EP0033441B1 - Pulse transformer and its use as isolation transformer - Google Patents

Pulse transformer and its use as isolation transformer Download PDF

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Publication number
EP0033441B1
EP0033441B1 EP81100159A EP81100159A EP0033441B1 EP 0033441 B1 EP0033441 B1 EP 0033441B1 EP 81100159 A EP81100159 A EP 81100159A EP 81100159 A EP81100159 A EP 81100159A EP 0033441 B1 EP0033441 B1 EP 0033441B1
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EP
European Patent Office
Prior art keywords
conductors
printed circuit
circuit board
series
layers
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP81100159A
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German (de)
French (fr)
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EP0033441A1 (en
Inventor
Heinrich Ryser
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Hasler AG
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Hasler AG
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Priority to AT81100159T priority Critical patent/ATE9419T1/en
Publication of EP0033441A1 publication Critical patent/EP0033441A1/en
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Publication of EP0033441B1 publication Critical patent/EP0033441B1/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F17/00—Fixed inductances of the signal type 
    • H01F17/0006—Printed inductances
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F17/00—Fixed inductances of the signal type 
    • H01F17/04—Fixed inductances of the signal type  with magnetic core
    • H01F17/06—Fixed inductances of the signal type  with magnetic core with core substantially closed in itself, e.g. toroid
    • H01F17/062—Toroidal core with turns of coil around it
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F19/00—Fixed transformers or mutual inductances of the signal type
    • H01F19/04—Transformers or mutual inductances suitable for handling frequencies considerably beyond the audio range
    • H01F19/08—Transformers having magnetic bias, e.g. for handling pulses
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F5/00—Coils
    • H01F5/04—Arrangements of electric connections to coils, e.g. leads
    • H01F2005/046—Details of formers and pin terminals related to mounting on printed circuits
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F17/00—Fixed inductances of the signal type 
    • H01F17/04—Fixed inductances of the signal type  with magnetic core
    • H01F17/06—Fixed inductances of the signal type  with magnetic core with core substantially closed in itself, e.g. toroid
    • H01F2017/065—Core mounted around conductor to absorb noise, e.g. EMI filter
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F19/00—Fixed transformers or mutual inductances of the signal type
    • H01F19/04—Transformers or mutual inductances suitable for handling frequencies considerably beyond the audio range
    • H01F19/08—Transformers having magnetic bias, e.g. for handling pulses
    • H01F2019/085—Transformer for galvanic isolation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/2847—Sheets; Strips
    • H01F2027/2861—Coil formed by folding a blank

