JP6831177B2 - How to determine deterioration of electronic circuits, electronic devices, and lightning surge protection elements - Google Patents

Description

The present invention relates to a method for determining deterioration of an electronic circuit, an electronic device, and a lightning surge protection element.

When using Internet services, Internet service providers rent out communication devices such as modems, home gateways, and VoIP (Voice over Internet Protocol) adapters (adapter) to users. Since these communication devices are connected to outdoor lines, they are susceptible to lightning surges.

Therefore, the communication device implements lightning surge countermeasures for the communication line by using a lightning surge protection element such as a varistor. However, every time the communication device receives a lightning surge, the lightning surge protection element deteriorates and eventually loses the protection function against the lightning surge, leading to a failure of the communication device.

However, there is a problem that users of communication devices and Internet connection companies do not notice even if the lightning surge protection element is deteriorated if the communication device is operating normally. Therefore, when the communication device is returned from the user, the Internet connection operator will lend it to the next user without replacing the protection element even if the lightning surge protection element is deteriorated. ..

Then, when a communication device whose lightning surge protection element has already deteriorated is lent to a new user and the communication device is damaged by the lightning surge, the lightning surge protection element immediately stops functioning and the communication device breaks down. There was a problem that it would end up. In this case, since the new user immediately broke down the rented communication device, the user might have a bad impression on the renting business operator.

Therefore, if the Internet communication carrier can determine the degree of deterioration of the lightning surge protection element of the communication device, it is possible to eliminate the deteriorated communication device of the lightning surge protection element and re-rent it.

The electronic devices shown in Patent Document 1 and Patent Document 2 are provided with a circuit for detecting the surge waveform, surge current value, etc. received by the lightning surge protection element, and are based on the surge detection result and the characteristics of the lightning surge protection element. , The life of the lightning surge protection element is judged.

Further, in the electronic device shown in Patent Document 3, a special circuit for detecting a surge current is formed in a pattern of a printed circuit board and processed by another electronic circuit to detect the degree of deterioration of the lightning surge protection element. ..

Further, in paragraph [0020] of Patent Document 4 and FIG. 3, a circuit for grasping the history of overvoltage is shown by connecting a Zener diode having a different Zener voltage in series to a fuse having the same fusing current and arranging a plurality of them in series. There is.

Japanese Unexamined Patent Publication No. 2004-273362 Japanese Unexamined Patent Publication No. 2014-228298 Japanese Unexamined Patent Publication No. 2009-222663 Japanese Unexamined Patent Publication No. 2007-53876

However, the electronic devices shown in Patent Document 1, Patent Document 2, and Patent Document 3 have a complicated circuit configuration in order to realize a determination circuit for detecting a lightning surge and a circuit for storing a history. As a result, the electronic devices shown in these patent documents are expensive.

Further, in the circuit shown in FIG. 3 of Patent Document 4, since the element that bypasses the surge current is a Zener diode instead of the SPD, even if it can cope with a low voltage surge, it can cope with a high voltage such as a lightning surge. It is considered that there is no corresponding element. If there is a Zener diode that can withstand the voltage of a lightning surge and the circuit shown in FIG. 3 of Patent Document 4 is inserted between the output end of the SPD and the FG, the maximum value of the overvoltage can be grasped. However, it is not possible to grasp the history corresponding to the number of overvoltages. Therefore, it is not always appropriate to use the circuit shown in FIG. 3 of Patent Document 4 for determining the degree of deterioration of SPD.

An object of the electronic circuit and electronic device of the present invention is to make it possible to determine the degree of deterioration of a lightning surge protection element with a simple configuration.

In order to achieve the above object, the electronic circuit of the present invention has an electric current between a lightning surge protection element having an input terminal connected to a first terminal and an output end of the lightning surge protection element and a second terminal. It includes an element array in which a plurality of fusing elements having different physical properties are connected in parallel, and the first fusing element in the element arrangement has a predetermined upper limit surge current value which is equal to or less than the discharge withstand capacity of the lightning surge protection element. As for the second fusing element in the element arrangement, only the second fusing element is blown at a predetermined lower limit surge current value flowing through the element arrangement.

