RU2235389C1 - Electronic module protective device - Google Patents

Abstract

FIELD: electronic-device packages protected against unauthorized access.

SUBSTANCE: protective device built in the form of module package is designed to protect its internal components against unauthorized access without changing logic state of these components by breaking external structural components of module, including its leads, by means of any possible hardware or techniques. It has at least one anisotropic conductive shell enclosing on all sides the module interior accommodating printed-circuit or film board with circuit internal components and functional interconnections, as well as with protective circuit or separate protective circuit connected inside to shell and designed to respond to changes in electrical parameters of mentioned shell due to its breakage. Novelty is that shell is essentially at least double-layer winding with rigidly fixed turns that encloses leads and is wound on at least two parallel intertwined or interwoven insulated wires arbitrarily connected at start and finish of winding to two contact groups of protective circuit designed to function in two modes, one being mode of invocation of circuit that once identifies and stores table of paired interconnections of contacts of both groups using winding wires, and other mode of circuit functioning at desired intervals to determine current state of these interconnections and to save constant the logical state of circuit internal components only upon receiving result coinciding with that obtained in invocation mode.

EFFECT: enhanced approach to theoretical limit of protection level on external packaging end of module.

10 cl, 10 dwg

Description

The invention relates to autonomous alarm systems about breaking into barrier structures that limit the protected object, the alarm signal of which is a command to perform a protective action. The protected object is an electronic module, or rather, in-circuit elements of this module that are in a certain logical state, and the protective action is to change in advance their predetermined manner until the logical state was hacked so that it remains unknown to the intruder.

Along with this functional accessory, this device can also be attributed to the housings of electronic devices, since the barrier structures included in it are simultaneously the walls of the module housing and, in principle, provide the same protective functions with respect to its in-circuit elements as conventional housings, namely, protection against mechanical and climatic influences not related to the deliberate actions of the violator. The unity of both functions is that the housing module has the best protective properties, i.e. more tight and thick-walled, at the same time creates additional obstacles to the deliberate actions of the offender, and vice versa.

Since the analysis of the prior art did not reveal similar devices that match the subject of the invention in terms of the type of protected object and the nature of the protective action, the following is information about its more distant functional counterparts designed to protect the boundaries of territories and premises.

Known devices for burglar alarms containing at least one anisotropic conductive shell bounding the protected object from all sides. A protection circuit is connected to the shell, which responds to changes in the electrical parameters of the shell in case of violation, as a result of breaking, of the integrity of the latter. Such, for example, is an alarm device according to [1].

In this device, an anisotropic conductive shell is formed by laying along the perimeter of the protected object a signal wire that changes its conductivity from a certain initial value to zero when the intruder breaks, as a result of which the protection circuit generates an alarm. Anisotropy of the electrical conductivity of the sheath, which in this case is only available along the length of the wire, is a necessary condition for the sensitivity of the device to damage of relatively small sizes, since the current in the isotropically conductive shell can also bypass damage, as a result of which there is a clear criterion for generating an alarm signal, which can be used in the protection scheme, will be absent. Therefore, this feature was the basis of the described invention.

On the other hand, it is clear that even very dense (in the form of a multilayer winding) laying of a single signal wire along the boundaries of the protected object does not provide a sufficient level of security, since it is enough for the intruder to pre-shorten one or more wires bypassing the place of future hacking of such a sheath, so that the circuit protection did not work. In addition, even a tightly laid winding, if you do not take special measures, is technically possible to unwind, thereby ensuring unimpeded access to the volume limited by it.

Security devices with another type of anisotropy of the electrical conductivity of the shell are also known, namely, when it is a surface capacitor distributed along the entire barrier zone. Due to the fact that for a protected object of miniature size, much smaller than its distance to the ground or the nearest grounded surface, this capacitor cannot be made otherwise than two-sided, such a structure can also be considered an anisotropic conductive shell - with the presence of conductivity along each of the plates and its absence in the transverse direction, through the dielectric of the capacitor. For protected objects of relatively large sizes, the surface of the earth is used as the outer lining of the capacitor [2]. The operation of such devices (usually called capacitive electronic relays) is based on a change in the capacitance of the guard capacitor due to the approach or intrusion of the intruder. A fundamental disadvantage of such devices is the low sensitivity to damage to the plates or other violations of the initial structure of a relatively small (commensurate with the thickness of the dielectric) size, taking into account the natural temperature and time fluctuations of the capacitance of the guard capacitor.

The problem to which this invention is directed is to create a device that is absent from the available data but is very relevant for solving a certain range of problems from the field of computerization, the high efficiency of the protective functions of which is predetermined by the organization principles that are based on it and because of the fundamental simplicity and possibility of theoretical analysis of the latter is strictly provable, and can also be subjected to inextricably at any time (both at the input control stage and during operation) a challenging test. This problem is solved on the basis of the absence of real restrictions on the degree of technical equipment of the intruder, against the actions of which this device is effective, and the latter is considered to have comprehensive information about its design and similar full-scale samples. The technical result obtained by carrying out the invention consists in approaching the theoretical limit of the level of protection from the external structural design of the module, when all other security problems are associated only with the correctness of solving the accompanying software and hardware issues and the reliability of the used elemental base.

