WO1990014707A1 - Electrical device with transient protection - Google Patents

Electrical device with transient protection Download PDF

Info

Publication number
WO1990014707A1
WO1990014707A1 PCT/GB1990/000824 GB9000824W WO9014707A1 WO 1990014707 A1 WO1990014707 A1 WO 1990014707A1 GB 9000824 W GB9000824 W GB 9000824W WO 9014707 A1 WO9014707 A1 WO 9014707A1
Authority
WO
WIPO (PCT)
Prior art keywords
component
foldback
devices
lines
electrical
Prior art date
Application number
PCT/GB1990/000824
Other languages
French (fr)
Inventor
David Mansel Williams
David Crofts
Original Assignee
Raychem Limited
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority claimed from GB898912144A external-priority patent/GB8912144D0/en
Priority claimed from GB909002174A external-priority patent/GB9002174D0/en
Application filed by Raychem Limited filed Critical Raychem Limited
Publication of WO1990014707A1 publication Critical patent/WO1990014707A1/en

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
    • H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
    • H02H9/044—Physical layout, materials not provided for elsewhere

Definitions

  • This invention relates to electrical devices or com ⁇ ponents that are protected from electrical transients.
  • Electromagnetic pulses can induce very high currents and voltages on cables and structures such as aeroplanes and ships, which can penetrate the electrical systems and damage them, either causing hardware damage such as semiconductor burnout, or electronic upset, e.g. transition loss or loss of stored data. As semiconductor technology advances, the energy needed to cause such damage becomes smaller.
  • Electrostatic discharges are extremely fast discharges from a capacitor such as a human body. These discharges, becuase they can be so local, present an extreme threat to the individual electronic component.
  • the magnitude of the threat is illustrated by reference to IEC Technical Committee TC65, WG4 draft specification or the SAE-AE-4 pro ⁇ posed specification on ESD.
  • the maximum threat is a double exponential pulse of rise time 5 nanose ⁇ conds with a 30 nanosecond fall time.
  • the peak voltage is given as 15,000 volts with a current of 70 amps.
  • the energy storage capacitance is given as 150 pico farads giving a maximum energy of 33 millijoules.
  • the characteristics of the induced pulses are best described in the SAE AE4 Committee Report AE4L-81-22.
  • Test Wave Forms and Techniques for Assessing the Effects of Lightning-Induced Transients This specifi ⁇ cation describes the idealised versions of the lightning stroke waveform and of those which occur when equipment cables are excited by the EM environment produced.
  • the spe ⁇ cification specified a range of transients which may be pro ⁇ quizzed during normal operation.
  • the waveforms expected on each line depends of a number of factors but the two basic types are (waveform 3) with a frequency of between 1 and 0 MHz, a rise time of 45 nanoseconds and a peak current of 24 amps.
  • the alternative wave form (Wave Form 4A) is a decaying exponential with a rise time of 100 nanoseconds and a width of 2 microseconds with a peak voltage of 300 volts and peak .current of 60 amps.
  • the most severe threat to electrical and electronic equipment is the electromagnetic pulse due to detonation of a nuclear device which can generate large voltage or current spikes with very short rise times.
  • the exact charac ⁇ teristics of the pulse are complicated although a typical pulse will exhibit a field strength of about 10 5 Vm -1 with an accompanying H field intensity of 270 Am -1 (based on free space impedance of 377 ohms), a pulse width of a few microseconds and a rise time of a few nanoseconds.
  • damaging amplitudes in the pulse occur within the frequency range of lOKHz to 100MHz.
  • Def Stan 59-41 part 3 issue 3 uses a test for imported transient susceptibility in aircraft that employs transients of up to 30 MHz with a peak voltage of 500 V, which corresponds to a maximum voltage rise in the order of 15kVus _1 .
  • an electrical component that has a generally flat con ⁇ figuration and has an array of electrical lines which extend through the component, and which includes a ground element, at least some of the lines being protected against a voltage transient by means of a circuit protection device that is connected between the line and the ground element and is arranged to short a transient in the line to the ground ele ⁇ ment, the circuit protection devices comprising a single crystal semiconductor foldback device.
  • foldback device is particularly suited for use in a flat component in view of its generally planar geometry and its size.
  • the foldback devices may, for example, be mounted directly on the electrical lines of the component or the housing thereof or any internal part that holds the electrical lines, and are preferably mounted in the component in the absence of any additional heat sinks.