In order to achieve the above object, the electronic device of the present invention has an electric current between a lightning surge protection element having an input terminal connected to a first terminal and an output end of the lightning surge protection element and a second terminal. A plurality of fusing elements having different physical properties are provided in parallel, and the first fusing element in the element arrangement has a predetermined upper limit surge current value which is equal to or less than the discharge withstand capacity of the lightning surge protection element. The second fusing element in the element arrangement is a first electronic circuit in which only the second fusing element is blown at a predetermined lower limit surge current value flowing through the element arrangement, and the first electron. A second electronic circuit connected to the first terminal of the circuit and the second terminal is further provided.

In order to achieve the above object, the method for determining deterioration of the lightning surge protection element of the present invention includes a lightning surge protection element having an input end connected to a first terminal, an output end of the lightning surge protection element, and a second. In an electronic circuit including an element array in which a plurality of fusing elements having different electrical properties are connected in parallel between the terminals of the element arrangement, the first fusing element in the element arrangement is the discharge withstand capability of the lightning surge protection element. The second fusing element in the element arrangement is fused at a predetermined upper limit surge current value below, and only the second fusing element is fused at a predetermined lower limit surge current value flowing through the element arrangement. Deterioration of the lightning surge protection element is determined based on the fusing status of a plurality of fusing elements.

According to the electronic circuit and the electronic device of the present invention, it is possible to determine the degree of deterioration of the lightning surge protection element with a simple configuration.

It is a figure which shows the structural example of the 1st Embodiment. It is a figure which shows the operation of the 1st Embodiment. It is a figure which shows the operation of the 1st Embodiment. It is a figure which shows the structural example of the 2nd Embodiment. It is a figure which shows the operation of the 2nd Embodiment. It is a figure which shows the operation of the 2nd Embodiment. It is a figure which shows the operation of the 2nd Embodiment. It is a figure which shows the modification of 1st Embodiment. It is a figure which shows the structural example of the 3rd Embodiment.

[First Embodiment]
Next, the first embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3.
[Description of configuration]
FIG. 1 shows the configuration of the first embodiment.

The electronic device 10 is composed of an SPD (Surge Protective Device; lightning surge protective element, surge protective device, lightning arrester) 21, a communication circuit 22, and a plurality of fuse resistors 31 to 3n. Further, the electronic device 10 has a communication terminal 11 connected to a communication line and an FG (frame ground) 12.

The SPD 21 is a metal oxide varistor or the like, and is a component that bypasses a surge current by short-circuiting when a high potential difference occurs between both terminals of the component.

The communication circuit 22 is an electronic circuit for communication.

The fuse resistors 31 to 3n are resistors having a fusing characteristic, and are components that break when a current exceeding the fusing power flows. In the present embodiment, the fuse resistors 31 to 3n have different resistance values, but have the same rated power.

The communication line terminal 11 and the FG 12 are connected to the communication circuit 22. One terminal of the SPD 21 is connected to the communication line terminal 21, and the opposite terminal of the SPD 21 is connected to all the terminals of the fuse resistors 31 to 3n on one side. Further, the fuse resistors 31 to 3n are connected in parallel, and the terminal on the side not connected to the SPD 21 is connected to the FG12.

Further, the fuse resistors 31 to 3n have the same rated power. Then, it is assumed that the fuse resistors 31 to 3n are arranged so that the resistance values increase in order from the fuse resistance 31 such that the fuse resistors 31 to 3n are 10 ohms, the fuse resistance 32 is 100 ohms, and the fuse resistance 33 is 200 ohms. Details of the method for selecting the fuse resistors 31 to 3n are shown in the section of operation description.
[Explanation of operation]
Next, the operation of this embodiment will be described with reference to FIGS. 2 and 3.
(Outline of operation)
FIG. 2 schematically shows a case where a lightning surge invades from the communication line terminal 11 of the electronic device 10. When a lightning surge enters from the communication line terminal 11, a large potential difference occurs between the communication line terminal 11 and the FG 12. As a result, when the potential difference between the communication 11 side terminal and the fuse resistance side terminal of the SPD 21 exceeds the limit voltage (also referred to as voltage protection level) of the SPD 21, the SPD 21 bypasses the surge current from the communication line terminal 11 to the fuse resistance side. Then, the bypassed surge current flows to the FG 12 via the fuse resistors 31 to 3n connected in parallel.