The electronic module protection device that protects against access to its in-circuit elements, without changing the logical state of the latter, by hacking using any technically possible means and techniques of the external structural elements of the module, including its conclusions, contains at least one anisotropic conductive shell, limiting on all sides the internal volume of the module, in which there is a printed or film board with in-circuit elements and functional interconnections of the module, as well as with a protection circuit, or a separate protection circuit connected internally to the shell and responding to changes in the electrical parameters of the shell in case of violation, as a result of hacking, of the integrity of the latter. This is the part of the device known from the state of the art.

According to the invention, the problem is solved in that the sheath is an envelope of leads at least a two-layer winding with rigidly fixed turns, wound in at least two insulated wires that are parallel, laid, intertwined or intertwined, connected at random at the beginning and end of the winding to two contact groups of the protection circuit, which is made dual-mode: in the activation mode, once defining and storing the table of pairwise connections with the wires of the winding ontact two groups among themselves, and in a mode of operation with a given frequency, which determines the current status of these compounds and preserves unchanged the logic state in-circuit elements of the module only when receiving the result coinciding with a specific mode of activation. The achievement of the indicated technical result is facilitated, in particular, by the fact that the execution of the protective action, namely, the change in a predetermined manner of the logical state of the in-circuit elements of the module, under this condition is ensured in any other situation, including not only a change in the current state of the connections, but also a deliberate conclusion the intruder of the external (directly connected to the winding) part of the protection circuit is out of order. This set of distinctive features is inherent in all variants of the invention without exception and will be discussed in detail in the following sections of the description. In addition, in the specific forms of its design, the following technical solutions are advisable.

The protection circuit contains a generator for cyclic polling of group contacts during the next determination of the current state of their connections in operation. Obviously, if the sequence of pulses that do not repeat from cycle to cycle, which the intruder has the ability to count, and then independently generate and run from an external generator bypassing the place of the future break-in, and each time in a new way, flows through the winding wires when determining the current state of their connections formed, best of all by random or pseudo-random algorithm, sequences, then the specified hacking technique is unacceptable.

The winding is additionally enclosed in a closed electromagnetic shield, separated from it by a dielectric layer of a randomly varying thickness, and the protection circuit contains a capacitive electronic relay that, in the activation mode, once determines and stores the value of the capacitance between the winding and the screen, and in the operation mode determines the current value with a specified frequency this capacity and keeping the logical state of the internal circuit elements of the module unchanged only when receiving a result that fits in advance set limits in relation to the value defined in the activation mode. The presence of a closed electromagnetic shield is appropriate for suppressing spurious electromagnetic radiation during a standard or specially initiated by the intruder mode of operation of the module, the analysis of which, as you know, can provide information about the logical state of its in-circuit elements. However, the main thing in this case is not such an application of a well-known technical solution for its intended purpose, but the use of an electromagnetic shield as the outer lining of the capacitor electronic capacitor relay protection capacitor, the inner lining of which is the winding itself located underneath. In order to unwind it (naturally, if the intruder understands how to overcome all other difficulties in this way), then not a local part of the winding surface, but the entire zone should be freed from the electromagnetic screen within the full extent of its turns, which will correspond to a sufficiently large change capacitance values of the guard capacitor. Thus, the aforementioned disadvantage of a capacitive electronic relay is not manifested here, but on the contrary, it provides an additional degree of protection, which, coupled with the main winding provided, is practically not cracked without the corresponding consequences of an anisotropic conductive shell around the module.

This electromagnetic shield, at least in part of its inner surface, it is advisable to provide an additional electrically conductive layer adjacent to the winding, for example, made in the form of a bandage wound with a soft uninsulated conductor, acquiring hardness and brittleness as a result of technological action, in particular a complex carbon fiber impregnated with a low viscosity in the initial state and low elastic after polymerization of the dielectric composition. Performing a part of the electromagnetic shield tightly adjacent to the winding around the last-wound (therefore, first of all, unwound) winding surface significantly increases the change in the capacitance of the guard capacitor, which must occur before the unwinding begins, thereby increasing the reliability of operation of the capacitive electronic relay in the right situation and in at the same time, practically eliminating the possibility of false alarms by setting wide limits of natural fluctuations of the ocher value hydrochloric container. The hardness and brittleness of this (essentially the most important) part of the electromagnetic screen excludes the possibility of unwinding the winding “through the screen”, which theoretically could not be overlooked if the screen was made of a sufficiently soft and flexible electrically conductive material.

The winding contains at least two sections, the turns of which are located in different planes, with the overlapping of the edges limiting the internal volume, the beginning of the sections or the groups of sections being wound continuously, located under the winding, and the ends above the winding and randomly connected to each other, forming at least of at least four pieces of insulated wire, a single winding, both the beginning and the end of which are located inside the volume it covers. This feature is a key point in the implementation of the winding in the form of a continuous and fundamentally insurmountable (under conditions of packing density and stiffness of mutual fixation of turns) barrier structure around the volume covered by it. It is an alternative to the usual execution of the winding of at least one section, in which the beginning of the winding can similarly be located inside the volume it covers, but the end inevitably turns out to be outside. Therefore, in order to connect it to the protection circuit located inside, it is necessary to lead the entire group of its constituent wires back inside through the already completed winding, which requires breaking its continuity and is very difficult in practice. A completely different situation is obtained if at least two sections of the winding, having beginnings inside the volume partially covered by them, are sequentially wound one towards the other (for example, one before and the other after installing the module board) so that the winding composed by them with overlapping edges limits the entire internal volume, and the ends of both sections meet above the winding. Therefore, in order to form a single winding from them, and, what is very important, a winding wound in one direction, it is enough to directly connect them together. The location of the turns of sections in different planes allows you to limit the internal volume on all sides by a single winding, filling the inevitable free central space in the plane of the turns of the other with turns of one section, and vice versa.