  • the lateral dimensions of the device may be arranged to correspond approximately to the spacing of the electrical lines so that the arrangement of the devices within the com ⁇ ponent is relatively straightforward.
  • the foldback devices are preferably multilayer devices, e.g. junction effect devices.
  • One particularly preferred form of device that may be employed is a silicon controlled rectifier, for example one in the form of a PNPN junction device.
  • Such devices which may be manufactured in monolithic form by conventional ion implantation techniques, may be, and advantageously are, formed as a bidirectional device in which in one part of the device the order of the layers is reversed so that the device will switch to its low resistance state when subjected to a pulse of either polarity.
  • the construction of the component in accordance with the inven- tion can enable the switching device to switch without an undue overvoltage when subjected to considerably faster pulses.
  • switches that are intended to operate with pulses having a rate of rise of up to 5 kVus -1 can operate with pulses up to lOkVus -1 or even higher.
  • the component normally comprises an electrical connec ⁇ tor which includes a housing and one or more generally flat inserts that have a plurality of electrically conductive lines extending through or on it from one end to the other, the lines being connectable at one end to a cable or har ⁇ ness, and terminating at their other end at a contact, e.g. a pin, tuning-fork or other contact.
  • the flat insert or "wafer” preferably includes a transversely extending conductive path that is in electri ⁇ cal contact with the ground element, the transverse path being connected to each of the foldback devices.
  • the devices may have both electrical contacts on the same side thereof and be positioned so that they overlie, and are in contact with, a line of the connector and the transverse path.
  • the devices may have electrical contacts on opposite sides thereof, they may be positioned on the lines of the conductor and wire bonded to the transverse path or vice versa.
  • the com ⁇ ponent comprises a generally flat body having the lines extending therethrough in the plane of the body, the body having a cavity therein such that part of the lines are exposed, the cavity defining at least one internal shoulder that has a transversely extending conductive path and which accommodates a plurality of the circuit protection devices, each circuit protection device being connected between one of the lines and the conductive path being connected to the ground element.
  • This form of device may have the lines extending out from the flat body in the plane of the body in the form of pins or sockets, or the lines on one or both sides may be bent through 90° in order to enable connections to be made by means of contacts on a board.
  • the electrical connections to the lines may be made in any suitable manner, but it is preferred to employ a generally flat heat-shrinkable connec ⁇ tor device that is divided into a plurality of heat- shrinkable channels, each of which contains a quantity of solder for forming a solder connection between one of the lines and a conductor of a flat cable.
  • the component body is preferably formed from a plastics material, and especially a ther oset such as an epoxy, the body being built up from a number of laminae of the thermoset.
  • Such devices which may be manufactured in monolithic form by conventional ion implantation techniques, may be, and advantageously are, formed as a bidirectional device in which in one part of the device the order of the layers is reversed so that the device will switch to its low resistance state when subjected to a pulse of either polarity.
  • the component normally comprises an electrical connec ⁇ tor which includes a housing and one or more generally flat inserts that have a plurality of electrically conductive lines extending through or on it from one end to the other, the lines being connectable at one end to a cable or har ⁇ ness, and terminating at their other end at a contact, e.g.
  • the flat insert or "wafer” preferably includes a transversely extending conductive path that is in electri ⁇ cal contact with the ground element, the transverse path being connected to each of the foldback devices.
  • the devices may have both electrical contacts on the same side thereof and be positioned so that they overlie, .and are in contact with, a line of the connector and the transverse path.
  • the devices may have electrical contacts on opposite sides thereof, they may be positioned on the lines of the conductor and wire bonded to the transverse path or vice versa.