Definitions

  • the invention relates to a pulse transformer with an annular, seamlessly closed core and with primary and secondary windings according to the preamble of claim 1.
  • Pulse transformers also called pulse transformers, should be small and have good transmission properties, which means above all rapid pulse rise and fall times. This leads to the preference of closed, seamless toroids as the transformer core.
  • toroidal cores have the disadvantage that the windings cannot be attached in a way that is favorable to the work.
  • pulse transmitters on the market today, the wire turns of which are formed by U-shaped wire brackets, which are connected by soldering to star-shaped conductor tracks of a supporting printed circuit board to form “windings” (described, for example, by the document FR-A-2394878). Furthermore, pulse transmitters are known in which magnetic material is introduced in a special way into the central, concentric opening of the primary and secondary windings, so that a complete transformer transmitter results. A similar way is shown by the document US-A-3 659 240, according to which two coils and thus a complete pulse transmitter are formed by successively applying thick film conductor segments to a closed magnetic core.
  • a toroidal coil with a printed winding is known, which is suitable as a transmitter for high frequencies.
  • the printed winding is composed of U-shaped conductor tracks, which are arranged on a rigid, appropriately shaped circuit board, and which, after being inserted with one leg of the U through the toroid, are soldered to the conductor tracks of a supporting circuit board in such a way that there are several complete windings.
  • a transducer is known from IBM Technical Disclosure Bulletin, volume 12, number 6, November 1969, New York, in which a flexible carrier plate with a plurality of printed parallel conductor lines is used to form a coil.
  • the carrier plate together with the conductor tracks is pulled through the opening of a rectangular core and bent together in a loop in such a way that the conductor tracks join together.
  • the conductor tracks are then soldered or otherwise electrically connected to one another.
  • the object of the invention is therefore to provide an easy-to-manufacture pulse transformer, the windings of which are shielded against all electromagnetic interference coming from outside.
  • the aim is to shield such faults that are introduced via line shields and / or grounded line parts of connecting lines, etc.
  • Claims 2 to 13 represent different embodiments of the invention, while claims 14 to 16 provide information about the use of the pulse transmitters defined by the preceding claims and about the arrangement of the pulse transmitter on a printed circuit board in this use.
  • the pulse transmitter according to the invention has very good electrical properties, that the digital signals transmitted by the transmitter are hardly influenced by external interference and that the manufacturing costs are significantly reduced compared to the known pulse transmitters. Furthermore, when using the pulse transmitter, there are simplifications in the connection electronics and elegant possibilities for the combination of signal and feed lines, which meet the highest security requirements.
  • Fig. 1 shows a section through a pulse transmitter mounted on a supporting circuit board.
  • 11 is this printed circuit board, which is composed of a three-layer plate made of insulating material 12, a lower conductor layer 13, an upper conductor layer 14 and a middle conductor layer 15.
  • a coaxial cable 20, preferably via a coaxial connector, is connected to the printed circuit board 11.
  • the central conductor 21 of the coaxial cable 20 is conductively connected to a conductor path in the central conductor layer 15 via a cutout 22 in the upper conductor layer 14.
  • 23 is a cross connection via which the shielding of the coaxial cable 20 is connected to the lower (13) and the upper conductor layer 14 of the supporting printed circuit board 11.
  • the width of the conductor strip 15 in the middle conductor layer is designed such that, together with the distance between the layers 15, 13 and 14 and with the electrical properties of the insulating material 12, there is a characteristic impedance which corresponds to that of the coaxial cable 20.
  • This characteristic impedance can be, for example, 75 ⁇ .
  • Both printed circuit boards are loop-shaped and mechanically and at least partially electrically connected to the supporting printed circuit board 11 via pins 36 to 39 or 46 to 49.
  • the pin 39 connects the lower (13) and upper (14) conductor layers of the load-bearing circuit board 11 with corresponding layers of the flexible circuit board 31.
  • the pin 36 connects the conductor track 15 to the start of the primary winding.
  • the remaining pins 37 and 38 exclusively connect points of the flexible printed circuit board 31 to one another. The type of connection is discussed in detail below with reference to FIG. 2.
  • a non-conductive intermediate area 42 which corresponds to a corresponding intermediate area 41 on the underside of the printed circuit board 11.
  • These intermediate regions 41 and 42 provide a galvanic separation between the conductor regions 13 and 14 which are at the potential of the coaxial cable sheath and the conductor regions 43 and 44 which are at the arbitrary reference potential of an electronic circuit, for example an amplifier or driver circuit. This creates a complete electrical isolation between the input and the output area of the pulse transmitter.
  • FIG. 2 shows an exploded drawing of the printed circuit board designated 31 in FIG. 1, which has the shape of a flat strip.
  • 51 to 57 are seven superimposed and welded layers, of which layers 51, 53, 55 and 57 consist of insulating material and layers 52, 54 and 56 consist of metal, for example copper. All layers have a distinct longitudinal direction, which is large compared to their transverse direction. All layers have no holes or connections in the middle area. Rather, these are arranged at the ends of the multilayer printed circuit board.
  • the dimensions of the circuit board can be, for example, 0.5 x 5 x 50 mm.
  • the upper metal layer 52 has two cutouts 71 and 72 and a solder connection 70.
  • the lower metal layer 56 has corresponding cutouts 87 and 86 and a solder connection 88, which are arranged in mirror image to the corresponding cutouts or connections of the layer 52.
  • the middle metal layer 54 comprises, for example, three conductor tracks 82 to 84, which are delimited by two solder connections 75 to 81, which are arranged in two rows one behind the other in the longitudinal direction.
  • All layers 51 to 57 lying one above the other in the welded state have through-holes 60 to 67 which are plated through at the locations where a soldering support point is arranged in any of the layers, i.e. the walls of which are metallically conductive and are electrically connected to the soldering point (s) in the various metal layers 52, 54 and / or 56.
  • a winding of three turns is formed, which is connected to the central conductor 21 of the coaxial cable 20 via the conductor 15 and the pin 36.
  • the three windings consist of the conductors 82, 83 and 84 and the pins 37 and 38. The end of this winding is connected via the pin 39 to the conductor layers 13 and 14 of the supporting printed circuit board 11 and thus to the potential of the jacket of the coaxial cable 20.
  • the layers 52 and 56 of the flexible printed circuit board 31 are each connected via a point to the conductive layers 13 and 14 in the soldered state and form two shielding layers which almost completely surround the winding described. Although these shielding layers are bent in a ring, they do not form closed rings.
  • the bending direction of the shielding layers with respect to their connection points 70 and 88 is in opposite directions and their width is so large that they broadly cover the conductor runs 82 to 84 between them, which form the winding. Taking into account the small layer thicknesses of layers 53 to 54, this ensures that the conductor tracks are shielded on all sides against electromagnetic interference.
  • the primary and secondary windings can be formed by flexible printed circuit boards 31 and 32 of the same type be educated.
  • a pulse transformer is created with a gear ratio of 1: 1.
  • other transmission ratios can also be produced in a simple manner.
  • a connecting pin can be provided as the center tap, which results in a winding with two plus two turns.
  • FIGS. 1 and 2 there are a number of variants.
  • One of these variants consists in forming the layers 52 and 56 of the flexible printed circuit board not in mirror image, but rather in an identical manner. When the circuit board is bent in a loop, two shielding layers are created which have the same bending direction with regard to their connection points.
  • a conductor layer which has more or less than three conductor tracks can be used instead of a layer 54 which has three parallel conductor tracks 82 to 84. Furthermore, instead of such a layer, a plurality of such layers can be arranged one above the other, as a result of which windings with more than three turns can be produced.
  • a two-layer plate according to FIG. 3 can be provided.
  • the four conductor tracks 90 to 93 which have connection points at their two ends and are used for winding production, are arranged on one side 94 of the plate.
  • By folding the plate parallel to the conductor tracks 90 to 93 one half of the layer 96 is placed over these conductor tracks 90 to 93, while the other half remains on the underside. In this way, a unit is created which is made up of interconnects which are insulated from one another and which is shielded on all sides from the outside.
  • An insulating cover layer 97 provides insulation from the outside and enables welding at the otherwise open fold end 98.
  • a functionally identical unit can be constructed in which the conductor tracks for forming the winding consist of insulated wires, for example enamelled wires.
  • 4a shows a top view of these staggered parallel wires 101 to 103, which are held on the top and bottom by an insulating layer each carrying a conductor layer, so that in turn there is a unit in which conductors lying in the middle with connection points are shielded from the outside by shielding layers at both ends.
  • the connection points can either be formed by the wires 101 to 103 being led out to the side or by drill holes 104 to 106 which are provided in such a way that one wire is drilled to the side and thus stripped.
  • the holes formed in this way can be plated through and thus correspond completely to the holes 60 to 67 of FIG. 2.
  • Fig. 4b shows such a unit that is bent into a loop.
  • the protruding wires 101 to 103 are soldered with their stripped ends directly in the holes 104 to 106.
  • the pins 36 to 39 and 46 to 49 shown in FIG. 1 are therefore unnecessary.
  • two or more ferrite cores 30.1, 30.2, 30.3 arranged coaxially next to one another can serve as the transformer core, through whose openings the flexible printed circuit boards 31 and 32 pass (FIG. 6).
  • the coaxial cable 20 can only be mechanically fastened to the supporting printed circuit board 11 and its central conductor 21 can be connected directly to the start of the winding of the flexible printed circuit board 31.
  • the shielding layers 52 and 56 of the flexible printed circuit board can be narrowed in the shape of a dumbbell in the middle in order to obtain improved insulating ability of the insulating layer welding at the bending points.
  • the flexible printed circuit boards 31 and 32 can also push through the core in a slightly arcuate manner as shown in FIG. 5.
  • the flexible printed circuit board 89 is fixed electrically and mechanically on both sides of the toroidal core 30 with pins 191 to 198 on a supporting printed circuit board 11.
  • the conductor tracks corresponding to 82, 83 and 84 of FIG. 2 can either be supplemented by conductor tracks 90 on the supporting printed circuit board 11 or by a second flexible printed circuit board which does not penetrate the toroidal core 30.
  • FIG. 6 shows schematically a holder 110 for a complete pulse transmitter, which is composed of three seamless ferrite cores 30.1, 30.2 and 30.3 which are coaxially one above the other and two loop-shaped winding units, for example printed circuit boards 31 and 32 of the type described with reference to FIG. 2.
  • the pins 112 and 113 of the right unit connect the conductor tracks forming the winding in the manner described and fix the unit to the holder.
  • the remaining pins 111 and 114 are led out of the holder 110 and serve as a soldering pin for connection to the carrier circuit board 11.
  • the winding unit shows an extension 115 which has an additional shielding layer electrically connected to the shielding layers of the flexible circuit board 31. This extension 115 is bent in a lug shape over the pin ends and shields them electrically.
  • the layer 14 of the carrier circuit board 11 takes over the corresponding function. This further improves the shielding properties.
  • the winding sense of the loops of the two winding units of a pulse transformer can be na of course in the same direction according to Fig. or in slightly changed geometry also in opposite directions.
  • Pulse transformers of the type described are used, for example, as isolating transformers between an electronic circuit arrangement and a transmission line for the transmission of fast digital signals.
  • the transmission line can, as shown in FIG. 1, be designed as a coaxial cable 20 or as another cable suitable for digital signals, for example a four-wire line consisting of two wire pairs.
  • a feed current can flow on this in a manner known per se.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Multimedia (AREA)
  • Coils Or Transformers For Communication (AREA)
  • Arrangements For Transmission Of Measured Signals (AREA)
  • Dc Digital Transmission (AREA)

Abstract

The pulse transformer consists of a closed toroidal core (30), the primary winding (31) and secondary winding (32) of which are fashioned as multilayer, flexible printed circuit boards. These circuit boards have the shape of flat strips and are bent into loops. By means of pins (36-39 and 46-49, respectively), they are connected mechanically and partially electrically to a supporting printed circuit board (11). The pins connect the conductor tracks of the central layer of the flexible printed circuit boards with respectively one winding, whereas the upper and lower conductive layers shield the windings against electromagnetic interferences coming from the outside. The pulse transformer is suitable as an isolation transformer for the transmission of rapid digital signals arriving, for example, via a coaxial line (20).