It is advisable to pre-insulate the wires of such a winding or braid it around a thread or core with predetermined technological properties, for example, a predetermined shrinkage in length when heated and / or having sufficient flexibility and strength to perform a winding, but losing at least one of these qualities as a result of technological exposure. This embodiment of a stranded winding wire is alternative with respect to littsendrat, consisting, as you know, of a group of wires passing along the axis insulated with enamel, entwined or braided on the outside with an insulating fiber. The implementation of a barrier winding from ordinary littsendrata is, of course, the most obvious, but in many respects far from the best option. Switching to a “reversed litcendrat” that meets the above requirements provides the following benefits.

Since each of the individual insulated wires is a spiral, and the central thread or core is an element providing tensile strength, it becomes possible to make such a multicore wire very strong and withstand technologically difficult types of winding with relatively thin and tensile strengths (for example , aluminum) current-carrying veins. The latter qualities, obviously, are decisive for creating damage-sensitive minimum sizes, occupying a minimum of space and practically unrolled barrier windings. Moreover, such a wire in the process of performing the winding or its technological processing can undergo tensile and compression strains without damage, the latter if its central thread or core is made of polymer with pronounced heat-shrink properties (they are practically inherent in one way or another all polymers). It is this option that makes it possible to widely use non-circular barrier windings, which on an ordinary littsendrat or a group of individual winding wires would be loose due to the inevitable sagging of part of the turns. Naturally, the heat-shrinkable wire allows you to eliminate all leaks and sagging in the winding by its final heating with a fixed end. However, the most significant potential feature of the “reversed litzendrat” in this application is that after winding, the central thread or core can be completely eliminated as an axially durable long material, being, for example, completely molten and thereby becoming an impregnation of a winding consisting of multi-pass , and even better, interlinked microspirals, or, in extreme cases, so losing from interaction with additional impregnation of the winding, in combination with the temperature Procedure, flexibility and strength that monolithic winding will be determined only used for impregnating relatively durable polymeric material. Such a winding in itself is, in principle, not unwound without damage in the form of breaks and short circuits of individual insulated wires, which allows, in some, perhaps not the most critical specific forms of execution, to do without the second degree of protection in the form of a capacitive electronic relay.

The ends of the sections located above the winding or of the groups of sections which are continuously wound are taken out of the module and are randomly connected to each other through an external switching device. As noted above, for the formation of a barrier winding, in principle, a direct connection of these ends is sufficient, the only question left is where and how this connection should be made. Its location under the electromagnetic screen, although possible, is technologically inconvenient, since there should be a minimum gap between it and the winding, and it’s practically impossible to connect multiple running ends of relatively thin enamel wires to each other, other than on a separate board . However, even if it is possible to solve all the technological problems associated with this, the most important practical possibility of this kind of device will remain unfulfilled, namely, the possibility of carrying out at any desired time - both at the stage of acceptance tests and during routine maintenance in the operation process - absolutely reliable and exhaustively complete non-destructive tests of protective functions, which may or may not be fully obtained even during manufacture due to breaks and closures of the individual wires of the winding, either partially or totally lost during operation due to some kind of failure rate components. In normal operation, this external switching device can be a short-circuit plug, detachably mounted outside the module, but, in general, it must meet the following requirement.

The external switching device is made controlled by checking the functioning of the protection circuit by modeling a violation of the integrity of the winding by a series of possible options for changing the state of the connections of its wires with respect to the state corresponding to the activation mode. Developed by this device, together with the hardware and software environment attached to it, the verification program should include cyclically repeating algorithms for setting a certain variant of the state of the winding wire connections, activating the protection circuit, bringing in-circuit elements of the module to some conditional logical state, another variant of changing the previously set table state connections (i.e. modeling the actions of the intruder) and confirmation of the fact that the protection scheme fulfills the above protections th steps to change the preassigned manner logic state in-circuit elements of the module with respect to the previously given conditional. Based on the results of this check, the manufacturer can determine the actual condition of each of the winding wires and the quality of their connections with the protection circuit, with a printout of the corresponding table included in the device form, as well as a reasonable conclusion about the full or limited suitability for operation of this product.

Between adjacent sections or layers of the winding, terminals or groups of terminals of the module are missing, and the portions of the terminals enveloped by the winding are made non-linear, for example, containing at least one turn in the case of a tape output or a bend in the case of a wire output. It is this feature that determines the required level of security from the side of the terminals, which are also one of the external structural elements of the module, and therefore, possible by penetrating inside during burglary, for example, by drilling one or more terminals from the inside of the metal. This tampering technique is unacceptable if a sufficiently thin lead is not passed through neutral material, but is directly sandwiched between the turns of the barrier winding, which are obviously sensitive to mechanical stress, strong enough to remove the metal leads, and in addition to everything indirect. Chemical removal of metal leads is generally excluded, since any etching agent for metal together with etching products is an electrolyte, the ingress of which inside the module instantly destroys its entire circuit. Consequently, the removal of such conclusions from the inside of the metal (and their insulation, in principle, can be very thin, or even completely absent due to the insulation of the winding wires) without damaging the metal or the insulation of the winding wires is a technically insoluble task, not only at the present level of technological development, but and in the foreseeable future.

