JP2006040798A - Circuit board and electronic equipment using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an overcurrent protecting technology convenient to use in which a pattern conductor for a fuse is used. <P>SOLUTION: As a circuit board, this is provided with a connection switching means to select either a plurality of the pattern conductors for a fuse connected mutually in parallel, and the plurality of pattern conductors for the fuse connected in series respectively to the plurality of pattern conductors for the fuse and to connect it to the circuit, and when the pattern conductor for the fuse in using is fused by the overcurrent, the other pattern conductor for the fuse out of the plurality is made into a connection state by the connection switching means, and an electric current passage or a signal passage to a load side circuit is newly formed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuse made of a patterned conductor, and more particularly to a configuration of a circuit board using the fuse.

  As conventional techniques related to the present invention, for example, Japanese Patent Application Laid-Open No. 2002-369377 (Patent Document 1), Japanese Patent Application Laid-Open No. 2000-3662 (Patent Document 2) and Japanese Patent Application Laid-Open No. 10-21817 (Patent Document 3). There is what is described in. Japanese Patent Laid-Open No. 2002-369377 is used in an apparatus to provide an electronic apparatus that suppresses an overcurrent caused by an incorrect wiring of a power source from affecting other electronic apparatuses through a signal ground line. A structure having a terminal for inputting or outputting a signal and having a fuse on a signal ground line between the terminal and the circuit is described. JP-A-2000-3662 discloses an overcurrent of an electric device using a commercial power source. In order to protect against electrical current, a commercial power supply and electrical components are connected via a wiring pattern, and when a part of the wiring pattern is made thinner than others and an overcurrent flows, the part is blown out. Japanese Patent Laid-Open No. 10-21817 discloses a configuration of such a structure, and in a resistance temperature fuse, the influence of heat generated in the circuit on the fusible metal body is reduced, and the melting setting of the fusible metal body is performed. The distance between the circuit pattern and the fusible metal body on the printed circuit board in order to ensure that the meltable metal body is melted in a certain time and the inflow of overcurrent to the circuit is cut off by stabilizing the temperature rise of the circuit board. And the circuit pattern is consumed before the heat generated by the circuit pattern is transmitted to the fusible metal body.

JP 2002-369377 A JP 2000-3662 A Japanese Patent Laid-Open No. 10-21817

  Among the above conventional techniques, the technique described in Japanese Patent Laid-Open No. 2002-369377 simply includes one pattern fuse 11 on a signal ground line and a solder land 12 for mounting a chip fuse in parallel to the pattern fuse 11. The chip fuse is attached to the solder land 12 when the pattern fuse 11 is melted by overcurrent. Further, the technique described in Japanese Patent Laid-Open No. 2000-3662 is merely a technique in which a part of the thin wiring pattern 43 of one wiring pattern 12 is provided with a fuse function, and the wiring pattern 43 is blown out. Can not form a new current path instead. Furthermore, the technique described in Japanese Patent Application Laid-Open No. 10-21817 is merely a pattern of a fusible metal body 4a as a configuration of the overcurrent interrupting portion of the resistance temperature fuse. When the molten metal body 4a is melted, it is difficult to form a new current path instead.

The problem of the present invention is that, in view of the state of the prior art described above, in a circuit board or an electronic device using the circuit board, even when the patterned conductor for fuses in the circuit board is blown by an overcurrent, the circuit board and the fuse are It is to enable a current path and a signal path to be formed by a fuse pattern conductor without replacement.
An object of the present invention is to solve such problems and provide an overcurrent protection technique suitable for mass production and easy to use using a patterned conductor for fuses.

  In order to solve the above problems, in the present invention, as a circuit board, a plurality of fuse pattern conductors connected in parallel to each other, and the plurality of fuse pattern conductors connected in series to each of the plurality of fuse pattern conductors Connection switching means for selecting any one or a part of the patterned conductors to connect to the circuit, and when the fuse patterned conductor in use is blown by overcurrent, the connection switching means causes the plurality of the plurality of patterned conductors to be connected to the circuit. The other fuse pattern conductors are connected to form a new current path or signal path to the load side.

  According to the present invention, it is possible to provide an easy-to-use overcurrent protection technique that is suitable for mass production and does not require replacement of a fuse or a circuit board.

The best mode for carrying out the present invention will be described below with reference to the drawings.
1 to 3 are explanatory views of a first embodiment of the present invention. FIG. 1 is a structural example diagram of a fuse patterned conductor provided on a circuit board as a first embodiment of the present invention, FIG. 2 is an example of a fusing characteristic of a fuse patterned conductor, and FIG. It is a structural example figure of the circuit board as an Example. The first embodiment is an example in which three fuse patterned conductor portions are provided in parallel.