The SPD defines a maximum current value that can bypass a surge current called discharge withstand. If a current exceeding the discharge capacity flows through the SPD, the SPD will be damaged. The surge current at which the SPD bypasses the surge current and the surge current disappears and can be restored is a current equal to or less than the discharge withstand capacity.

The electronic device 10 of the present invention records the number of times the surge current in the region where the SPD 21 is not destroyed passes through the SPD 21 as a history by sequentially blowing one or a plurality of fuse resistors 31 to 3n. Is.

Since the electronic device 10 of the present invention can determine the deterioration state of the SPD 21 based on the blown state of the fuse resistors 31 to 3n, it is usually necessary to open the case of the electronic device 10 and check the internal circuit of the SPD 21. The deterioration status cannot be determined.

However, when an Internet connection company or the like re-rents an electronic device such as a modem to a new user, the internal circuit board is often reused and the case is replaced with a new one. In this case, since the case of the electronic device returned from the previous user is opened, it is possible to check the blown status of the fuse resistor.

In addition, even if the case is not replaced when the electronic device is reused, the fuse resistance can be blown by attaching an openable lid to a part of the case so that the fuse resistance part of the internal circuit board can be confirmed. The situation can be confirmed.
(How to determine the resistance value of the fuse resistor)
Next, a method for determining the resistance value of the fuse resistors 31 to 3n will be shown.

First, determine the upper limit Imax and lower limit Imin of the surge current value that should be left as a history. Imax is a value equal to or less than the discharge withstand capacity of SPD21.

The fuse resistors 31 to 3n have the same rated power but different resistance values. In general, the power Pcut that the fuse resistor blows is proportional to the rated power. Since the rated powers of the fuse resistors 31 to 3n are the same, the Pcut value of each fuse resistor is the same.

Since the fuse resistors 31 to 3n are connected in parallel, the voltage across each fuse resistor is the same. The value obtained by dividing the square of the voltage by the resistance value is the power consumed by each fuse resistor, and the voltage across each fuse resistor connected in parallel is the same, so the lower the resistance value of the fuse resistor, the higher the power consumption. large. Therefore, among the fuse resistors connected in parallel, the fuse resistor having a lower resistance value reaches the power value Pcut at which the fuse resistor blows at a lower voltage. Therefore, a resistor having a low resistance value blows at a lower voltage than a resistor having a high resistance value, and a resistor having a high resistance value blows at a higher voltage than a resistor having a low resistance value.

Therefore, a method for determining the resistance value R3n of the fuse resistor 3n, which is the maximum resistance value among the fuse resistors 31 to 3n, will be described.

The fuse resistor 3n is determined to be blown as the last one at the upper limit surge current value Imax described above. It may be determined so that the resistance value R3n satisfies the following equation by using the power Pcut at which the fuse resistor blows and the upper limit surge current value Imax.

R3n ＝ Pcut ／ (Imax ^ 2)
Here, Imax ^ 2 represents the square of Imax.

In this way, the value of the resistance value R3n of the fuse resistor 3n, which is the maximum resistance value among the fuse resistors 31 to 3n, is determined.

Next, a method of determining the resistance value of the fuse resistors 31 to 3 (n-1) will be described. Here, the fuse resistance 3 (n-1) indicates a fuse resistance having a resistance value one before the fuse resistance 3n having the maximum resistance value, in which the resistance value increases in order from the fuse resistance 31. The resistance values of the fuse resistor 32 to the fuse resistor 3 (n-1) are expressed by a constant multiple of R31.

First, the resistance value R31 of the fuse resistor 31, which is the minimum resistance value among the fuse resistors 31 to 3n, is determined.

The resistance value R of the combined resistance of the fuse resistors 31 to 3n is the variable R31 of the fuse resistor 31, each resistance value of the fuse resistor 32 to the fuse resistor 3 (n-1) represented by a constant multiple of the variable R31, and first. It is represented by R3n for which the value was calculated. Therefore, the resistance value R of the combined resistance is represented by the variable R31.