In a particular practical form of execution of a device with a two-section rectangular winding, the group of module outputs are combined into a L-shape in the case of one-sided arrangement of the terminals or a T-shape in the case of their bilateral arrangement, a flexible board or a flexible section of a flexible-rigid module board, bent with respect to to the surface of the location of in-circuit elements and functional interconnections of the module. This feature characterizes the most rational for this case version of the constructive and technological implementation of the findings, which fully complies with all the above requirements with regard to security against hacking.

The invention is illustrated by drawings, including ten figures on four sheets. Separate positions in the figures (in particular, the flexible printed circuit board 34 in all its transverse sections) are depicted in a scale enlarged relative to other elements for the purpose of more illustrative illustration. Leader lines of numbered positions end with dots if the position corresponds to a structurally and technologically separate part, and arrows if the position indicates a specific place in the part.

1, 2 is a simplified structural diagram explaining the general principles for constructing an electronic module protection device using an example with a round four-section winding made in place: in an axial longitudinal section — in FIG. 1 and in a section with a scan according to FIG. 1 of its generatrix secant cylindrical surface - figure 2.

Figure 3-5 shows an example of a specific structural implementation of the implementation of figures 1, 2: a view from the side of the terminals with a partial transverse section through the external structural elements in Fig.3, an axial longitudinal section in Fig.4 and a stepwise transverse section along internal structural elements passing along the secant planes indicated in FIG. 4 — in FIG. 3.

Figures 6-8 show an example of an alternative form of construction of the electronic module protection device - with a two-section rectangular-shaped winding in place, in one of the possible embodiments - with a one-sided arrangement of terminals and an L-shaped flexible printed circuit board and designed as installed in cartridge connector: view from the side of the terminals with a partial transverse section through the internal structural elements - Fig.6, axial longitudinal section along a plane perpendicular to the plane of the board module - in Fig.7 and a longitudinal section along the secant plane indicated in Fig.7, parallel to the plane of the module board and with a partial section showing part of the internal structural elements - in Fig.8.

Figures 9, 10 show another example of a number of possible embodiments of an electronic module protection device similar to Figures 6-8 of a structural design - with a two-sided pin arrangement and a T-shaped flexible printed circuit board, made in advance by a winding made up of two rectangular frameless coils, and the socket in the form of a flat, surface mounted on a printed circuit board next structural level perspective view of a general form with a cut in _^1/4 parts - 9 and a longitudinal section of a Designated in Fig.9 secant plane - in Fig.10.

The shielded electronic module (Fig. 1) in the first form of construction is mounted on a disk printed or film board 1 with a double-sided arrangement of in-circuit elements and functional interconnects, on which is also a protection circuit. The latter has contact groups 2 and 3 (in the examples of FIGS. 1-8 — into eight contacts) connected from the inside to an anisotropic conductive shell, which limits the internal volume of the module from all sides. This sheath is a multilayer winding with rigidly fixed turns, wound in some way decorated with a group of eight insulated wires and consisting of four sections - 4, 5, 6 and 7. Connected to the contact group 2 sections 4 and 5 represent the first a group in which section 4 has non-circular coils lying in a plane perpendicular to the drawing plane — the axis of rotation during winding O ₁ , and directly continuing with round sections 5 of round shape lying in a plane, perpendicular dicular as the plane of the drawing, and the plane of the arrangement of turns of section 4 - the axis of rotation during winding O (the general axis of axial symmetry of the entire device). Section 5 is located so that it overlaps the edges of the central hole in section 4, and the turns of different sections in the overlap zone are directly in contact with each other and are as rigidly fixed from mutual movement as the turns within each of the sections separately. Therefore, penetration into the internal volume of the module through the contact zone of the continuously wound sections 4 and 5, as well as 6 and 7, is no less problematic for the intruder than through the turns of each of the sections separately. The rows of the windings of each of the sections 4-7 in figure 1 are indicated by bold vertical lines, and the electrical connections (transitions of the group of wires between the rows) in sections 5 and 7, allowing to show the complete electrical circuit of the winding, are conditionally concentrated on the right side of the figure.

The first sections of each inseparably wound group (4 and 6) are pre-wound on the frames in the form of flat rectangular plates (not shown conditionally in Fig. 1), and the second (round) sections 5 and 7 are wound in place in the existing annular gaps between the outer parts electromagnetic shield 8 (not conditionally allocated in Fig. 1) and internal caps 9 and 10 with holes in the center for turns of sections 4 and 6. The caps 9 and 10 joined together form a closed internal volume in which the module disk board is placed and where the module board is fixed 1. External functions cial module terminals 11 soldered to the circuit board 1 (in the form of separate lengths of insulated wires), are passed through grooves in place abutting the inner cap 9 and 10.