  In FIG. 1, 1 is a circuit board, 100 is a fuse portion, 10 is an input-side patterned conductor portion connected to, for example, a power circuit, and 11a, 12a, 11b, 12b, 11c, and 12c each select a connection body. Connection land portions (12a, 12b and 12c are first connection land portions, 11a, 11b and 11c are second connection land portions), and 30a, 30b and 30c are fuse patterns. The conductor part, 40 is a chip resistor as a connection body, 20 is an output side patterned conductor part connected to, for example, a load side circuit, and 21a, 21b, and 21c are fuse patterned conductor parts 30a, 30b, and 30c, respectively. These are patterned conductor portions that connect the output-side patterned conductor 20. The connection land portions 11a and 12a form a first connection switching pattern conductor of the connection switching means, and the connection land portions 11b and 12b or 11c and 12c are the second connection switching of the connection switching means. A patterned conductor is formed. The fuse pattern conductor 30a forms a first fuse pattern conductor, and the fuse pattern conductor 30b or 30c forms a second fuse pattern conductor.

  In the configuration of the present embodiment, the input side patterned conductor portion 10, the connection land portions 11a, 12a, 11b, 12b, 11c, 12c (the first connection land portions 12a, 12b, 12c, the second connection land portion) 11a, 11b, 11c), the fuse patterned conductor portions 30a, 30b, 30c, the patterned conductor portions 21a, 21b, 21c, and the output side patterned conductor portion 20 are integrally formed of conductors of the same material. It is. Each of the fuse patterned conductor portions 30a, 30b, and 30c is configured to have a smaller cross-sectional area than the other portions, and is blown when an overcurrent of a predetermined value or more flows. . The fuse-patterned conductor portions 30a, 30b, 30c may be blown by an overcurrent having substantially the same cross-sectional area, or different cross-sectional areas. It may be blown by overcurrent. The larger the cross-sectional area, the larger the fusing current value.

  In the above configuration, for example, the chip resistor 40 is connected to the connection land portions 11a and 12a and the connection of the fuse pattern conductor portion 30a is turned on. The conductor portion 10, the connecting land portion 11a, the chip resistor 40, the connecting land portion 12a, the fuse patterned conductor portion 30a, the patterned conductor portion 21a, and the output side patterned conductor portion 20 form a first current path. When an overcurrent flows through the first current path at this time, the fuse patterned conductor 30a is melted and the first current path is turned off. As a result, the flow of overcurrent into the load side circuit is blocked. In order to supply a predetermined operation current from the power supply side circuit to the load side circuit again, the chip resistor 40 is removed from, for example, the connection land portions 11a and 12a and newly connected to the connection land portions 11b, 12b, or 11c. , 12c, thereby turning on the connection of the fuse patterned conductor 30b or 30c. When the chip resistor 40 is connected to the connection land portions 11b and 12b and the connection of the fuse patterned conductor portion 30b is turned on, the input side patterned conductor portion 10, the connection land portion 11b, and the chip The resistor 40, the connecting land portion 12b, the fuse patterned conductor portion 30b, the patterned conductor portion 21b, and the output side patterned conductor portion 20 form a second current path from the power supply circuit side to the load side circuit. To do. In addition, when the chip resistor 40 is connected to the connection land portions 11c and 12c and the connection of the fuse pattern conductor portion 30c is turned on, the input side pattern conductor portion 10 and the connection land portion 11c are connected. , Chip resistor 40, connection land portion 12c, fuse patterned conductor portion 30c, patterned conductor portion 21c, and output side patterned conductor portion 20 are the second current path from the power supply circuit side to the load side circuit. Form. At this time, as the chip resistor 40 connected to the connecting land portions 11b and 12b or 11c and 12c, a chip resistor different from that connected to the connecting land portions 11a and 12a may be used. In this case, it is not necessary to remove the chip resistor 40 connected to the connection land portions 11a and 12a from the land portion.

  For example, the chip resistor 40 is connected to the connection land portions 11b and 12b, the connection of the fuse patterned conductor portion 30b is turned on to form the second current path, and current is supplied to the load side circuit. Sometimes, when an overcurrent flows in the current path, the chip resistor 40 is connected to the connection land portions 11c and 12c to turn on the connection of the fuse patterned conductor portion 30c, and to open a new current path. The current is supplied to the load side circuit.