Therefore, when a surge current value Imin, which is the lower limit determined above, is passed through the combined resistance of the resistance value R, the voltage generated across the fuse resistors 31 to 3n is defined as V. Since the power consumption of the fuse resistor 31 is obtained by dividing the square of V by the resistance value R31 of the fuse resistor 31, the power consumption of the fuse resistor 31 is represented by the variable R31.

Then, the power consumption of the fuse resistor 31 represented by the variable R31 is set to be equal to the numerical value of the power Pcut that blows the fuse resistor, and by solving the variable R31, R31 can be obtained as a numerical value.

In this way, the resistance value R31 of the fuse resistor 31, which is the minimum resistance value among the fuse resistors 31 to 3n, is determined.

Further, the resistance values of the fuse resistance 32 to the fuse resistance 3 (n-1) can be obtained as a constant multiple of R31.

As described above, the resistance value of the fuse resistors 31 to 3n is determined.
(How to determine the resistance value when there are 4 fuse resistors)
The method of setting the resistance value of the fuse resistor described above will be described in the case of four fuse resistors.

The upper limit of surge current is Imax and the lower limit of surge current is Imin.

There are four fuse resistors connected in parallel with different resistance values, and their respective resistance values are R1, R2, R3, and R4. Then, there is a relationship of R1 <R2 <R3 <R4, and R2 = a × R1, R3 = b × R1, where a and b are constants larger than 1.

Also, let Pcut be the power that blows the fuse resistor.

First, the value of R4 is determined by the following equation.

Pcut ＝ (Imax ^ 2) × R4
Next, the combined resistance R of the resistors connected in parallel is calculated by the following equation.

R = (R1, R2, R3, R4) / (R2, R3, R4 + R1, R3, R4 + R1, R2, R4 + R1, R2, R3)
Here, since R2 = a × R1 and R3 = b × R1, R is represented by one variable R1.

Therefore, when Imin flows through the combined resistor R, the voltage V across the combined resistor R is expressed by the following equation.

V = Imin × R
Here, Imin is a predetermined value, and R is represented by one variable R1 as described above, so V is also represented by one variable R1.

Next, the power consumption P1 of R1 having the smallest resistance value is expressed by the following equation.

P1 ＝ (V ^ 2) ／ R1
Here, since both V and R can be represented by one variable R1, P1 can also be represented by one variable R1.

Then, by setting P1 = Pcut and solving for R1, the resistance value of the fuse resistor R1 can be obtained as a numerical value.

R2 is obtained by R2 = a × R1, and R3 is obtained by R3 = b × R1.

When the values of the fuse resistors R1 to R4 are determined as described above, the fuse resistor R1 with the smallest resistance value blows with the smallest current among the four fuse resistors connected in parallel, and the resistance is the highest. The fuse resistor R4 with a large value blows at the largest current. The above method for determining the resistance value of the fuse resistor shows the idea, and since the surge current is a transient phenomenon, the blowing power and resistance value are It is necessary to confirm it appropriately by experiments.

The surge current at which the fuse resistor blows takes a value between Imin and Imax, and the fuse resistor does not always blow one by one each time a lightning surge enters, but the resistor with the smallest resistance value. Fuse in order from.
(Details of operation)
The details of the operation when the electronic device 10 in which the resistance values of the fuse resistors 31 to 3n are set as described above are subjected to a lightning surge are shown step by step.

In FIG. 2, the flow of surge current when the electronic device 10 first receives a lightning surge is schematically shown by a dotted arrow.

In FIG. 2, when a lightning surge invades the communication line terminal 11, the SPD 21 operates and the communication circuit 22 is protected. However, since the SPD21 operated due to a lightning surge, the component performance deteriorated. When the surge current flows through the fuse resistors 31 to 3n connected in parallel, the largest current flows through the fuse resistor 31, which is the lowest resistance value among the fuse resistors connected in parallel. Therefore, among the fuse resistors connected in parallel, the fuse resistor 31 reaches the blowing power first, and the fuse resistor 31 blows first. It can be known that the SPD 21 has deteriorated due to the lightning surge caused by the blown fuse resistor 31.

