JPH0487518A - Lightning surge protective circuit - Google Patents

Abstract

PURPOSE:To improve high frequency characteristics of a lightning surge protective circuit by employing a strip conductor rising from a substrate mounting an arrester and then drooping toward the substrate in which the widths of the rising part and the drooping part become narrower as the gap between the substrate becomes narrower. CONSTITUTION:A strip conductor 30 rises against a substrate 20 from an end part 31 and then droops toward an end part 32. In the central part of the strip conductor 30, the lead wire 25 of the other electrode of an arrester ARR penetrates and is electrically bonded to the strip conductor 30 through soldering. The strip conductor 30 is formed narrower as the height of the insulating substrate 20 decreases so that the inductance increases as the capacity increases thus achieving impedance matching.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a lightning surge protection circuit. -For example, used in protectors and amplifiers in cable television (CATV) systems.

[Prior art]

Conventionally, as an example of a lightning surge protection circuit, for example, CATV
In order to prevent surge currents and leakage currents from entering the television receiver through a signal cable, a protector is known that is installed at the eaves of the receiver's house. The protection circuit of this protector basically consists of a circuit that passes high frequencies, a circuit that grounds the DC-ACa component and insulates a pair of signal lines on the output side from the input side in terms of direct current. It consists of an arrester to absorb surges. As this protector, Utility Model Application Publication No. 1-1234 by the present applicant
The one described in Publication No. 30 is known.

[Problem to be solved by the invention]

In lightning surge protection circuits, such as the above-mentioned protector, the arrester is connected to its picture electrode by a lead wire, so in addition to the arrester's self-capacitance, the distributed inductance caused by the lead wire occurs. This has caused deterioration of high frequency characteristics of protectors, amplifiers, etc. when a lightning surge protection circuit is used. Furthermore, it was necessary to insert an inductance into the high-frequency signal line to compensate for the self-capacitance of the arrester.

Means for Solving the Problems The 's1 feature of the present invention comprises an arrester for absorbing lightning surges and a strip conductor connected to the active electrode of the arrester, the strip conductor being connected to the array of the arrester. It has a shape that rises from the substrate and falls toward the substrate, and the rising and falling portions are formed so that the width becomes narrower as the distance from the substrate becomes narrower. be. A second feature of the present invention is an insulating substrate on which a first strip conductor is formed, an arrester whose one electrode is electrically connected to the IJ tube conductor, A strip conductor formed on an insulating substrate is connected to the insulating substrate, rises from the insulating substrate, connects to the other electrode on the top of the arrester, and then falls toward the insulating substrate.
By providing a second strip conductor that is connected to the strip conductor formed on the insulating substrate, and whose rising and falling portions are formed so that the width becomes narrower as the distance from the insulating substrate becomes narrower. be.

[Action and effect of the invention]

In a first feature of the invention, the strip conductor connected to the active electrode of the arrester for absorbing lightning surges rises from the substrate on which the arrester is arranged and falls toward the substrate. The rising and falling portions are formed such that the narrower the distance from the substrate, the narrower the width. In this way, the strip conductor is formed so as to bridge the substrate, and its width is designed according to the distance from the substrate, so that the stray capacitance of the arrester can be efficiently compensated for. As a result, we were able to successfully improve the high frequency characteristics of the lightning surge protection circuit. In addition, in the second feature of the present invention, one electrode of the arrester is arranged in a state connected to the first IJ tube conductor. A second strip conductor is provided which is bridged downward and whose width becomes narrower as the distance from the insulating substrate becomes narrower. This second step) The bridged shape of the IJ tube conductor allows the capacitance and inductance to be designed arbitrarily, and as a result, it is possible to reduce the deterioration of high frequency characteristics caused by inserting the arrester.