Description

Die Erfindung betrifft einen Impulsübertrager mit ringförmigem, nahtlos geschlossenem Kern und mit Primär- und Sekundärwicklungen entsprechend dem Oberbegriff von Anspruch 1.The invention relates to a pulse transformer with an annular, seamlessly closed core and with primary and secondary windings according to the preamble of claim 1.

lmpulsübertrager, auch Impulstransformatoren genannt, sollen klein sein und gute Übertragungseigenschaften aufweisen, was vor allem schnelle Impulsanstiegs- und Abfallzeiten bedeutet. Dies führt zur Bevorzugung geschlossener, nahtloser Ringkerne als Übertragerkern. Derartige Ringkerne haben jedoch den Nachteil, dass die Wicklungen nicht arbeitsgünstig anbringbar sind.Pulse transformers, also called pulse transformers, should be small and have good transmission properties, which means above all rapid pulse rise and fall times. This leads to the preference of closed, seamless toroids as the transformer core. However, such toroidal cores have the disadvantage that the windings cannot be attached in a way that is favorable to the work.

Auf dem Markt sind heute Impulsübertrager, deren Drahtwindungen durch U-förmige Drahtbügel gebildet werden, die durch Verlöten mit sternförmig angeordneten Leiterbahnen einer tragenden Leiterplatte zu «Wicklungen» verbunden sind (beschrieben beispielsweise durch die Schrift FR-A-2394878). Weiter sind lmpulsübertrager bekannt, bei denen in die zentrale, konzentrische Öffnung der Primär- und Sekundärwicklung auf spezielle Weise Magnetmaterial eingebracht wird, so dass sich ein vollständiger transformatorischer Übertrager ergibt. Ein ähnlicher Weg wird durch die Schrift US-A-3 659 240 aufgezeigt, wonach durch sukzessives Aufbringen von Dickfilm-Leitersegmenten auf einen geschlossenen Magnetkern zwei Spulen und damit ein vollständiger Impulsübertrager gebildet werden.There are pulse transmitters on the market today, the wire turns of which are formed by U-shaped wire brackets, which are connected by soldering to star-shaped conductor tracks of a supporting printed circuit board to form “windings” (described, for example, by the document FR-A-2394878). Furthermore, pulse transmitters are known in which magnetic material is introduced in a special way into the central, concentric opening of the primary and secondary windings, so that a complete transformer transmitter results. A similar way is shown by the document US-A-3 659 240, according to which two coils and thus a complete pulse transmitter are formed by successively applying thick film conductor segments to a closed magnetic core.

Aus der Schrift CH-A-468 065 ist eine Ringkernspule mit gedruckter Wicklung bekannt, die als Übertrager für hohe Frequenzen geeignet ist. Die gedruckte Wicklung setzt sich aus U-förmigen Leiterzügen zusammen, die auf einer starren, entsprechend geformten Leiterplatte angeordnet sind, und die nachdem sie mit dem einen Schenkel des U's durch den Ringkern gesteckt sind, mit den Leiterzügen einer tragenden Leiterplatte so verlötet sind, dass sich mehrere vollständige Wicklungen ergeben.From the document CH-A-468 065 a toroidal coil with a printed winding is known, which is suitable as a transmitter for high frequencies. The printed winding is composed of U-shaped conductor tracks, which are arranged on a rigid, appropriately shaped circuit board, and which, after being inserted with one leg of the U through the toroid, are soldered to the conductor tracks of a supporting circuit board in such a way that there are several complete windings.

Aus IBM Technical Disclosure Bulletin, Band 12, Heft 6, November 1969, New York, ist ein Transducer bekannt, bei dem eine flexible Trägerplatte mit mehreren gedruckten parallelen Leiterzügen zur Bildung einer Spule dient. Die Trägerplatte wird hierzu samt der Leiterzüge durch die Öffnung eines Rechteckkerns gezogen und schleifenförmig so zusammengebogen, dass sich die Leiterzüge zusammenfügen. Die Leiterzüge werden hierauf verlötet oder anderweitig elektrisch miteinander verbunden.A transducer is known from IBM Technical Disclosure Bulletin, volume 12, number 6, November 1969, New York, in which a flexible carrier plate with a plurality of printed parallel conductor lines is used to form a coil. For this purpose, the carrier plate together with the conductor tracks is pulled through the opening of a rectangular core and bent together in a loop in such a way that the conductor tracks join together. The conductor tracks are then soldered or otherwise electrically connected to one another.

Aus der Schrift US-A-3 267 402 ist schliesslich noch ein Solenoid für Magnetspeicher bekannt, bei dem ebenfalls eine flexible, gedruckte Leiterplatte zur Anwendung kommt. Diese Platte trägt parallele Leiterzüge, deren eine Anschlüsse seitlich versetzt sind. Die Platte wird in mehreren Windungen um das Twistorkabel des Speichers gewickelt und die versetzten Anschlüsse entweder durch Löcher in der Platte oder seitlich der Platte von der innersten Windung nach aussen geführt.From US-A-3 267 402 there is finally known a solenoid for magnetic memories, in which a flexible, printed circuit board is also used. This plate carries parallel conductors, one of which connections are laterally offset. The plate is wound in several turns around the twisted-pair cable of the memory and the staggered connections are led either from the innermost turn to the outside through holes in the plate or to the side of the plate.

Bei lmpulsübertragern, die für hohe Impulsfolgefrequenzen verwendet werden, beispielsweise für 16 MHz, ist es günstig, wenn die Wicklungen des Übertragers gegen äussere elektromagnetische Störungen abgeschirmt sind. Eine derartige Abschirmung ist bei den bekannten Übertragern jedoch nicht ohne weiteres anbringbar.In the case of pulse transmitters which are used for high pulse repetition frequencies, for example for 16 MHz, it is advantageous if the windings of the transmitter are shielded against external electromagnetic interference. Such a shield is not readily attachable to the known transformers.

Die Aufgabe der Erfindung besteht daher darin, einen einfach zu fertigenden Impulsübertrager anzugeben, dessen Wicklungen gegen alle von aussen kommenden elektromagnetischen Störungen abgeschirmt sind. Insbesondere wird angestrebt, auch solche Störungen abzuschirmen, die über Leitungsabschirmungen und/oder geerdete Leitungsteile von Anschlussleitungen usw. eingeschleust werden.The object of the invention is therefore to provide an easy-to-manufacture pulse transformer, the windings of which are shielded against all electromagnetic interference coming from outside. In particular, the aim is to shield such faults that are introduced via line shields and / or grounded line parts of connecting lines, etc.

Die Lösung dieser Aufgabe wird durch den kennzeichnenden Teil des ersten Patentanspruchs angegeben.The solution to this problem is given by the characterizing part of the first claim.