Next, FIG. 3 schematically shows a case where a lightning surge enters the electronic device 10 from the communication line terminal 11 again.

In FIG. 3, when a lightning surge enters from the communication line terminal 11, the SPD 21 operates and the communication circuit 22 is protected. However, since the SPD21 operated due to a lightning surge, the component performance was further deteriorated. Further, when the surge current flows through the fuse resistors 32 to 3n connected in parallel, the largest current flows through the fuse resistor 32, which is the lowest resistance value among the fuse resistors connected in parallel. Therefore, among the fuse resistors connected in parallel, the fuse resistor 32 reaches the blowing power first, and the fuse resistor 32 blows first.

Then, it can be known that the blown fuse resistor 32 causes the SPD 21 to operate due to a lightning surge and further deteriorates from the state in which the fuse resistor 31 is blown.

In this way, each time a lightning surge invades the electronic device 10, the fuse resistor is sequentially blown.

As described above, the fuse resistors are not always blown one by one with one surge current. However, if a plurality of fuse resistors are blown by one surge current, a surge current larger than the surge current that one fuse resistor blows flows through the SPD 21. Therefore, the SPD 21 is more deteriorated when a plurality of fuse resistors are blown than when one fuse resistor is blown, which is more suitable for the original purpose of knowing the degree of deterioration of the SPD 21.

Further, each time the fuse resistor 32 is blown, the surge current for blowing is gradually increased, but the number of blown fuse resistors is the deterioration of SPD due to a lightning surge having a current value between Imin and Imax. It is a rough guide for.

Each time a lightning surge enters the communication line terminal, the fuse resistors 31 to 3n are blown in ascending order of resistance value. Finally, the fuse resistor 3n is blown, and the SPD 21 is disconnected from the electronic circuit of the electronic device 10.

As described above, according to the electronic device 10 shown in the present embodiment, it is possible to determine the degree of deterioration of the SPD 21 with a simple configuration of only the fuse resistor.
[Second Embodiment]
Next, the second embodiment will be described with reference to FIGS. 4 to 7.
[Description of configuration]
FIG. 4 shows the configuration of the second embodiment.

In the electronic device 10 of the first embodiment, the SPD 21 and the fuse resistors 31 to 3n are inserted between the communication line terminal 11 and the FG 12.

In the electronic device 50 of the present embodiment, the SPD 21 inserted between the communication line terminal 11 connected to the communication circuit 22 and the FG 12 and the fuse resistors 31 to 3n have the same configuration. However, in the electronic device 50, the SPD 23 and the fuse resistors 41 to 4n are inserted between the AC power supply terminal 13 of the communication circuit 22 and the FG 12 common to the communication line terminal.

The number of communication lines and AC power lines may be plurality, and FIG. 4 shows one of them.

Further, the method of setting the resistance values of the fuse resistors 31 to 3n and the fuse resistors 41 to 4n is the same as the description of the first embodiment. However, since the voltage and current handled in the normal time when no surge occurs are different between the communication line terminal 11 and the AC power supply terminal 13, the specifications of the surge current at which the SPD operates differs between the communication line terminal and the AC power supply terminal. Therefore, since the upper and lower limits of the surge current are set differently, the resistance values of the fuse resistors 31 to 4n and the resistance values of the fuse resistors 41 to 4n are different.
[Explanation of operation]
Next, the operation of this embodiment will be described with reference to FIGS. 5 to 7.

First, a case where a lightning surge invades the communication line terminal 11 will be described. In FIG. 5, the dotted arrow schematically shows the flow of surge current when the communication line terminal 11 is first subjected to a lightning surge. The operation when a lightning surge enters the communication line terminal 11 is the same as the operation of the first embodiment, and thus the description thereof will be omitted.

In this way, when a lightning surge invades the communication line terminal 11, one or more of the fuse resistors 31 to 3n are blown, but the surge current does not flow through the fuse elements 41 to 4n, so that the fuse elements 41 to 41 4n is not blown.