In the manufacture of the module, in the first place, a group of sections 4 and 5 was made, and section 5, upon completion of winding in the annular gap between the base of the electromagnetic shield 8 and the end face of the cap 9, was continued on the side cylindrical surface of this cap so that its upper one (in FIG. 1 ) the edge turned out to be higher than the level of the arrangement of the board 1. The end of the winding of section 5 was made near the base of the screen 8, and the end of the group of winding wires was passed into a special hole in the screen. As a result of rigid fixation (in particular, by impregnation with a low-viscosity in the initial state and low-elastic after curing by the polymer composition), the turns of sections 4 and 5 together with the structural elements containing them, the cap 9 turned out to be connected into a single structural whole by a hard winding with the base of the screen 8. Then into Board 1 was placed in the internal cavity of cap 9, and this made it possible to attach to its contact group 2 the beginning of the wire group from section 4. Conclusions 11 were laid with the corresponding bends (Fig. 2) on the side the surface of section 5 and brought out through special holes or grooves in the base of the screen 8.

Next to the contact group 3 was connected coming from the pre-wound section 6 (structurally similar to section 4, but with the axis of rotation when winding O ₂ ) the beginning of the group of wires of the second non-tear-off group of sections 6 and 7, the first of which was placed in the central the hole of the second cap 10, which closes the internal volume, after which a group of wires extending from the end of section 6 wound the outer round section 7, which ends the barrier winding (the axis of rotation during winding is O). The upper part of the electromagnetic shield 8 and cap 9 served as the accommodating parts of this section; moreover, upon completion of its winding in the corresponding annular gap, it was continued on the cylindrical surface of the terminals 11 on top of the latter and, after laying several rows, it was withdrawn by the end of its group of wires through a special groove in the lower part screen 8. Then, over the section 7 was wound made in the form of a conductive bandage the inner part of the electromagnetic screen 12, in particular a thread of complex carbon fiber, the screen is closed into a continuous shell of the annular part not highlighted in Fig. 1, and all the gaps remaining between the device parts and turns 6, 7 were filled with the same polymer material that was used for rigid fixation of the turns 4, 5. this material into the internal volume of the module between the caps 9 and 10, where the board 1 is located, is excluded by the fact that when the windings are impregnated with a low-viscosity dielectric composition, it penetrates into the capillary gaps between the wires under the action of surface tension forces s winding and winding enclosing parts, hold them, while communicating with the cavity of their relatively large size remain unfilled.

The ends of sections 5 and 7 brought out of the module are interconnected via an external switching device 13, as an example of which a passive microcircuit is shown - a “set of jumpers” installed in a contact device with the required number of terminals. In appropriate cases, the connector of the program-controlled switch is connected to the place of this microcircuit.

The above general principles of construction and technological implementation (to the extent necessary to confirm the feasibility of the invention) of barrier windings are invariant with respect to all forms of a particular design of the electronic module protection device, therefore, only changes and clarifications regarding individual details will be described in the further description.

In particular, in practice (Figs. 3–5), it is advisable to place the disk board 1 in a special carrier 14 in the form of an annular metal frame with grooves 15 made at the end for the passage of the wires of the functional terminals 11 and fix it in the carrier using a split ring made from the inside of the spring wire 16. At the edge of the board there is a short radial groove 17 for output outward for the convenience of mounting to the corresponding contact group the protection circuit of the beginning of the winding of section 4. In caps 9 and 10, stamped from a thin metal sheet, it is appropriate to extrude inwardly facing jacke 18 intended to define the correct angular position are located inside these flat shaped caps 19 carcasses sections 4 and 6 of the barrier winding.

Functionally, the electromagnetic screen in practice, from structural and technological considerations, it is advisable to make from separate parts in the form of a base 20, a cover 21 and a ring 22, and the mounting screws that are exiting outward in the form of pins are pre-installed in the stepped threaded holes of the base 20 23, used for reliable fastening of a very massive device (taking into account the fact that in order to increase the level of protection the details of the electromagnetic screen should be made of temper steel or similar strength material) on a separate metal chassis or a sufficiently thick printed circuit board of the next design level. In the central holes of the base 20 and the cover 21 there are stepped cylindrical liners 24 made, for example, of high-strength corundum ceramics, which serve as supports for the initial turns of the windings of the round sections 5 and 7. It is advisable to shape the end surfaces of the base 20 and the cover 21 in the form of cones with angles sufficiently large (to reduce the axial size of the device) at the vertices, which reduce, compared with flat ends, tensile loads on the wire when winding sections with a high ratio outer and inner diameters. For the same reasons, it is advisable to apply the torque when winding these sections from the side of the cones, for which blind technological grooves 25 for the winding machine leads are made on the outwardly flat surfaces of the base 20 and the cover 21.

The outgoing terminations of the functional terminals 11 are passed through the radial grooves 26 in the base 20 while putting on the segments of the insulating tubes, and the end of the winding of section 5 through a special hole 27. The end of the winding of section 7 is passed through the shorter through radial groove 28 base 20.

The ring 22 of the electromagnetic shield, after winding the conductive bandage 12 over the section 7, is worn from the side of the cover 21 and fixed in relation to other parts by installation in a special internal groove of the split spring ring 29 (the section of the ring should be located at the output level of the ends of the winding). The reliability of the electrical contact between the individual parts of the screen is ensured by applying it externally to the joint zone of the electrically conductive compound 30.

Cementing all sections of the winding together with the bandage and connecting them to the containing parts, the insulating compound 31 (low viscosity dielectric composition without solvent, for example, on an oligoester acrylate base) is poured into the internal volume through the through radial grooves in the base 20, and its excess over the split ring 29 is specially left in the cavity that combines all the grooves of the cavity through which the fill is made, to obtain a non-separable structure, moisture protection and reliable fixation of all functional and winding leads in.