Die Ansprüche 2 bis 13 geben verschiedene Ausgestaltungen der Erfindung wieder, während die Ansprüche 14 bis 16 Angaben über die Verwendung der durch die vorhergehenden Ansprüche definierten Impulsübertrager sowie über die Anordnung des Impulsübertragers auf einer Leiterplatte bei dieser Verwendung machen.Claims 2 to 13 represent different embodiments of the invention, while claims 14 to 16 provide information about the use of the pulse transmitters defined by the preceding claims and about the arrangement of the pulse transmitter on a printed circuit board in this use.

Es hat sich gezeigt, dass der erfindungsgemässe Impulsübertrager sehr gute elektrische Eigenschaften aufweist, dass die durch den Übertrager übertragenen Digitalsignale durch äussere Störungen kaum beeinflusst werden und dass die Herstellungskosten gegenüber den bekannten Impulsübertragern wesentlich vermindert sind. Weiter ergeben sich bei Verwendung der lmpulsübertrager Vereinfachungen bei der Anschlusselektronik und elegante Möglichkeiten für die Kombination von Signal- und Speiseleitungen, die höchsten Sicherheitsanforderungen genügt.It has been shown that the pulse transmitter according to the invention has very good electrical properties, that the digital signals transmitted by the transmitter are hardly influenced by external interference and that the manufacturing costs are significantly reduced compared to the known pulse transmitters. Furthermore, when using the pulse transmitter, there are simplifications in the connection electronics and elegant possibilities for the combination of signal and feed lines, which meet the highest security requirements.

Im folgenden wird anhand von 6 Figuren die Erfindung beispielsweise näher erläutert. Es zeigen:

  • Fig. 1 Schnittzeichnung durch einen auf eine tragende Leiterplatte montierten lmpulsübertrager,
  • Fig. 2 Explosionszeichnung einer mehrschichtigen, flexiblen Leiterplatte,
  • Fig. 3 Schnitt durch eine flexible Leiterplatte,
  • Fig. 4a Aufsicht auf eine flexible Einheit mit Isolierdrähten,
  • Fig. 4b Seitenansicht derselben Einheit,
  • Fig. 5 Schnittzeichnung durch einen zweiten auf eine tragende Leiterplatte montierten Impulsübertrager,
  • Fig. 6 Halterung für einen Impulsübertrager.
The invention is explained in more detail below with reference to 6 figures. Show it:
  • 1 shows a sectional drawing through a pulse transmitter mounted on a load-bearing circuit board,
  • 2 exploded view of a multilayer, flexible circuit board,
  • 3 section through a flexible printed circuit board,
  • 4a top view of a flexible unit with insulating wires,
  • 4b side view of the same unit,
  • 5 shows a sectional drawing through a second pulse transmitter mounted on a load-bearing circuit board,
  • Fig. 6 bracket for a pulse transmitter.

Fig. 1 zeigt einen Schnitt durch einen auf eine tragende Leiterplatte montierten Impulsübertrager. 11 ist diese Leiterplatte, die als dreischichtige Platte aus Isoliermaterial 12, einer unteren Leiterschicht 13, einer oberen Leiterschicht 14 und einer mittleren Leiterschicht 15 zusammengesetzt ist. An die Leiterplatte 11 ist ein Koaxialkabel 20, bevorzugt über einen Koaxialstecker, angeschlossen. Der Mittelleiter 21 des Koaxialkabels 20 ist über eine Aussparung 22 in der oberen Leiterschicht 14 mit einem Leiterzug in der mittleren Leiterschicht 15 leitend verbunden. 23 ist eine Querverbindung, über die die Abschirmung des Koaxialkabels 20 mit der unteren (13) und der oberen Leiterschicht 14 der tragenden Leiterplatte 11 verbunden ist.Fig. 1 shows a section through a pulse transmitter mounted on a supporting circuit board. 11 is this printed circuit board, which is composed of a three-layer plate made of insulating material 12, a lower conductor layer 13, an upper conductor layer 14 and a middle conductor layer 15. A coaxial cable 20, preferably via a coaxial connector, is connected to the printed circuit board 11. The central conductor 21 of the coaxial cable 20 is conductively connected to a conductor path in the central conductor layer 15 via a cutout 22 in the upper conductor layer 14. 23 is a cross connection via which the shielding of the coaxial cable 20 is connected to the lower (13) and the upper conductor layer 14 of the supporting printed circuit board 11.

Der Leiterzug 15 in der mittleren Leiterschicht ist in seiner Breite so ausgebildet, dass sich zusammen mit dem Abstand zwischen den Schichten 15, 13 und 14 sowie mit den elektrischen Eigenschaften des Isoliermaterials 12 ein Wellenwiderstand ergibt, der demjenigen des Koaxialkabels 20 entspricht. Dieser Wellenwiderstand kann beispielsweise 75 Ω betragen.The width of the conductor strip 15 in the middle conductor layer is designed such that, together with the distance between the layers 15, 13 and 14 and with the electrical properties of the insulating material 12, there is a characteristic impedance which corresponds to that of the coaxial cable 20. This characteristic impedance can be, for example, 75 Ω.

30 ist ein nahtloser ferromagnetischer Ringkern, durch dessen Öffnung zur Bildung der Primär- und der Sekundärwicklung eines Impulsübertragers zwei flexible Leiterplatten 31 und 32 hindurchführen. Beide Leiterplatten sind schleifenförmig gebogen und über Stifte 36 bis 39 bzw. 46 bis 49 mit der tragenden Leiterplatte 11 mechanisch und zumindest teilweise elektrisch verbunden. So verbindet der Stift 39 beispielsweise die untere (13) und obere (14) Leiterschicht der tragenden Leiterplatte 11 mit entsprechenden Schichten der flexiblen Leiterplatte 31. Der Stift 36 verbindet den Leiterzug 15 mit dem Wicklungsanfang der Primärwicklung. Die übrigen Stifte 37 und 38 verbinden ausschliesslich Punkte der flexiblen Leiterplatte 31 untereinander. Die Art und Weise der Verbindungen wird anhand von Fig. 2 weiter unten eingehend besprochen.30 is a seamless ferromagnetic toroidal core through whose opening two flexible printed circuit boards 31 and 32 pass through to form the primary and secondary windings of a pulse transformer. Both printed circuit boards are loop-shaped and mechanically and at least partially electrically connected to the supporting printed circuit board 11 via pins 36 to 39 or 46 to 49. For example, the pin 39 connects the lower (13) and upper (14) conductor layers of the load-bearing circuit board 11 with corresponding layers of the flexible circuit board 31. The pin 36 connects the conductor track 15 to the start of the primary winding. The remaining pins 37 and 38 exclusively connect points of the flexible printed circuit board 31 to one another. The type of connection is discussed in detail below with reference to FIG. 2.