  • the com ⁇ ponent comprises a generally flat body having the lines extending therethrough in the plane of the body, the body having a cavity therein such that part of the lines are exposed, the cavity defining at least one internal shoulder that has a transversely extending conductive path and which accommodates a plurality of the circuit protection devices, each circuit protection device being connected between one of the lines and the conductive path being connected to the ground element.
  • This form of device may have the lines extending out from the flat body in the plane of the body in the form of pins or sockets, or the lines on one or both sides may be bent through 90° in order to enable connections to be made by means of contacts on a board.
  • the electrical connections to the lines may be made in any suitable manner, but it is preferred to employ a generally flat heat-shrinkable connec ⁇ tor device that is divided into a plurality of heat- shrinkable channels, each of which contains a quantity of solder for forming a solder connection between one of the lines and a conductor of a flat cable.
  • the component body is preferably formed from a plastics material, and especially a thermoset such as an epoxy, the body being built up from a number of laminae of the thermoset.
  • Figure 1 is a top plan view of part of one form of electrical component according to the invention.
  • Figure 2 is a side section through part of the com ⁇ ponent of figure 1;
  • Figure 3 is a top plan view, partly in section, of another form of component according to the invention.
  • Figure 4 is a side sectional view of the component of figure 3 with the thickness thereof exaggerated for the sake of clarity.
  • a plastics wafer 1 intended to be inserted into a flat electrical con ⁇ nector as described in US Patent No: 3,993,394, the disclo ⁇ sure of which is incorporated herein by reference, encloses a number of lines 2, which terminate at one end 3 in the form of contacts, for example pins as shown or tuning fork - p _
  • one line 2' located at one end of the array of lines is intended to be connected to earth.
  • a transversely extending recess 4 has been cut out of the wafer material (either by milling or, more usually, by being moulded in the appropriate shape) to expose parts of the lines 2.
  • a transversely extending metal path 5 is provided on the wafer adjacent to the cut-out recess, and optionally in a stepped portion as shown.
  • a number of flat circuit protection elements 6 are each located on the exposed parts of different lines 2.
  • the ele ⁇ ments are formed by ion implantion of a silicon wafer to form a bidirectional PNPN junction device.
  • the upper and lower surfaces of each device are each provided with a depo ⁇ sited metal electrode, and the elements are bonded to the lines by means of solder (not shown) .
  • a conventional wire bond 7 is used to form a connection between the upper electrode of the elements 6 and the transverse path 5, and a further wire bond 7' connects the transverse path 5 with the end line 2' forming the earth line.
  • the wafer After termination of a cable or wire bundle to the rearward end of the wafer, the wafer, or a pair of such wafers, can be simply inserted into a flat connector housing of the type described in US Patent No. 3,993,394 mentioned above to form a connector-terminated and EMP protected cable.
  • a splice component for a pair of flat cables 31 comprises flat, rigid, epoxy body 32 which has a cavity 33 therein.
  • the body 31 has a number of electrical conductors 34 extending through it, part 35 of the conductors being exposed within the cavity.
  • the cavity has a pair of shoulders 36 adjacent to the exposed electri- cal conductors, on which a laterally extending conductive track or "ground plane" 37 is formed.
  • a number of flat cir ⁇ cuit protection elements 38 of the type described with reference to figures l and 2 are located on each of the shoulders 36 so that they are in electrical contact with the ground plane 37.
  • Each device is connected to one of the exposed electrical conductors 34 by means of wire bonds 39.
  • the end conductor 34a is maintained at ground potential, and the end of the ground planes 37 are connected to the ground conductor 34a also by means of a wire bond 40.
  • the device may be provided with a conductor on its base for grounding to a frame or chassis, in which case a through hole 41 is used to provide an electrical connection to the base conductor.
  • An epoxy lid (not shown) is provided to enclose the circuit protection elements 38 and exposed conductors 34.
  • the conductors 34 may be connected to other electrical components by any appropriate means. For example they may be bent downwardly for insertion into an appropriate connec ⁇ tor. Alternatively the component may be connected t a flat cable or a bundle of primary wires by means of a flat heat- recoverable multiple solder connector, for example and pre ⁇ ferably one of the type shown in figure 8 of US Patent No. 3,852,517 to Del Fava employing the conductive inserts shown in figures 10 and 11 thereof. The disclosure of this reference is incorporated herein by reference.