Next, a case where a lightning surge invades the AC power supply terminal 13 will be described. In FIG. 6, the dotted arrow schematically shows the flow of the surge current when the AC power supply terminal 13 is first subjected to a lightning surge. The operation of blowing the fuse resistors 41 to 4n is the same as the operation of blowing the fuse resistors 31 to 4n of the first embodiment, and thus the description thereof will be omitted.

In this case, one or more of the fuse resistors 41 to 4n are blown, but since the surge current does not flow through the fuse elements 31 to 4n, the fuse elements 41 to 4n are not blown.

Therefore, by confirming whether the fuse resistors 31 to 3n are blown or the fuse resistors 41 to 4n are blown, it is confirmed whether the lightning surge intrusion path into the electronic device 50 is a communication line or an AC power supply. It is possible.

For example, if the fuse resistor 41 and the fuse resistor 42 were blown as shown in FIG. 7, it was found that a lightning surge had invaded the electronic device 50 from the AC power supply, and no lightning surge had invaded from the communication line. You can see that. Knowing the intrusion route of lightning surges makes it easier to take preventive measures against lightning surges.

As described above, in the electronic device 50 shown in the present embodiment, in addition to being able to determine the degree of deterioration of the SPD 21 and SPD 23 with a simple configuration of only the fuse resistor, it is possible to confirm the intrusion route of the lightning surge.
[Third Embodiment]
Next, the third embodiment will be described with reference to FIG.

The electronic device 100 of the present embodiment has an electrical property between the lightning surge protection element 111 whose input end is connected to the first terminal 101 and the output end of the lightning surge protection element 111 and the second terminal 102. It includes an element arrangement in which different fusing elements 112 and fusing elements 113 are connected in parallel. Then, the first fusing element 112 in the element arrangement is fusing at a predetermined upper limit surge current value which is equal to or less than the discharge withstand capacity of the lightning surge protection element 111. Further, in the second fusing element 113 in the element arrangement, only the second fusing element 113 is fused at a predetermined lower limit surge current value flowing through the element arrangement.

As described above, according to the electronic device 100 shown in the present embodiment, it is possible to determine the degree of deterioration of the lightning surge protection element 111 with a simple configuration of only the fusing element 112 and the fusing element 113.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and can be extended or modified as follows.

The communication circuit shown in the first and second embodiments may be an electronic circuit other than the communication circuit.

Next, the configuration of the modified example of the first embodiment is shown in FIG.

In FIG. 8, the communication path by the combination of the communication line 1 and FG connected to the communication line terminal 1 (reference numeral 61) and the communication path by the combination of the communication line 2 and FG connected to the communication line terminal 2 (reference numeral 62). Two communication paths are formed. In the case of an electronic device having a plurality of communication lines in this way, the surge current of the lightning surge that has entered the communication line terminal 1 (reference numeral 61) may be bypassed to the communication line terminal 2 (reference numeral 62).

In the configuration of FIG. 8, the SPD 63 and the fuse resistors 71 to 7n are inserted between the communication line terminal 1 (reference numeral 61) and the communication line terminal 2 (reference numeral 62). According to this configuration, the history of lightning surges that have entered the communication line 1 can be confirmed by blowing the fuse resistors 71 to 7n, and the degree of deterioration of the SPD 63 can be determined.

Further, in the electronic devices of the first and second embodiments, a fuse resistor that blows when a certain power is exceeded is connected in parallel, but it can be realized by connecting a fuse that blows when a certain current is exceeded in parallel. Is. In this case, the blown current value of the fuse that blows as the last one in the parallel fuse array is set to the value of Imax described in the first embodiment. In addition, the blown current value of the fuse that blows as the first fuse in the parallel fuse array flows to the fuse that blows as the first fuse as a diversion when a current with a current value of Imin flows through the parallel fuse array. Set so that it is equal to the current value.