Zwischen der oberen Leiterschicht 14 auf der rechten Seite von Fig. 1 und der entsprechenden Schicht 44 links befindet sich ein nichtleitender Zwischenbereich 42, dem ein entsprechender Zwischenbereich 41 auf der Unterseite der Leiterplatte 11 entspricht. Durch diese Zwischenbereiche 41 und 42 erfolgt eine galvanische Trennung zwischen den auf dem Potential des Koaxialkabelmantels liegenden Leiterbereichen 13 und 14 und den Leiterbereichen 43 und 44, die auf dem beliebigen Bezugspotential einer Elektronikschaltung liegen, beispielsweise einer Verstärker- oder Treiberschaltung. Hierdurch entsteht eine vollständige galvanische Trennung zwischen dem Eingangs- und dem Ausgangsbereich des Impulsübertragers.Between the upper conductor layer 14 on the right side of FIG. 1 and the corresponding layer 44 on the left there is a non-conductive intermediate area 42, which corresponds to a corresponding intermediate area 41 on the underside of the printed circuit board 11. These intermediate regions 41 and 42 provide a galvanic separation between the conductor regions 13 and 14 which are at the potential of the coaxial cable sheath and the conductor regions 43 and 44 which are at the arbitrary reference potential of an electronic circuit, for example an amplifier or driver circuit. This creates a complete electrical isolation between the input and the output area of the pulse transmitter.

Fig. 2 zeigt eine Explosionszeichnung der in Fig. 1 mit 31 bezeichneten Leiterplatte, die die Form eines Flachbandes aufweist. 51 bis 57 sind sieben übereinanderliegende und miteinander verschweisste Schichten, von denen die Schichten 51, 53, 55 und 57 aus Isoliermaterial und die Schichten 52, 54 und 56 aus Metall, beispielsweise aus Kupfer, bestehen. Alle Schichten besitzen eine deutliche Längsrichtung, die gross ist gegenüber ihrer Querrichtung. Alle Schichten besitzen im mittleren Bereich keine Löcher oder Anschlüsse. Diese sind vielmehr an den Enden der mehrschichtigen Leiterplatte angeordnet. Die Dimensionen der Leiterplatte können beispielsweise 0,5 x 5 x 50 mm betragen.FIG. 2 shows an exploded drawing of the printed circuit board designated 31 in FIG. 1, which has the shape of a flat strip. 51 to 57 are seven superimposed and welded layers, of which layers 51, 53, 55 and 57 consist of insulating material and layers 52, 54 and 56 consist of metal, for example copper. All layers have a distinct longitudinal direction, which is large compared to their transverse direction. All layers have no holes or connections in the middle area. Rather, these are arranged at the ends of the multilayer printed circuit board. The dimensions of the circuit board can be, for example, 0.5 x 5 x 50 mm.

Die obere Metallschicht 52 besitzt zwei Aussparungen 71 und 72 sowie einen Lötanschluss 70. Die untere Metallschicht 56 besitzt entsprechende Aussparungen 87 und 86 und einen Lötanschluss 88, welche spiegelbildlich zu den entsprechenden Aussparungen bzw. Anschlüssen der Schicht 52 angeordnet sind. Die mittlere Metallschicht 54 umfasst beispielsweise drei Leiterzüge 82 bis 84, die durch je zwei Lötanschlüsse 75 bis 81 begrenzt sind, die in zwei Reihen in Längsrichtung hintereinander angeordnet sind.The upper metal layer 52 has two cutouts 71 and 72 and a solder connection 70. The lower metal layer 56 has corresponding cutouts 87 and 86 and a solder connection 88, which are arranged in mirror image to the corresponding cutouts or connections of the layer 52. The middle metal layer 54 comprises, for example, three conductor tracks 82 to 84, which are delimited by two solder connections 75 to 81, which are arranged in two rows one behind the other in the longitudinal direction.

Alle im verschweissten Zustand übereinanderliegenden Schichten 51 bis 57 besitzen an den Stellen, an denen in irgendeiner der Schichten ein Lötstützpunkt angeordnet ist, durchgehende Löcher 60 bis 67, die durchplattiert sind, d.h. deren Wände metallisch leitend und mit dem oder den Lötstützpunkt(en) in den verschiedenen Metallschichten 52, 54 und/oder 56 elektrisch verbunden sind.All layers 51 to 57 lying one above the other in the welded state have through-holes 60 to 67 which are plated through at the locations where a soldering support point is arranged in any of the layers, i.e. the walls of which are metallically conductive and are electrically connected to the soldering point (s) in the various metal layers 52, 54 and / or 56.

Die Zusammenstellung des Impulsübertragers erfolgt dadurch, dass die flexiblen Leiterplatten 31 und 32 durch den Ringkern 30 geschoben und anschliessend schleifenförmig in der in Fig. 1 gezeigten Weise zurechtgebogen werden. Durch Einführen der in Fig. 1 gezeigten Stifte 36 bis 39 bzw. 46 bis 49 in die übereinanderliegenden Löcher 63 und 64, 62 und 65, 61 und 66 bzw. 60 und 67 und durch Verlöten dieser Stifte mit den durchplattierten Löchern entstehen folgende Verbindungen mit der Leiterplatte 11:

  • - Stift 39 verbindet über die Löcher 60 und 67 die Lötstützpunkte 70, 81 und 88 mit den Leiterschichten 13 und 14 der tragenden Leiterplatte 11.
  • - Stift 38 verbindet über die Löcher 61 und 66 die Lötstützpunkte 75 und 80 miteinander.
  • - Stift 37 verbindet über die Löcher 62 und 65 die Lötstützpunkte 76 und 79 miteinander.
  • - Stift 36 verbindet über die Löcher 63 und 64 die Lötstützpunkte 77 und 78 mit dem Leiterzug 15 der tragenden Leiterplatte 11.
The pulse transmitter is assembled by pushing the flexible printed circuit boards 31 and 32 through the toroidal core 30 and then bending them in a loop in the manner shown in FIG. 1. By inserting the pins 36 to 39 or 46 to 49 shown in FIG. 1 into the holes 63 and 64, 62 and 65, 61 and 66 or 60 and 67 one above the other and by soldering these pins to the plated-through holes, the following connections are formed PCB 11:
  • - Pin 39 connects the soldering support points 70, 81 and 88 to the conductor layers 13 and 14 of the load-bearing circuit board 11 via the holes 60 and 67.
  • - Pin 38 connects the soldering support points 75 and 80 to one another via the holes 61 and 66.
  • - Pin 37 connects the soldering support points 76 and 79 with one another via the holes 62 and 65.
  • - Pin 36 connects the soldering support points 77 and 78 to the conductor 15 of the load-bearing circuit board 11 via the holes 63 and 64.

Auf diese Weise entsteht eine Wicklung von drei Windungen, die mit dem Mittelleiter 21 des Koaxialkabels 20 über den Leiterzug 15 und den Stift 36 verbunden ist. Die drei Wicklungen bestehen aus den Leiterzügen 82, 83 und 84 sowie den Stiften 37 und 38. Das Ende dieser Wicklung ist über den Stift 39 mit den Leiterschichten 13 und 14 der tragenden Leiterplatte 11 und damit mit dem Potential des Mantels des Koaxilakabels 20 verbunden.In this way, a winding of three turns is formed, which is connected to the central conductor 21 of the coaxial cable 20 via the conductor 15 and the pin 36. The three windings consist of the conductors 82, 83 and 84 and the pins 37 and 38. The end of this winding is connected via the pin 39 to the conductor layers 13 and 14 of the supporting printed circuit board 11 and thus to the potential of the jacket of the coaxial cable 20.