Abstract

An electrical component has a generally flat configuration and an array of electrical lines (2, 34) extending through it and includes a ground element (2, 34a). At least some of the lines are protected by means of circuit protection devices (6, 38) connected between the lines and the ground element. The circuit protection devices comprise single crystal semiconductor foldback devices, e.g. a PNPN junction effect device. Preferably the devices are located on the lines (2) and are connected to a transversely extending conductive path (5) by means of wire bonds (7) or they may be located on the transverse path and be wire bonded to the conductors (34).

Description

- I -
Electrical Device with Transient Protection
This invention relates to electrical devices or com¬ ponents that are protected from electrical transients.
Electromagnetic pulses can induce very high currents and voltages on cables and structures such as aeroplanes and ships, which can penetrate the electrical systems and damage them, either causing hardware damage such as semiconductor burnout, or electronic upset, e.g. transition loss or loss of stored data. As semiconductor technology advances, the energy needed to cause such damage becomes smaller.
Electrostatic discharges are extremely fast discharges from a capacitor such as a human body. These discharges, becuase they can be so local, present an extreme threat to the individual electronic component. The magnitude of the threat is illustrated by reference to IEC Technical Committee TC65, WG4 draft specification or the SAE-AE-4 pro¬ posed specification on ESD. In these documents the maximum threat is a double exponential pulse of rise time 5 nanose¬ conds with a 30 nanosecond fall time. The peak voltage is given as 15,000 volts with a current of 70 amps. The energy storage capacitance is given as 150 pico farads giving a maximum energy of 33 millijoules.
Induced electrical transients caused by lightning repre¬ sent a threat to electrical/electronic equipment especially in aerospace vehicles. The characteristics of the induced pulses are best described in the SAE AE4 Committee Report AE4L-81-22. Test Wave Forms and Techniques for Assessing the Effects of Lightning-Induced Transients. This specifi¬ cation describes the idealised versions of the lightning stroke waveform and of those which occur when equipment cables are excited by the EM environment produced. The spe¬ cification specified a range of transients which may be pro¬ duced during normal operation. The waveforms expected on each line depends of a number of factors but the two basic types are (waveform 3) with a frequency of between 1 and 0 MHz, a rise time of 45 nanoseconds and a peak current of 24 amps. The alternative wave form (Wave Form 4A) is a decaying exponential with a rise time of 100 nanoseconds and a width of 2 microseconds with a peak voltage of 300 volts and peak .current of 60 amps.
The most severe threat to electrical and electronic equipment is the electromagnetic pulse due to detonation of a nuclear device which can generate large voltage or current spikes with very short rise times. The exact charac¬ teristics of the pulse are complicated although a typical pulse will exhibit a field strength of about 10 5 Vm-1 with an accompanying H field intensity of 270 Am-1 (based on free space impedance of 377 ohms), a pulse width of a few microseconds and a rise time of a few nanoseconds. In general damaging amplitudes in the pulse occur within the frequency range of lOKHz to 100MHz. For example, Def Stan 59-41 part 3 issue 3 uses a test for imported transient susceptibility in aircraft that employs transients of up to 30 MHz with a peak voltage of 500 V, which corresponds to a maximum voltage rise in the order of 15kVus_1.
According to the present invention, there is provided an electrical component that has a generally flat con¬ figuration and has an array of electrical lines which extend through the component, and which includes a ground element, at least some of the lines being protected against a voltage transient by means of a circuit protection device that is connected between the line and the ground element and is arranged to short a transient in the line to the ground ele¬ ment, the circuit protection devices comprising a single crystal semiconductor foldback device.
This form of foldback device is particularly suited for use in a flat component in view of its generally planar geometry and its size. The foldback devices may, for example, be mounted directly on the electrical lines of the component or the housing thereof or any internal part that holds the electrical lines, and are preferably mounted in the component in the absence of any additional heat sinks. The lateral dimensions of the device may be arranged to correspond approximately to the spacing of the electrical lines so that the arrangement of the devices within the com¬ ponent is relatively straightforward.
The foldback devices are preferably multilayer devices, e.g. junction effect devices. One particularly preferred form of device that may be employed is a silicon controlled rectifier, for example one in the form of a PNPN junction device.