【Example】

Hereinafter, the present invention will be explained based on specific examples. FIGS. 1 and 2 are diagrams showing a lightning surge protection circuit according to an embodiment. First strip conductors 21a and 21b, which are ground, are formed on the top and bottom surfaces of the insulating substrate 20. These strip conductors 21a121b are electrically connected by solder 26 that penetrates the insulating substrate 20 at many locations. Further, on the upper surface of the insulating substrate 20, strip conductors 22 and 23, which are live wires for propagating high frequency signals, are formed. The lead wire 24 of one electrode of the arrester ARR passes through the first strip conductor 21a, the insulating substrate 20, and the first strip conductor 21b formed on the back surface thereof, and is connected to the first strip conductor 21b on the back surface by soldering. has been done. On the other hand, a second strip conductor 30 whose end portion 31 is soldered to the strip conductor 22 disposed on the insulating substrate 20 and whose other end portion 32 is soldered to the strip conductor 23 bridges the arrester ARR. It is arranged like this. That is, the second strip conductor 30 is formed in a shape that rises from an end 31 and falls toward an end 32 with respect to the insulating substrate 20 . In the center of the second strip conductor 30,
The lead wire 25 of the other electrode of the arrester ARR penetrates,
The lead wire 25 and the second strip conductor 30 are electrically connected by solder. As is clear from the developed view shown in FIG. 3, this second IJ tube conductor 30 is formed so that its width becomes narrower as its height from the insulating substrate 20 becomes lower. In other words, as the capacitance increases, the inductance also increases,
Impedance matching is achieved. As a result of measuring the transmission characteristics of the lightning surge protection circuit having such a configuration, the characteristics shown in FIG. 4 were obtained. As is clear from this measurement result, the insertion loss is 100100O
Even if it exceeds 0.6 dB, it will not become larger than 0.6 dB. In addition, even if the reflection loss exceeds 100,100 O, it is still within the measurement upper limit of 200 O.
It is 20 dB or more up to 0 MHz. For comparison, the transmission characteristics of a conventional circuit were measured. A cylindrical arrester ARR was arranged as shown in FIG. 7, and the transmission characteristics were measured. At this time, the lead wire of the arrester ARR is made as short as possible. The results are shown in FIG. The insertion loss is 0.5 dB or more at 1400 MHz or more, the reflection loss is 20 dB or less at 600 Jlz or more, and 10 dB or less at 1400 MHz or more. This method has also been conventionally used, but as shown in FIG. 8, when inductance compensation circuits LL and L2 are provided in addition to the arrangement of arrester ARR shown in FIG. 7, the transmission characteristics are as follows. The result is shown in Figure 6. At 1500 MHz or more, the insertion loss is 0.6 dB or more and the reflection loss is 20 dB or less. In this way, in the lightning surge protection circuit of the present invention, 2000
It showed good characteristics in both insertion loss and reflection loss up to the high band of M1 (z). In other embodiments, as shown in FIG. 9, the arrester ARR may be installed vertically by screwing. That is, A conductive pedestal 50 is connected by solder to the first strip conductor 21a formed on the upper surface of the insulating substrate 20, and a screw is cut into the inner surface of the pedestal 50.A ground electrode of the arrester ARR 51 is formed in a ring shape on the side circumference of the arrester,
It has screws cut into it. Then, by screwing these screws together, the arrester ARR is erected on the insulating substrate 20. Alternatively, as shown in FIG. 10, the active electrode of the arrester ARR and the trip conductor may be joined. That is, the electrode 61 of the arrester ARR is formed into a dish shape, and the strip conductor 6
A convex portion 63 is formed on the flat portion 62 of 0. Then, by fitting the convex portion 63 into the dish-shaped electrode 61, the arrester ARR and the strip conductor 60 are electrically and mechanically connected. Further, in the above embodiment, a cylindrical arrester ARR was used, but a neon tube type arrester may be used as shown in FIG. Further, other elements such as diodes may be arranged in addition to the arrester ARR under the strip conductor that bridges the arrester ARR.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a lightning surge protection circuit according to a specific embodiment of the present invention, Fig. 2 is a plan view thereof, Fig. 3 is a developed view of a bridging strip conductor, and Fig. 4 is the protection circuit. Figures 5 and 6 are measurement diagrams showing the transmission characteristics of a conventional arrester protection circuit. Figures 7 and 8 are transmission characteristics of Figures 5 and 6, respectively. A configuration diagram of the arrester protection circuit used in the measurement, FIG. 9 is a sectional view of a protection circuit according to another embodiment, FIG. 10 is a perspective view of a protection circuit according to another embodiment, and FIG. FIG. 2 is a cross-sectional view of a protection circuit according to an example. 20-Insulating substrate 21a, 21b--First strip conductor 22.23.
・Strip conductor 30-...second strip) IJ tube conductor 40.60°°
゛Strip conductor 50°゛pedestal 61 ゛electrode

Claims (2)

[Claims] (1) It consists of an arrester that absorbs lightning surges, and a strip conductor connected to the active electrode of the arrester, and the strip conductor rises from the substrate on which the arrester is disposed and is connected to the substrate. 1. A lightning surge protection circuit having a shape that falls toward the substrate, and the rising and falling portions are formed such that the width becomes narrower as the distance from the substrate becomes narrower. (2) an insulating substrate on which a first strip conductor is formed; an arrester having one electrode electrically connected to the first strip conductor; and a strip conductor formed on the insulating substrate. connected,
It rises from the insulating substrate and is connected to the other electrode on the top of the arrester, then falls toward the insulating substrate and is connected to the strip conductor formed on the insulating substrate, and its rising and falling portions are and a second strip conductor formed such that its width becomes narrower as the distance from the insulating substrate becomes narrower.