Further, even if a circuit in which a fuse and a resistor are connected in series is connected in parallel, the same effect as in the first and second embodiments can be obtained. That is, resistors having different resistance values are connected in series to each of a plurality of fuses of the same standard, and the series connection circuits are further connected in parallel. In this case, the current flowing through each fuse is a shunt of the current flowing through the parallel connection, and the shunt is determined by the resistance value of each resistor. Then, by appropriately selecting the resistance value of each resistor based on the general relationship between the resistance value and the diversion, each time a surge current flows, the fuse is blown in order from the fuse connected in series to the resistor with the lowest resistance value. You can do it. The resistor must have sufficient power resistance characteristics so that the resistor will not be damaged before the fuse blows.

10 Electronic equipment 11 Communication line terminal 12 FG
13 AC power terminal 14 FG
21 SPD
22 Communication circuit 23 SPD
31, 32, 33, 34, 3n fuse resistance 41, 42, 43, 44, 4n fuse resistance 50 Electronic equipment 60 Electronic equipment 61 Communication line terminal 1
62 Communication line terminal 2
63 SPD
64 Communication circuit 71, 72, 7n Fuse resistance 100 Electronic circuit 101 First terminal 102 Second terminal 111 Lightning surge protection element 112, 113 Fusing element

Claims (9)

A lightning surge protection element with an input end connected to the first terminal,
It is provided with an element array in which a plurality of fusing elements having different electrical properties are connected in parallel between the output end of the lightning surge protection element and the second terminal.
When a current flows from the lightning surge protection element to the element array,
The first fusing element in the element arrangement is fused at a predetermined upper limit surge current value which is equal to or less than the discharge withstand capacity of the lightning surge protection element.
In the second fusing element in the element arrangement, only the second fusing element is fluted at a predetermined lower limit surge current value flowing through the element arrangement .
The electrical property is at least one of an electrical resistance value and a fusing current value.
Electronic circuit. The electrical properties include electrical resistance values.
The plurality of fusing elements have fuse resistors having the same fusing power value.
The electric resistance value of the first fusing element is a value obtained by dividing the fusing power value by the square of a predetermined upper limit surge current value which is equal to or less than the discharge withstand capacity of the lightning surge protection element.
The electric resistance value of the second fusing element is a value obtained by multiplying the combined electric resistance value of the element arrangement and a predetermined lower limit surge current value and squared by the fusing power value. The electronic circuit according to claim 1. The electrical properties include fusing current values
The electronic circuit according to claim 1, wherein the plurality of fusing elements are fuses. The electronic circuit according to any one of claims 1 to 3, wherein the second terminal has a ground potential. The first electronic circuit which is the electronic circuit according to any one of claims 1 to 4, and the second electron connected to the first terminal and the second terminal of the first electronic circuit. An electronic device characterized by further providing a circuit. A lightning surge protection element with an input end connected to the first terminal,
In an electronic circuit including an element array in which a plurality of fusing elements having different electrical properties are connected in parallel between an output end of the lightning surge protection element and a second terminal.
When a current flows from the lightning surge protection element to the element array,
The first fusing element in the element arrangement is fused at a predetermined upper limit surge current value which is equal to or less than the discharge withstand capacity of the lightning surge protection element.
In the second fusing element in the element arrangement, only the second fusing element is fluted at a predetermined lower limit surge current value flowing through the element arrangement.
Deterioration of the lightning surge protection element is determined based on the fusing status of the plurality of fusing elements .
The electrical property is at least one of an electrical resistance value and a fusing current value.
How to judge deterioration of lightning surge protection element. The electrical properties include electrical resistance values.
The plurality of fusing elements have fuse resistors having the same fusing power value.
The electric resistance value of the first fusing element is a value obtained by dividing the fusing power value by the square of a predetermined upper limit surge current value which is equal to or less than the discharge withstand capacity of the lightning surge protection element.
The electric resistance value of the second fusing element is a value obtained by multiplying the combined electric resistance value of the element arrangement and a predetermined lower limit surge current value and squared by the fusing power value. The method for determining deterioration of a lightning surge protection element according to claim 6. The electrical properties include fusing current values
The method for determining deterioration of a lightning surge protection element according to claim 6, wherein the plurality of fusing elements are fuses. The method for determining deterioration of a lightning surge protection element according to any one of claims 6 to 8, wherein the second terminal has a ground potential.

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