FIG. 2 is a diagram showing an example of an actual measurement result of the fusing characteristics of the fuse patterned conductor.
In FIG. 2, the horizontal axis represents the width W (unit: 10 ⁻³ m) of the fuse patterned conductor 30 and the vertical axis represents the fusing current value I (unit: A). The sample fuse pattern conductor used had a thickness t of 35 ± 5 × 10 ⁻⁶ m. As a result of actual measurement, when the width W is 0.2 × 10 ⁻³ m, the fusing current value I is about 6.8 A, and when the width W is 0.3 × 10 ⁻³ m, the fusing current value I is about 7. When the width 6 is 6A and the width W is 0.5 × 10 ⁻³ m, the fusing current value I is about 11.0 A. In the case of this sample, the fusing current value I increases as the width W increases. It was also confirmed that the fusing current value I was reproducible. As a result, the fusing current value I can be controlled with practical accuracy by increasing or decreasing the cross-sectional area of the fuse patterned conductor. The cross-sectional area of the fuse patterned conductor may be changed by the thickness t, or may be changed by the width W and the thickness t. The cross-sectional area may be narrower or wider than the cross-sectional area range of the sample.

FIG. 3 is a diagram illustrating a configuration example of the circuit board 1 as the first embodiment. The circuit board 1 is an example in which a power supply side circuit and a load side circuit are formed in a substrate shape.
In FIG. 3, 1 is a circuit board, 10 is an input side patterned conductor, 20 is an output side patterned conductor, and 100 is a fuse formed by connecting a plurality of fuse patterned conductors in parallel. In the first configuration, 200 is a power supply circuit, and 300 is a signal processing circuit as a load side circuit. In the configuration of FIG. 3, the input-side patterned conductor portion 10, the fuse portion 100, and the output-side patterned conductor portion 20 are connected between the power supply circuit 200 and the signal processing circuit 300 to form a power supply line. When an overcurrent flows from the circuit 200 side to the signal processing circuit 300 side, the overcurrent is cut off. The power supply circuit 200 and the input-side patterned conductor portion 10 may be connected by, for example, a connecting means such as a patterned conductor continuous to the input-side patterned conductor portion 10 or connected using a connector or the like. May be. The same applies to the connection between the output-side patterned conductor 20 and the signal processing circuit 300.

  According to the first embodiment of the present invention, even when an overcurrent flows in the circuit board 1 and, for example, the fuse patterned conductor portion 30a in the fuse portion 100 is melted, the chip resistance is simply reduced. By simply connecting 40 to the connecting land portions 11b, 12b or 11c, 12c, the connection of the fuse patterned conductor portion 30b or 30c can be turned on to form a new current path. For this reason, it is not necessary to replace the fuse or the circuit board even when the fuse is blown, and the usability can be improved in the circuit board and the electronic device using the circuit board, and the maintenance cost can be reduced. In addition, since the fuse is formed of a patterned conductor, it is suitable for mass production, and the cost of the circuit board and electronic equipment using the circuit board can be reduced.

FIG. 4 is an explanatory diagram of the second embodiment of the present invention. The second embodiment is an example in which the fuse unit 100 having the configuration shown in FIG. 1 is arranged in a signal line in an electronic device.
4, 400 is an electronic device A, 500 is an electronic device B, 200 ′ is a power supply circuit of the electronic device A, and 1 ′ is a circuit board of a signal processing system in the electronic device B (hereinafter referred to as a signal processing system circuit board). Reference numeral 10 denotes an input-side patterned conductor in the signal processing system circuit board 1 ′, 20 denotes an output-side patterned conductor in the signal processing system circuit board 1 ′, and 100 denotes the signal processing system circuit board 1 ′. 1 is a fuse portion formed by connecting a plurality of fuse-patterned conductors in parallel and having the same configuration as in FIG. 1, and 300 is a signal processing circuit disposed in a signal processing system circuit board 1 ′. is there. The input side patterned conductor part 10, the fuse part 100, and the output side patterned conductor part 20 form a signal line in the signal processing system circuit board 1 ′. The electronic device B500 operates normally when the signal lines and the power supply lines are connected to and from the electronic device A400.

  In the above configuration, for example, when the connection between the electronic device A400 and the electronic device B500 is mistakenly connected and the power line of the electronic device A400 is connected to the signal processing system circuit board 1 ′ of the electronic device B500 (in the case of FIG. 4) In this case, an overcurrent is supplied from the power supply circuit 200 ′ of the electronic device A400 to the signal processing system circuit board 1 ′ of the electronic device B500. As a result of the overcurrent being supplied, among the plurality of fuse-patterned conductor portions connected in parallel in the fuse portion 100, one that is turned on is blown, and the fusing causes the overcurrent signal processing. The supply to the circuit 300 is cut off, and the signal processing circuit 300 is prevented from being broken or damaged. In the fuse portion 100, for example, when the fuse patterned conductor portion 30a out of the fuse patterned conductor portions 30a, 30b, 30c connected in parallel is blown by the overcurrent, the chip resistor 40 is connected. Connected to the land portions 11b, 12b or 11c, 12c, the connection of the corresponding fuse pattern conductor 30b or 30c is turned on to form a new current path or signal path. In a state in which the connection between the electronic device A400 and the electronic device B500 is normalized, the power supply circuit 200 ′ of the electronic device A400 is connected to the power supply line of the electronic device B500, and the signal processing system circuit board 1 ′ of the electronic device B500. Is connected to the signal line of the electronic device A400, and a signal is input to the signal processing circuit 300 through the fuse patterned conductor portion 30b or 30c in which the connection is turned on by the chip resistor 40 in the fuse portion 100. Is done. Further, the electronic device B500 may be configured such that the fuse unit 100 is provided on the circuit board in the power supply line and the fuse unit 100 is provided on both the signal line and the power supply line, or the fuse unit 100 is provided only on the power supply line. The structure provided may be sufficient.