Such devices, which may be manufactured in monolithic form by conventional ion implantation techniques, may be, and advantageously are, formed as a bidirectional device in which in one part of the device the order of the layers is reversed so that the device will switch to its low resistance state when subjected to a pulse of either polarity.
We have found that at least in some cases, the construction of the component in accordance with the inven- tion can enable the switching device to switch without an undue overvoltage when subjected to considerably faster pulses. Thus, we have found that switches that are intended to operate with pulses having a rate of rise of up to 5 kVus-1 can operate with pulses up to lOkVus-1 or even higher.
The component normally comprises an electrical connec¬ tor which includes a housing and one or more generally flat inserts that have a plurality of electrically conductive lines extending through or on it from one end to the other, the lines being connectable at one end to a cable or har¬ ness, and terminating at their other end at a contact, e.g. a pin, tuning-fork or other contact. In this preferred form of connector the flat insert or "wafer" preferably includes a transversely extending conductive path that is in electri¬ cal contact with the ground element, the transverse path being connected to each of the foldback devices. For example, the devices may have both electrical contacts on the same side thereof and be positioned so that they overlie, and are in contact with, a line of the connector and the transverse path. Alternatively, if for example, the devices have electrical contacts on opposite sides thereof, they may be positioned on the lines of the conductor and wire bonded to the transverse path or vice versa.
In another preferred aspect of the invention the com¬ ponent comprises a generally flat body having the lines extending therethrough in the plane of the body, the body having a cavity therein such that part of the lines are exposed, the cavity defining at least one internal shoulder that has a transversely extending conductive path and which accommodates a plurality of the circuit protection devices, each circuit protection device being connected between one of the lines and the conductive path being connected to the ground element.
This form of device may have the lines extending out from the flat body in the plane of the body in the form of pins or sockets, or the lines on one or both sides may be bent through 90° in order to enable connections to be made by means of contacts on a board. The electrical connections to the lines may be made in any suitable manner, but it is preferred to employ a generally flat heat-shrinkable connec¬ tor device that is divided into a plurality of heat- shrinkable channels, each of which contains a quantity of solder for forming a solder connection between one of the lines and a conductor of a flat cable.
The component body is preferably formed from a plastics material, and especially a ther oset such as an epoxy, the body being built up from a number of laminae of the thermoset.
Such devices, which may be manufactured in monolithic form by conventional ion implantation techniques, may be, and advantageously are, formed as a bidirectional device in which in one part of the device the order of the layers is reversed so that the device will switch to its low resistance state when subjected to a pulse of either polarity.
We have found that at least in some cases, the construction of the component in accordance with the inven¬ tion can enable the switching device to switch without an undue overvoltage when subjected to considerably faster pulses. Thus, we have found that switches that are intended to operate with pulses having a rate of rise of up to 5 kvus-1 can operate with pulses up to lOkVus-1 or even higher. The component normally comprises an electrical connec¬ tor which includes a housing and one or more generally flat inserts that have a plurality of electrically conductive lines extending through or on it from one end to the other, the lines being connectable at one end to a cable or har¬ ness, and terminating at their other end at a contact, e.g. a pin, tuning-fork or other contact. In this preferred form of connector the flat insert or "wafer" preferably includes a transversely extending conductive path that is in electri¬ cal contact with the ground element, the transverse path being connected to each of the foldback devices. For example, the devices may have both electrical contacts on the same side thereof and be positioned so that they overlie, .and are in contact with, a line of the connector and the transverse path. Alternatively, if for example, the devices have electrical contacts on opposite sides thereof, they may be positioned on the lines of the conductor and wire bonded to the transverse path or vice versa.