Die Schichten 52 und 56 der flexiblen Leiterplatte 31 sind im verlöteten Zustand je über einen Punkt mit den leitenden Schichten 13 und 14 verbunden und bilden zwei Abschirmschichten, die die beschriebene Wicklung fast vollständig umgeben. Diese Abschirmungsschichten sind zwar ringförmig gebogen, bilden aber keine geschlossenen Ringe. Die Biegerichtung der Abschirmschichten bezüglich ihrer Anschlusspunkte 70 bzw. 88 ist gegensinnig und ihre Breite ist so gross, dass sie die zwischen ihnen liegenden Leiterzüge 82 bis 84, die die Wicklung bilden, breit überdecken. Damit ist bei Berücksichtigung der geringen Schichtdicken der Schichten 53 bis 54 sichergestellt, dass die Leiterzüge allseitig gegen elektromagnetische Störungen abgeschirmt sind.The layers 52 and 56 of the flexible printed circuit board 31 are each connected via a point to the conductive layers 13 and 14 in the soldered state and form two shielding layers which almost completely surround the winding described. Although these shielding layers are bent in a ring, they do not form closed rings. The bending direction of the shielding layers with respect to their connection points 70 and 88 is in opposite directions and their width is so large that they broadly cover the conductor runs 82 to 84 between them, which form the winding. Taking into account the small layer thicknesses of layers 53 to 54, this ensures that the conductor tracks are shielded on all sides against electromagnetic interference.

Beim Impulsübertrager entsprechend Fig. 1 können die Primär- und die Sekundärwicklung durch gleichartige flexible Leiterplatten 31 bzw. 32 gebildet sein. In diesem Fall entsteht ein Impulsübertrager, dessen Übersetzungsverhältnis 1 : 1 beträgt. Durch Verwendung verschiedener Leiterplatten können jedoch auf einfache Weise auch andere Übersetzungsverhältnisse hergestellt werden. Weiter kann bei beispielsweise vier Leiterzügen der mittleren Schicht 54 ein Verbindungsstift als Mittelabgriff vorgesehen werden, wodurch eine Wicklung mit zwei plus zwei Windungen entsteht.1, the primary and secondary windings can be formed by flexible printed circuit boards 31 and 32 of the same type be educated. In this case, a pulse transformer is created with a gear ratio of 1: 1. By using different printed circuit boards, however, other transmission ratios can also be produced in a simple manner. Furthermore, in the case of, for example, four conductor tracks of the middle layer 54, a connecting pin can be provided as the center tap, which results in a winding with two plus two turns.

Neben den in Fig. 1 und 2 gezeigten beispielsweisen Ausführung der Erfindung gibt es eine Reihe von Varianten. Eine dieser Varianten besteht darin, die Schichten 52 und 56 der flexiblen Leiterplatte nicht spiegelbildlich, sondern identisch auszubilden. Beim schleifenförmigen Zusammenbiegen der Leiterplatte entstehen damit zwei Abschirmschichten, die bezüglich ihrer Anschlusspunkte die gleiche Biegerichtung aufweisen.In addition to the exemplary embodiment of the invention shown in FIGS. 1 and 2, there are a number of variants. One of these variants consists in forming the layers 52 and 56 of the flexible printed circuit board not in mirror image, but rather in an identical manner. When the circuit board is bent in a loop, two shielding layers are created which have the same bending direction with regard to their connection points.

Statt einer Schicht 54, die drei parallele Leiterzüge 82 bis 84 aufweist, kann eine Leiterschicht verwendet werden, die mehr oder weniger als drei Leiterzüge aufweist. Weiter können statt einer derartigen Schicht mehrere derartige Schichten übereinander angeordnet werden, wodurch Wicklungen mit mehr als drei Windungen herstellbar sind.Instead of a layer 54 which has three parallel conductor tracks 82 to 84, a conductor layer which has more or less than three conductor tracks can be used. Furthermore, instead of such a layer, a plurality of such layers can be arranged one above the other, as a result of which windings with more than three turns can be produced.

Statt einer Leiterplatte mit drei Metallschichten entsprechend Fig. kann eine zweischichtige Platte entsprechend Fig. 3 vorgesehen werden. Bei dieser sind die beispielsweise vier Leiterzüge 90 bis 93, die Anschlusspunkte an ihren beiden Enden aufweisen und zur Wicklungsherstellung dienen, auf der einen Plattenseite 94 angeordnet. Auf der andern Plattenseite befindet sich eine einzige grösserflächige Metallschicht 96. Durch Zusammenfalten der Platte parallel zu den Leiterzügen 90 bis 93 legt sich die eine Hälfte der Schicht 96 über diese Leiterzüge 90 bis 93, während die andere Hälfte auf der Unterseite verbleibt. Auf diese Weise entsteht eine aus gegeneinander isolierten Leiterzügen aufgebaute Einheit, die allseitig nach aussen abgeschirmt ist. Eine isolierende Deckschicht 97 bewirkt eine Isolierung nach aussen und ermöglicht eine Verschweissung am sonst offenen Faltende 98.Instead of a printed circuit board with three metal layers according to FIG. 3, a two-layer plate according to FIG. 3 can be provided. In this example, the four conductor tracks 90 to 93, which have connection points at their two ends and are used for winding production, are arranged on one side 94 of the plate. On the other side of the plate there is a single, larger-area metal layer 96. By folding the plate parallel to the conductor tracks 90 to 93, one half of the layer 96 is placed over these conductor tracks 90 to 93, while the other half remains on the underside. In this way, a unit is created which is made up of interconnects which are insulated from one another and which is shielded on all sides from the outside. An insulating cover layer 97 provides insulation from the outside and enables welding at the otherwise open fold end 98.

Ähnlich wie die oben beschriebene gefaltete Leiterplatte ist eine funktionsgleiche Einheit aufbaubar, bei der die Leiterzüge zur Bildung der Wicklung aus isolierten Drähten, beispielsweise Lackdrähten, bestehen. Fig. 4a zeigt eine Aufsicht auf diese versetzt parallel liegenden Drähte 101 bis 103, die auf der Ober- und Unterseite durch je eine eine Leiterschicht tragende Isolierschicht gehalten werden, so dass wiederum eine Einheit gegeben ist, bei der in der Mitte liegende Leiterzüge mit Anschlusspunkten an beiden Enden durch Abschirmschichten nach aussen abgeschirmt sind. Die Anschlusspunkte können entweder durch seitliches Herausführen der Drähte 101 bis 103 gebildet sein oder durch Bohrlöcher 104 bis 106, die so angebracht sind, dass jeweils ein Draht seitlich angebohrt und damit abisoliert ist. Die so gebildeten Löcher sind galvanisch durchplattierbar und entsprechen damit vollständig den Löchern 60 bis 67 von Fig. 2.Similar to the folded circuit board described above, a functionally identical unit can be constructed in which the conductor tracks for forming the winding consist of insulated wires, for example enamelled wires. 4a shows a top view of these staggered parallel wires 101 to 103, which are held on the top and bottom by an insulating layer each carrying a conductor layer, so that in turn there is a unit in which conductors lying in the middle with connection points are shielded from the outside by shielding layers at both ends. The connection points can either be formed by the wires 101 to 103 being led out to the side or by drill holes 104 to 106 which are provided in such a way that one wire is drilled to the side and thus stripped. The holes formed in this way can be plated through and thus correspond completely to the holes 60 to 67 of FIG. 2.