In this design example, there is no special design for the ends of the winding leads prepared for installation, released outward from the hole 27 and groove 28. It is assumed that, upon completion of the device manufacture, they are unsoldered with an excess of length onto the satellite technological printed circuit board, on which - passing tests, packaging and delivery to the customer. After removing the device from the satellite and installing it with fixing screws 23 at a constant place, these conclusions are soldered without excess length to the board of the next structural level, on which an external switching device is installed. This ensures the inextricable linking of the protection device of the electronic module to the place of its installation during operation, which, in principle, can be considered as an additional (external to the module) degree of protection.

The described embodiment of the device with a round four-section winding, made locally, is characterized by the fact that, with a relatively large number of parts and technological transitions during manufacturing, it is quite simple and with low costs for the preparation of production is realized for small volumes of output, while ensuring convincing achievement of the specified technical result. Its advantages are high mechanical strength and maximum level of security. However, it is not without serious flaws: firstly, it has poor serial suitability and, secondly, it is impossible to obtain good weight and size indicators, since, on the one hand, four sections of the winding must be placed in axial size, overlapping, and, with on the other hand, a round (disk) module board does not provide efficient use of space.

An alternative form of design of the device, namely, with a two-section rectangular winding, is free from these shortcomings. This form can be implemented in two versions: as in the previous case, with an in-place barrier winding (guaranteed high level of security due to the absence of gaps between the winding sections sequentially wound one on top of the other around the module board), as well as with a winding composed of two prefabricated and nested one into another sections. The latter is optimal for the conditions of large-scale production, since it makes it possible to obtain sections as components in cooperation with a specialized enterprise. Theoretically, in the second embodiment, a certain gap should be provided between the winding sections, which casts doubt on the completeness of achieving the specified technical result. However, if we take into account not abstract hypothetical, but actually predictable technical means and techniques that can be used to implement hacking, then the special structural and technological aspects described below, which underlie this option, being taken into account in its analysis, provide sufficient grounds for a positive conclusion about the possibility of its use in the most widespread areas of application.

Regardless of the accepted option, this form of design of the electronic module protection device provides the widest choice of both its external design and the associated method of installing the next design level on the board, as well as the option of connecting to the external switching device necessary for testing the protective functions, including the sub-option, when it, as such, is explicitly absent. Therefore, in the two examples below, polar designs are presented in many respects, taking into account the fact that the possibility of combining the new technical solutions embedded in them, both among themselves and with the known ones, allows us to get a complete picture of the potential technical capabilities of this form of constructive execution of the subject of the invention.

The board of the electronic module 1 of a rectangular configuration in the first example (Fig.6-8) is placed inside a flat sleeve 32, around which the inner section 5 of the barrier winding is pre-wound and impregnated. The gaps between the walls of the sleeve 32 and the mounting surfaces of the board 1, determined by the maximum height of the in-circuit elements of the module located on each of its sides, are set, for example, by racks 33 mounted on the board and tightly adjacent to the walls of the sleeve. The contact pads of the module functional conclusions are concentrated along one of the edges of the board 1 located at the hole of the sleeve 32. An internal parallel row of conductors of a flexible L-shaped printed circuit board 34, made, for example, of foil-coated polyimide, is soldered to them. Contact groups 2 and 3 of the protection circuit are arranged in a row along the opposite edge of the board 1.

Outside, to the section 5, in the transverse direction with respect to the winding and on its narrow sides, multifunctional blocks 35 and 36 are attached, the connecting dimensions of which are set slightly smaller than the sizes of section 5 in order to obtain a sufficient overlap of the sections of the barrier winding. The end of the winding of section 5 is passed through a special hole 37 in the block 36. The beginning of the winding of this section is soldered to the contact group 2 of the protection circuit. This operation was performed before bending the flexible board 34, when the edge of the board 1 with contact groups 2 and 3 was pulled out from the sleeve 32. Then, the beginning of the winding of section 7 to the contact group 3 was soldered. After returning to the place of the board 1 in the sleeve 32, the flexible board 34 was bent twice at a right angle so that the angles of rotation of its conductors were lying on the wide side of section 5, and the edge opposite the internal functional terminals fell into a special recess of the block 35. Then this state of the flexible board 34 was fixed by applying x her belt band 38 of a thin and sufficiently flexible polymer film covering its width section 5 together with the pad connecting portions 35 and 36, thereby forming a closed on all sides by the capsule, which is enclosed within the module board 1. The beginning of the winding of the outer section 7, pre-connected to the board 1, in the process of applying the bandage 38 was allocated to the edge of the block 35. Upon completion of the above steps, the resulting structure was completely prepared for winding in place of the section 7 of the barrier winding with the axis of rotation during winding through the centers blocks 35 and 36. The end of the winding of the outer section 7 is passed through another hole or groove in the block 36. An electrically conductive bandage 12, for example, made of carbon woven tape, is the same width as the bandage tape 38 over the winding.