In another preferred aspect of the invention the com¬ ponent comprises a generally flat body having the lines extending therethrough in the plane of the body, the body having a cavity therein such that part of the lines are exposed, the cavity defining at least one internal shoulder that has a transversely extending conductive path and which accommodates a plurality of the circuit protection devices, each circuit protection device being connected between one of the lines and the conductive path being connected to the ground element.
This form of device may have the lines extending out from the flat body in the plane of the body in the form of pins or sockets, or the lines on one or both sides may be bent through 90° in order to enable connections to be made by means of contacts on a board. The electrical connections to the lines may be made in any suitable manner, but it is preferred to employ a generally flat heat-shrinkable connec¬ tor device that is divided into a plurality of heat- shrinkable channels, each of which contains a quantity of solder for forming a solder connection between one of the lines and a conductor of a flat cable.
The component body is preferably formed from a plastics material, and especially a thermoset such as an epoxy, the body being built up from a number of laminae of the thermoset.
One form of device will now be described by way of example with reference to the accompanying drawings, in which:
Figure 1 is a top plan view of part of one form of electrical component according to the invention;
Figure 2 is a side section through part of the com¬ ponent of figure 1;
Figure 3 is a top plan view, partly in section, of another form of component according to the invention; and
Figure 4 is a side sectional view of the component of figure 3 with the thickness thereof exaggerated for the sake of clarity.
Referring to the accompanying drawings, a plastics wafer 1 intended to be inserted into a flat electrical con¬ nector as described in US Patent No: 3,993,394, the disclo¬ sure of which is incorporated herein by reference, encloses a number of lines 2, which terminate at one end 3 in the form of contacts, for example pins as shown or tuning fork - p _
contacts. In this form of connector, one line 2' located at one end of the array of lines is intended to be connected to earth.
A transversely extending recess 4 has been cut out of the wafer material (either by milling or, more usually, by being moulded in the appropriate shape) to expose parts of the lines 2. In addition, a transversely extending metal path 5 is provided on the wafer adjacent to the cut-out recess, and optionally in a stepped portion as shown. A number of flat circuit protection elements 6 are each located on the exposed parts of different lines 2. The ele¬ ments are formed by ion implantion of a silicon wafer to form a bidirectional PNPN junction device. The upper and lower surfaces of each device are each provided with a depo¬ sited metal electrode, and the elements are bonded to the lines by means of solder (not shown) . A conventional wire bond 7 is used to form a connection between the upper electrode of the elements 6 and the transverse path 5, and a further wire bond 7' connects the transverse path 5 with the end line 2' forming the earth line.
After termination of a cable or wire bundle to the rearward end of the wafer, the wafer, or a pair of such wafers, can be simply inserted into a flat connector housing of the type described in US Patent No. 3,993,394 mentioned above to form a connector-terminated and EMP protected cable.
Referring to figure 3 and 4 a splice component for a pair of flat cables 31 comprises flat, rigid, epoxy body 32 which has a cavity 33 therein. The body 31 has a number of electrical conductors 34 extending through it, part 35 of the conductors being exposed within the cavity. The cavity has a pair of shoulders 36 adjacent to the exposed electri- cal conductors, on which a laterally extending conductive track or "ground plane" 37 is formed. A number of flat cir¬ cuit protection elements 38 of the type described with reference to figures l and 2 are located on each of the shoulders 36 so that they are in electrical contact with the ground plane 37. Each device is connected to one of the exposed electrical conductors 34 by means of wire bonds 39. In the component shown the end conductor 34a is maintained at ground potential, and the end of the ground planes 37 are connected to the ground conductor 34a also by means of a wire bond 40. In addition, the device may be provided with a conductor on its base for grounding to a frame or chassis, in which case a through hole 41 is used to provide an electrical connection to the base conductor. An epoxy lid (not shown) is provided to enclose the circuit protection elements 38 and exposed conductors 34.
The conductors 34 may be connected to other electrical components by any appropriate means. For example they may be bent downwardly for insertion into an appropriate connec¬ tor. Alternatively the component may be connected t a flat cable or a bundle of primary wires by means of a flat heat- recoverable multiple solder connector, for example and pre¬ ferably one of the type shown in figure 8 of US Patent No. 3,852,517 to Del Fava employing the conductive inserts shown in figures 10 and 11 thereof. The disclosure of this reference is incorporated herein by reference.