  According to the second embodiment of the present invention, in the electronic device B500, an overcurrent flows through the signal processing system circuit board 1 ′ due to erroneous connection or the like, and a plurality of parallel-connected multiple fuses 100 in the signal line are connected. Even if part of the fuse patterned conductor is blown, the connection of the other fuse patterned conductor is turned on simply by connecting an inexpensive chip resistor to the other connecting land. A new signal path can be formed. For this reason, even if a fuse in use is blown, it is not necessary to replace the fuse or the circuit board, and the usability of the circuit board and the electronic device using the circuit board can be improved and the maintenance cost can be reduced. Become. Further, since the fuse is formed of a patterned conductor, the signal processing system circuit board 1 ′ can be configured to be suitable for mass production, and the cost of the signal processing system circuit board 1 ′ and the electronic device B500 can be reduced. .

  In each of the above embodiments, the number of pattern conductors for fuses connected in parallel in the fuse unit 100 is three. However, the present invention is not limited to this, and any number may be used as long as it is plural. Further, in each of the above embodiments, one of the fuse-patterned conductor portions 30a, 30b, and 30c is in the ON state, but the present invention is not limited to this, and the fuse pattern A plurality of the conductors 30a, 30b, 30c may be turned on. The same applies when the number of fuse pattern conductors is four or more. In each of the above embodiments, the connection body connected to the connection land portion is a chip resistor. However, the present invention is not limited to this, and other means such as a conductor piece may be used.

It is a figure which shows the structural example of the patterned conductor for fuses provided in the circuit board as a 1st Example of this invention. It is a figure which shows the example of a fusing characteristic of the patterned conductor for fuses. It is a figure which shows the structural example of the circuit board as a 1st Example. It is explanatory drawing of the 2nd Example of this invention.

Explanation of symbols

1 ... Circuit board,
1 '... signal processing system circuit board,
10: Input side patterned conductor,
11a, 12a, 11b, 12b, 11c, 12c ... land for connection,
30, 30 a, 30 b, 30 c... Patterned conductor portion for fuse,
40: Chip resistance,
20 ... Output-side patterned conductor,
100 ... fuse part,
200, 200 '... power supply circuit,
300: Signal processing circuit,
400: Electronic device A,
500: Electronic device B

Claims (5)

A circuit board having a fuse portion made of a patterned conductor,
A plurality of fuse patterned conductors connected in parallel to form the fuse portion;
A connection switching means for selecting connection to the circuit of the plurality of fuse patterned conductors and turning on or any one of the plurality of fuse patterned conductors;
And a circuit board characterized in that a current or a signal is supplied to a load side through a fuse patterned conductor whose connection is turned on by the connection switching means. A circuit board having a fuse portion made of a patterned conductor,
A first fuse patterned conductor forming the fuse portion;
A first connection-switching pattern conductor that is connected in series to the first fuse pattern conductor and that turns on the connection of the first fuse pattern conductor to the circuit;
A second fuse patterned conductor connected in parallel with the first fuse patterned conductor and forming the fuse portion;
A second connection switching pattern conductor connected in series to the second fuse pattern conductor and turning on or off the connection of the second fuse pattern conductor to the circuit;
A connection body connected to the first or second connection-switching patterned conductor to turn on the connection of the first or second fuse patterned conductor to the circuit;
And a circuit board, wherein a current or a signal is supplied to a load side via the first or second fuse patterned conductor in which the connection is turned on by the connection body.   The first and second connection switching pattern conductors are respectively connected in series to the first and second fuse pattern conductors, and the first connection land portions. And a second connection land portion spaced apart in a plane, and when the connection body is connected to the first and second connection land portions, the first or second connection land portion is provided. The circuit board according to claim 2, wherein the circuit board is configured to turn on the connection of the fuse pattern conductor to the circuit.   The circuit board according to claim 2, wherein the connection body is a chip resistor. An electronic apparatus comprising the circuit board according to claim 1 for use in one or both of a power supply circuit and a signal circuit.

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