The block 35, which serves for the external design of the functional conclusions, in particular, can simultaneously be the base of the plug connector intended for connecting the electronic module to the next structural level of the equipment. To do this, it must have special holes in which the spring slots 39 are inserted, closed on the outside with a cover with holes 40. The flexible printed circuit board 34 is designed so that the pitch of its conductors, corresponding to the functional terminals of the module, is on the edge of the board lying in the recess of the block 35 , would be aligned with the pitch of the connector pins. In this case, the most simple and at the same time reliable direct connection of the conductors of the flexible printed circuit board to the connector contacts is obtained, for example, by soldering, as shown in the figures, or by crimping. In practice, in some cases, it is advisable to further expand the functions of the block 35: it may have a special socket for placing a backup electrochemical power source for the module (or a pair of sources, which allows them to be replaced successively without removing the voltage), the connection of which (of which) with the module is also should be through the conductors of a flexible printed circuit board 34.

The block 36, which serves for the external design of the winding terminals, can also be used as the base of the plug connector connecting them to an external switching device. In the simplest version, an auxiliary rigid double-sided printed circuit board 41 is used for this, to the conductors located on opposite sides of which the ends of sections 5 and 7 of the barrier winding removed from the block 36 are soldered. At the end of the soldering, the board 41 is inserted into the special grooves of the recess in the block 36 and fixed in it by an electrical insulating compound, in the volume of which both the ends of the winding and the soldered joints are. The connector contacts are the parts of the printed conductors of the board 41 extending beyond the block 36. The contacts 42 of the external switching device are spring brackets embedded in the connecting block 43 and secured against falling out by the cover 44. Such a switching device, being installed on the edge of the board 41, provides durable and reliable connections located one on the other on opposite sides of the printed circuit board 41, to which the ends of the windings of sections 5 and 7 are connected. From accidental removal of this ring A self-adhesive tape 45 protects the dice at the same time lying along the entire perimeter of the protruding edge of the block 36 and the corresponding edge size of the block 43. Testing of protective functions is carried out through a technological block, similar in size to the block 43, but with a doubled number of contacts, from each of which are located on one the level of the other printed conductors of the board 41 individually.

The electromagnetic screen 8 is made in the form of a stamped (elongated) metal cup of rectangular shape, inside which a previously manufactured product is inserted tightly (to ensure electrical contact with the conductive bandage 12). The edges of the glass are decorated with corners, in the openings of which flanges 46 for captive screws are flanged, intended for fastening to the connector block of the next structural level of the equipment. At the bottom of the glass there is a rectangular hole designed to exit the outer part of the shoe 36. Technological ribs 47 are extended in the walls of the glass, the internal cavities of which serve to feed the compound 31, poured through the edges of the glass, to the parts of the winding of the outer section 7 located closer to the bottom (inner section 5 was soaked in advance). Further distribution of the compound 31 during the impregnation process is carried out due to the wick action of the conductive bandage 12, which is facilitated by its implementation of complex carbon fiber, as well as by capillary gaps between the winding wires. An excess of compound 31, or a specially prepared and additionally filled compound with mineral filler, is left at the edges of the glass to reliably mechanically fix the block 35 with the cover 40, to which considerable effort is applied when installing and removing the product in the apparatus. Such a design of the electronic module protection device can be characterized as a structurally self-contained cartridge suitable both for permanent installation inside the equipment and for separate storage with periodic connection via an external port intended for it.

Another embodiment of the electronic module protection device with a two-section rectangular winding (Figs. 9, 10) is characterized in that both sections of the barrier winding, both internal 5 and external 7, were wound, for example, into four wires and impregnated in advance in the form two frameless rectangular coils in terms of These coils can also be wound with wires with an additional adhesive layer deposited on top of the main insulation, or with the “reverse littsendrat” discussed above, the central thread of which is made of heat-shrinkable low-melting polymer. In the latter cases, instead of impregnating the windings, heat treatment is used on special mandrels.

The dimensions of the inner window of the outer section 7 are selected to exceed the outer dimensions of the inner section 5 by an amount sufficient for the free introduction of section 5, together with the module 1 board pre-placed there and bent in two planes by a flexible printed circuit board 34, inside section 7. Start of the winding section 5 was connected to the contact group 2 of the protection circuit in advance, and the beginning of the winding of section 7 was connected (with the necessary margin of length) to the contact group 3 of the protection circuit when the position of section 5 was partially entered (on the right in FIG. 10), in which the contact group 2 was already under the winding of section 7, and the contact group 3 was still located outside (for clarity, figure 10 polymer compounds are not shown). To simplify the installation operations, the contacts of groups 2 and 3 are brought to the end of the corresponding edge of the module 1 board. After the introduction of section 5 to the central place in section 7, the margin of the length of the beginning of the winding of section 7 was tucked under section 5 into a gap free of flexible printed circuit board 34, as shown in FIG. 10 by a dashed line. Then, on both sides of the inner window of section 7, U-shaped metal brackets 48 were tightly inserted, with the exception of corners and cross-sections, fixing the central position inside of section 5.