Claims

Claims
1. An electrical component that has a generally flat con¬ figuration and has an array of electrical lines which extend through the connector, and which includes a ground element, at least some of the lines being protected against a voltage transient by means of a circuit protection device that is connected between the line and the ground element and is arranged to short a transient in the line to the ground ele¬ ment, the circuit protection devices comprising a single crystal semiconductor foldback device.
2. A component as claimed in claim 1, wherein the or each semiconductor foldback device is a multilayer device.
3. A component as claimed in claim 2 wherein the foldback device is a junction effect device.
4. A component as claimed in any one of claims 1 to 3, wherein the foldback device is a silicon controlled rec¬ tifier.
5. A component as claimed in claim 4, wherein the foldback device comprises a PNPN junction device.
6. A component as claimed in any one of claims l to 5, wherein the foldback device has a holding current of at least 50 mA, preferably at least 100 mA.
7. A component as claimed in any one of claims l to 6, which includes a housing and one or more generally flat inserts that can be located within the housing, the or each insert carrying the electrical lines and the foldback devi¬ ces.
8. A component as claimed in any one of claims l to 7, which includes a transversely oriented conductive path to which the foldback devices are connected, and which is con¬ nected to the ground elements.
9. A component as claimed in claim 7, wherein the or each insert has a recess that exposes part of the electrical lines, and the foldback devices are located within the recess on the exposed part of the electrical lines.
10. A component as claimed in claim 9, wherein the insert includes a transversely oriented conductive path which is connected to the ground element, the foldback devices being connected to the conductive path by wire bonds.
11. A connector as claimed in any one of claims 8 to 10, wherein each foldback device is bonded directly to its corresponding line and/or to the electrically conductive path.
12. A component as claimed in any one of claims 1 to 11, which contains no capacitor between any protected line and the ground line.
13. A component as claimed in any one of claims 1 to 12, wherein the foldback devices are encapsulated by a layer of insulating material.
14. A component as claimed in any one of claims 1 to 13, wherein the foldback devices are in thermal contact with the associated electrical lines.
15. A component as claimed in any one of claims 1 to 14, which is an electrical connector.
PCT/GB1990/000824 1989-05-26 1990-05-25 Electrical device with transient protection WO1990014707A1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
GB898912144A GB8912144D0 (en) 1989-05-26 1989-05-26 Electrical device with transient protection
GB8912144.6 1989-05-26
GB909002174A GB9002174D0 (en) 1990-01-31 1990-01-31 Electrical device with transient protection
GB9002174.2 1990-01-31

Publications (1)

Publication Number Publication Date
WO1990014707A1 true WO1990014707A1 (en) 1990-11-29

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Family Applications (1)

Application Number Title Priority Date Filing Date
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Country Status (1)

Country Link
WO (1) WO1990014707A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0522974A1 (en) * 1991-07-10 1993-01-13 RADIALL Société anonyme dite: Interference protected multicontact connector

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1316226A (en) * 1961-03-10 1963-01-25 Comp Generale Electricite Semiconductor device with self-protection against overvoltage
EP0196891A1 (en) * 1985-03-29 1986-10-08 Raychem Limited Circuit protection device
FR2620271A1 (en) * 1987-09-08 1989-03-10 Thomson Semiconducteurs Semiconductor device for protection against overvoltages

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1316226A (en) * 1961-03-10 1963-01-25 Comp Generale Electricite Semiconductor device with self-protection against overvoltage
EP0196891A1 (en) * 1985-03-29 1986-10-08 Raychem Limited Circuit protection device
FR2620271A1 (en) * 1987-09-08 1989-03-10 Thomson Semiconducteurs Semiconductor device for protection against overvoltages

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0522974A1 (en) * 1991-07-10 1993-01-13 RADIALL Société anonyme dite: Interference protected multicontact connector
FR2679073A1 (en) * 1991-07-10 1993-01-15 Radiall Sa MULTICONTACT CONNECTOR PROTECTS AGAINST INTERFERENCE.
US5244416A (en) * 1991-07-10 1993-09-14 Radiall Multicontact connector protected against interference

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