Fig. 4b zeigt eine derartige Einheit, die zu einer Schlaufe gebogen ist. Die herausstehenden Drähte 101 bis 103 sind mit ihren abisolierten Enden direkt in den Löchern 104 bis 106 verlötete. Die in Fig. 1 gezeigten Stifte 36 bis 39 bzw. 46 bis 49 erübrigen sich damit.Fig. 4b shows such a unit that is bent into a loop. The protruding wires 101 to 103 are soldered with their stripped ends directly in the holes 104 to 106. The pins 36 to 39 and 46 to 49 shown in FIG. 1 are therefore unnecessary.

Statt eines einzigen geschlossenen Ferritringes 30 können als Übertragerkern zwei oder mehr koaxial nebeneinander angeordnete Ferritkerne 30.1, 30.2, 30.3 dienen, durch deren Öffnungen die flexiblen Leiterplatten 31 und 32 hindurchgehen (Fig. 6).Instead of a single closed ferrite ring 30, two or more ferrite cores 30.1, 30.2, 30.3 arranged coaxially next to one another can serve as the transformer core, through whose openings the flexible printed circuit boards 31 and 32 pass (FIG. 6).

Das Koaxialkabel 20 kann ausschliesslich mechanisch an der tragenden Leiterplatte 11 befestigt und dessen Mittelleiter 21 direkt mit dem Wicklungsanfang der flexiblen Leiterplatte 31 verbunden sein.The coaxial cable 20 can only be mechanically fastened to the supporting printed circuit board 11 and its central conductor 21 can be connected directly to the start of the winding of the flexible printed circuit board 31.

Damit eine gute Spannungsfestigkeit gegenüber höheren Spannungen gewährleistet wird, können die Abschirmschichten 52 und 56 der flexiblen Leiterplatte in der Mitte hantelförmig verengt sein, um an den Biegestellen verbesserte Isolierfähigkeit der Isolierschichten-Verschweissung zu bekommen.In order to ensure a good dielectric strength against higher voltages, the shielding layers 52 and 56 of the flexible printed circuit board can be narrowed in the shape of a dumbbell in the middle in order to obtain improved insulating ability of the insulating layer welding at the bending points.

Statt den Ferritkern schleifenförmig zu durchsetzen, können die flexiblen Leiterplatten 31 und 32 den Kern auch leicht bogenförmig entsprechend Fig. 5 durchsetzen. In diesem Fall ist beispielsweise die flexible Leiterplatte 89 auf beiden Seiten des Ringkerns 30 mit Stiften 191 bis 198 auf einer tragenden Leiterplatte 11 elektrisch und mechanisch befestigt. Die Leiterzüge entsprechend 82, 83 und 84 von Fig. 2 können dabei entweder durch Leiterzüge 90 auf der tragenden Leiterplatte 11 oder durch eine zweite flexible Leiterplatte, die den Ringkern 30 nicht durchsetzt, ergänzt sein.Instead of pushing through the ferrite core in a loop, the flexible printed circuit boards 31 and 32 can also push through the core in a slightly arcuate manner as shown in FIG. 5. In this case, for example, the flexible printed circuit board 89 is fixed electrically and mechanically on both sides of the toroidal core 30 with pins 191 to 198 on a supporting printed circuit board 11. The conductor tracks corresponding to 82, 83 and 84 of FIG. 2 can either be supplemented by conductor tracks 90 on the supporting printed circuit board 11 or by a second flexible printed circuit board which does not penetrate the toroidal core 30.

Fig. 6 zeigt schliesslich schematisch eine Halterung 110 für einen vollständigen Impulsübertrager, der sich aus drei koaxial übereinanderliegenden, nahtlosen Ferritkernen 30.1, 30.2 und 30.3 und zwei schleifenförmig gebogenen Wicklungseinheiten, beispielsweise Leiterplatten 31 und 32 der anhand von Fig. 2 beschriebenen Art, zusammensetzt. Die Stifte 112 und 113 der rechten Einheit verbinden in der beschriebenen Artdie die Wicklung bildenden Leiterzüge und fixieren die Einheit an der Halterung. Die restlichen Stifte 111 und 114 sind aus der Halterung 110 herausgeführt und dienen als Lötstift zum Verbinden mit der Trägerleiterplatte 11. Die Wicklungseinheit zeigt eine Verlängerung 115, die eine mit den Abschirmschichten der flexiblen Leiterplatte 31 elektrisch verbundene zusätzliche Abschirmschicht aufweist. Diese Verlängerung 115 ist laschenförmig über die Stiftoberenden gebogen und schirmt diese elektrisch ab. Unten übernimmt die Schicht 14 der Trägerleiterplatte 11 die entsprechende Funktion. Hierdurch wird eine weitere Verbesserung der Abschirmeigenschaften erreicht. Für die zweite Wicklungseinheit 32 gilt Entsprechendes.Finally, FIG. 6 shows schematically a holder 110 for a complete pulse transmitter, which is composed of three seamless ferrite cores 30.1, 30.2 and 30.3 which are coaxially one above the other and two loop-shaped winding units, for example printed circuit boards 31 and 32 of the type described with reference to FIG. 2. The pins 112 and 113 of the right unit connect the conductor tracks forming the winding in the manner described and fix the unit to the holder. The remaining pins 111 and 114 are led out of the holder 110 and serve as a soldering pin for connection to the carrier circuit board 11. The winding unit shows an extension 115 which has an additional shielding layer electrically connected to the shielding layers of the flexible circuit board 31. This extension 115 is bent in a lug shape over the pin ends and shields them electrically. At the bottom, the layer 14 of the carrier circuit board 11 takes over the corresponding function. This further improves the shielding properties. The same applies to the second winding unit 32.

Der Windungssinn der Schleifen der zwei Wicklungseinheiten eines Impulsübertragers kann natürlich entsprechend Fig. gleichsinnig oder in etwas geänderter Geometrie auch gegensinnig sein.The winding sense of the loops of the two winding units of a pulse transformer can be na of course in the same direction according to Fig. or in slightly changed geometry also in opposite directions.

Impulsübertrager der beschriebenen Art werden beispielsweise verwendet als Trennübertrager zwischen einer elektronischen Schaltungsanordnung und einer Übertragungsleitung zur Übertragung schneller digitaler Signale. Die Übertragungsleitung kann dabei wie in Fig. 1 gezeigt, als Koaxialkabel 20 oder als anderes, für Digitalsignale geeignetes Kabel, beispielsweise eine aus zwei Aderpaaren bestehende Vierdrahtleitung, ausgebildet sein. Auf dieser kann zusätzlich zu den digitalen Signalen in an sich bekannter Weise ein Speisestrom fliessen.Pulse transformers of the type described are used, for example, as isolating transformers between an electronic circuit arrangement and a transmission line for the transmission of fast digital signals. The transmission line can, as shown in FIG. 1, be designed as a coaxial cable 20 or as another cable suitable for digital signals, for example a four-wire line consisting of two wire pairs. In addition to the digital signals, a feed current can flow on this in a manner known per se.

