and the thermal conductive pattern 13 is connected to the terminals 4 </ b> A and 4 </ b> B of the switching element 2. Since the heat generated by the switching element 2 can be directly transmitted from the terminals 4A and 4B to the heat conduction pattern 13 and the heat can be reliably conducted to the temperature fuse 5, there is little variation and the electronic circuit can be reliably protected. A protective device can be obtained.

  In the above description, the configuration in which both ends of the heat conduction pattern 13 are connected to the terminals 4A and 4B of the switching element 2 incorporating two FETs has been described. The present invention can also be implemented in various configurations of switching elements such as one FET that switches the connection of two diodes, or one that connects two individual FETs.

  Further, as shown in the exploded perspective view of FIG. 6, the central portion of the heat conductive pattern 13 is hollowed out to provide a holding portion 13C in which the upper surface of the wiring board 11 is exposed and recessed, and the thermal fuse 5 is placed on the holding portion 13C. For example, the temperature fuse 5 is held at a predetermined position, and the terminal 6 can be soldered to the land 7 in a state where there is no backlash or misalignment, so that the device can be easily manufactured.

  Further, as shown in the exploded perspective view of FIG. 7, when the switching element 2 is mounted on the wiring board 11 and soldered, a pair of solder layers 13D are simultaneously formed on the upper surface of the heat conduction pattern 13, and the space between the solder layers 13D. Since the temperature fuse 5 can be held at a high location by holding the temperature fuse 5, the temperature fuse 5 can be held more reliably.

  Then, as shown in the exploded perspective view of FIG. 8, by providing the heat conduction pattern 13 with the heat collecting portion 13B extending to the lower surface of the switching element 2, in addition to the heat conduction from the terminals 4A and 4B, Since heat generation can be transmitted also from the heat collecting part 13B to the thermal fuse 5, heat can be more reliably conducted to the thermal fuse 5, and the electronic circuit can be more reliably protected.

  The protection device according to the present invention has a simple configuration and can reliably protect an electronic circuit, and is useful for battery units of various electronic devices.

Sectional drawing of the protection apparatus by the 1st Embodiment of this invention Exploded perspective view Exploded perspective view according to another embodiment The disassembled perspective view of the protection apparatus by the 2nd Embodiment of this invention Same circuit diagram Exploded perspective view according to another embodiment Exploded perspective view according to another embodiment Exploded perspective view according to another embodiment Cross-sectional view of a conventional protection device Exploded perspective view

Explanation of symbols

2 Switching element 3, 3A, 3B, 7 Land 4, 4A, 4B, 6 Terminal 5 Thermal fuse 8 Thermal conductive resin 11 Wiring board 12, 13 Thermal conduction pattern 12A Heat transfer part 12B, 13B Heat collection part 12C, 13C Holding Part 13D Solder layer

Claims (2)

A wiring board upper or lower surface of at least one wiring pattern is formed, a substantially rectangular parallelepiped switching element in which a plurality of terminals from both sides have line switching of the battery power is extended outwardly, mounted on the vicinity of the switching element It is made substantially cylindrical thermal fuse terminals extending from both side ends, as to the direction of both side surfaces terminals extending of the switching element the direction of the both terminals of the temperature fuse to be parallel, the switching by arranging the element and the thermal fuse, the thermal conduction pattern disposing the thermal fuse on the circuit board is provided, Ru the heat conduction pattern is extended to the lower surface is between terminals of both sides of the switching element A protective device in which a thermally conductive resin is applied between the switching element and the thermal fuse . A wiring board upper or lower surface of at least one wiring pattern is formed, a substantially rectangular parallelepiped switching element in which a plurality of terminals from both sides have line switching of the battery power is extended outwardly, mounted on the vicinity of the switching element It is made substantially cylindrical thermal fuse terminals extending from both side ends, as to the direction of both side surfaces terminals extending of the switching element the direction of the both terminals of the temperature fuse to be parallel, the switching An element and the thermal fuse are arranged, a thermal conduction pattern for placing the thermal fuse is provided on the wiring board, the thermal conduction pattern is connected to a terminal of the switching element, and the switching element and the thermal fuse A protective device with a thermally conductive resin applied between them .

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