Claims (17)

1. An impulse transformer comprising an annular seamlessly-closed core (30) and having primary and secondary windings, such that there is provided at least one plate-shaped carrier (31, 32) made from insulating material which carries series of conductors (82...84, 90...93, 101...103) which are mutually electrically insulated and which lie side-by-side, in that each series of conductors (82...84, 90...93, 101...103) is elongate and has connection points (75...81, 104...106) at its two ends, in that each carrier (31, 32) together with its series of conductors (82...84, 90...93, 101...103) extends through the core (30), and in that the series'of conductors (82...84, 90...93, 101...103) of each carrier are so connected together electrically outside the core (30) by way of their two connection points (75...81, 104...106) that they thereby become turns of the windings, characterised in that shielding conductors (52, 56, 96) are provided which each have a single connection point (70, 88) and which are of larger area than the series of conductors (82...84, 90...93, 101...103), and in that each carrier (31, 32) has layers (51, 53, 55, 57, 97) of insulating material, between which lie a series of layers (54) of conductors (82...84, 90...93, 101...103) and layers of shielding conductors (52, 56, 96), such that the layers (51, 53, 55, 57, 97) and layers (54) are connected together mechanically and form altogether a flexible unit (31, 32), and in that the shielding conductors (52, 56, 96) are so arranged that they cover the series of conductors (82...84, 90...93, 101...103) outwardly as to the predominant part thereof and thus shield them electrically.
2. An impulse transformer according to claim 1, characterised in that flexible carriers (31, 32) which are independent of one another are provided for the primary winding and for the secondary winding (Figs. 1 and 6).
3. An impulse transformer according to claims 1 and 2, characterised in that the carrier, the series of conductors (82...84, 90...93) and the shielding conductors (52, 56, 96) are designed as a band-shaped flexible multi-layer printed circuit board (31, 32) (Figs. 2 and 3).
4. An impulse transformer according to claims 1 to 3, characterised in that the flexible printed circuit board (31, 32) has three conductor layers, in that the central conductor layer (54) has at least two series of conductors (82...84) which lie substantially parallel and the connection points (75...81) of which are arranged one behind the other in the longitudinal direction, in that the two outer conductor layers each have a shielding conductor (52, 56), and in that these shielding conductors (52, 56) have cutouts (71, 72, 86, 87) which are so arranged that the connection points (75...81) of the series of conductors (82...84) are uncovered (Fig. 2).
5. An impulse transformer according to claims 1 to 3, characterised in that the flexible printed circuit board (31, 32) has two conductor layers, in that the one of these layers has at least one series of conductors (90...93) and the other conductor layer has a shielding conductor (96), and in that the flexible printed circuit board (31, 32) is folded together parallel to its longitudinal direction in such a way that the series of conductors (90...93) are covered substantially on all sides by the shielding conductor (96) (Fig. 3).
6. An impulse transformer according to claims 1 and 2, characterised in that the carrier and the shielding conductor are a single-layer folded flexible printed circuit board (31, 32) which has, in its inner region which has arisen as a result of the folding, parallellying insulating wire pieces (101...103), the one ends of which are conducted out outwardly.
7. An impulse transformer according to claims 1 to 4, characterised in that the connection points (70, 88) of the shielding conductors (52, 56) are arranged at the same end of the printed circuit board.
8. An impulse transformer according to claims 1 to 4, characterised in that the connection points (70, 88) of the shielding conductors (52, 56) are arranged so as to be distributed at the two ends of the flexible printed circuit board (Fig. 2).
9. An impulse transformer according to claims 1 to 6, characterised in that two carriers together with their series of conductors (82...84, 90...93, 101...103) extend through the core (30), are bent together in a loop-shaped manner and the connection points (75...81, 104...106) of the series of conductors (82...84, 90...93, 101...103) of each flexible carrier (31, 32) are electrically connected to one another in pairs (Figs. 1 and 6).
10. An impulse transformer according to claim 9, characterised in that the connection points (75...81) are connected by means of pins (36...39,
46...49), among themselves and are connectable to other conductors (15) (Fig. 1).
11. An impulse transformer according to claims 1 to 10, characterised in that one layer of the flexible carrier has an extension (115) which carries a shielding conductor and in that this extension (115) is bent in a strap-shaped or fish-plate-shaped manner over the upper ends of the pins (111-114) (Fig. 6).
12. An impulse transformer according to claims 1 to 6, characterised in that two flexible carriers (31, 32) together with their series of conductors (82...84, 90...93, 101...103) penetrate the core (30) in an arcuate manner, and in that a carrying printed circuit board (11) is provided, to the conductors (90) of which the series of conductors (82...84, 90...93, 101...103) are electrically connected by means of pins (191-198) (Fig. 5).
13. An impulse transformer according to claim 1, characterised in that the core (30) is composed of three independent coaxially-arranged ferrite cores (30.1...30.3) (Fig. 6).
14. Use of the impulse transformer according to one of the preceding claims as an isolating transformer between an electronic circuit arrangement and a line for the transmission of digital signals.
15. Arrangement of the impulse transformer according to one of claims 1 to 13 upon use as an isolating transformer according to claim 14, characterised in that a three-layer carrying printed circuit board (11) is provided for the fastening of the impulse transformer and of the end of a coaxial cable (20) as line, in that, at the location at which the impulse transformer is arranged, between the conductors (13, 43, 14, 44) of the outer printed circuit board layers are present nonconducting regions (41, 42) separating these layers, in that the one conductors (13, 14) of the outer printed circuit board layers are electrically connected by the shielding of the coaxial cable (20), and by the shielding conductors (52, 56, 96) only to the one end (81) of the one coil (31), and in that a series of conductors (15) of the central printed circuit board layer is electrically connected to the central conductor (21) and the other end (77) of the one coil (31).
16. Arrangement according to claim 15, characterised in that the one series of conductors (15) of the central printed circuit board layer is so designed in its width that, together with the distance between the layers (13, 15, 14) as well as with the electrical properties of the insulating material (12), a wave or characteristic resistance (impedance) arises which corresponds to that of the coaxial cable (20).
EP81100159A 1980-02-01 1981-01-12 Pulse transformer and its use as isolation transformer Expired EP0033441B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT81100159T ATE9419T1 (en) 1980-02-01 1981-01-12 PULSE TRANSMITTER AND ITS USE AS ISOLATION TRANSMITTER.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH81480 1980-02-01
CH814/80 1980-02-01

Publications (2)

Publication Number Publication Date
EP0033441A1 EP0033441A1 (en) 1981-08-12
EP0033441B1 true EP0033441B1 (en) 1984-09-12

Family

ID=4195809

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81100159A Expired EP0033441B1 (en) 1980-02-01 1981-01-12 Pulse transformer and its use as isolation transformer

Country Status (6)

Country Link
US (1) US4342976A (en)
EP (1) EP0033441B1 (en)
JP (1) JPS56129305A (en)
AT (1) ATE9419T1 (en)
CA (1) CA1144247A (en)
DE (1) DE3165884D1 (en)

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Also Published As

Publication number Publication date
JPS56129305A (en) 1981-10-09
JPS6335089B2 (en) 1988-07-13
US4342976A (en) 1982-08-03
CA1144247A (en) 1983-04-05
DE3165884D1 (en) 1984-10-18
EP0033441A1 (en) 1981-08-12
ATE9419T1 (en) 1984-09-15

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