In this design example, the flexible printed circuit board 34 is shown T-shaped, which, obviously, allows you to arrange the functional conclusions of the module on its two sides. However, it is of interest to demonstrate another functionality, namely, the implementation of an external switching device, in which it, as such, is absent, but all its inherent functions are performed. To this end, on the outward-facing edge of the flexible printed circuit board 34, opposite the functional terminals, loop-shaped (pairwise interconnected) winding terminals 49 are made that are not connected to the rest of the circuit and are passed inside the module from the side of section 7 to which the ends of the windings of both sections are suitable. They are soldered, after installing the brackets 48, to the internal contact pads of the loop-shaped conductors of the winding terminals 49. This ensures, on the one hand, the connection of sections 5 and 7 into a single barrier winding, and, on the other hand, external access to this connection for necessary tests through an external switching device, which, in this case, is the set of loop-shaped terminals 49. In the form shown in Fig. 10 (in the delivery state) it allows partial (for short circuits) testing of protective functions minutes, using simultaneous touches conductive subject of two or more of loop conductors. For complete testing, which involves enumerating all possible options for both short circuits and breaks in the conductors of the sections of the barrier winding, the conclusions 49 should be shortened to the width of the jumpers connecting them in pairs and connected through a printed circuit board of the next design level. In the absence of the need for complete testing of soldering somewhere in the equipment, conclusions 49 are not required. In this case, in order to avoid tripping of the protection circuit against accidental contact with terminals 49, they must be insulated.

The presence of a gap not filled with a barrier winding inside section 7, communicating with the volume inside section 5, where the board 1 of the electronic module is located, involves the adoption of special design and technological measures to increase its level of protection. The first of these measures is a significant increase in the length of section 7 compared with the width of section 5, which drastically restricts access when entering this gap, limiting it to only two edges of the board 1, on one of which are functional terminals, so that go out, and on the other - contact groups of the protection circuit, the signals on which are not related to the functional affiliation of the module. Intracircuit elements, the logical state of which is of interest to the intruder, should be located in the central area of the board 1. A certain increase in the dimensions of the device in terms of a serious drawback is not, since the critical size in most cases is the height. The second measure is to increase the protection efficiency in this critical place from the side of the capacitive electronic relay, which is achieved by ensuring reliable electrical contact between the brackets 48 and the inner part of the electromagnetic shield 12. Then a flexible conductive probe, which can be introduced by the intruder near these brackets in the immediate vicinity of the winding , will sharply increase its capacity on the screen, which will trigger the protection circuit. And finally, the main measure is filling (for example, putty with a spatula) of both open ends of section 7, over the brackets 48, with a special thixotropic thermosetting dielectric composition 50 containing relatively coarse (with an average size exceeding the width of the protected gap) grains as a filler high-strength abrasive material, for example, corundum, carbide or boron nitride, etc. (see Fig. 9, in Fig. 10 it is not shown to show other structural elements). Composition 50, in contact simultaneously with the winding of section 7 and the strips 48, as well as penetrating, when applying through the corners of the latter, into the gap between sections 5 and 7, which is protected against penetration by breaking, due to the presence of large grains with sharp edges from high-strength abrasive material in its polymer binder, the removal of which from there without damage to the wires of the windings is impossible, increases to the necessary degree the level of security of the device. This measure simultaneously allows to completely exclude the possibility of uncontrolled ingress of the module during the final pouring of the low-viscosity compound 31, which can damage the installation of in-circuit elements of the module due to mechanical stresses during polymerization, due to the fact that the composition 50, covering on both sides the cavity inside section 7, turns the latter into a liquid-tight capsule, the filling of which with compound 31 can be carried out in any position relative to the vertical and with the joint curing of the material s 31 and 50 in one stage of heat treatment (due to the thixotropy of the composition 50).

Being an element designed for surface mounting on a printed circuit board of the next design level, the described device contains, like the one shown in FIGS. 3-5, a composite electromagnetic screen consisting of stamped bases 20 and a cover 21 in the form of a cap, and the side of the screen is represented by the sides of the latter . The inner part 12 of the electromagnetic screen is a piece of carbon fabric tape that wrapped the product before tight fitting in the cap 21. Reliable contact of the screen with the strips 48 is ensured by the fact that the edges of these strips are protruded and pressed into the carbon fabric 12 during installation pressed thereby by its other side to the cap 21. The low-viscosity impregnating compound 31 is poured into the free volume of the inner cavity of the cap, after which the cap was closed on top of the base 20. Isolation from the tap of the functional and winding terminals, which are direct extensions of the printed conductors of the flexible circuit board 34, is provided with strips of electrical insulation tape 51 previously applied to the cap 21. to the side of the base after finishing. The entire device is fastened to a circuit board of the next design level by petals 53 protruding from the base, at the edges of which there are grooves for fixing screws.

The protection device of the electronic module operates as follows.

Since the connection of the wires of the sections 4, 6 of the barrier winding to the contact groups 2, 3 of the protection circuit was carried out in an arbitrary order, and, in addition, the ends of the sections 5, 7 were randomly connected to each other through an external switching device 13, contact groups 2, 3 as a result, they turned out to be pairwise interconnected by one of N! almost equally likely options, where N is the number of wires of the winding and, accordingly, contacts in groups. In particular, for four wires and contacts of each group, the number of pairwise connection options is 24, and for eight - 40.320 (without taking into account the possibility of breaks and short circuits between several winding wires during the manufacturing process of the device, which with a sufficient total number can be allowed, with transferring the device to the “conditionally suitable” category). Actually realized option, the characteristic of which is a table of pairwise connections by wires of the winding of contacts of both groups between each other, is determined and stored by the protection circuit in the activation mode.

Damage to the barrier winding during burglary or an attempt by the intruder to connect the winding to the winding bypassing the penetration site due to the tight mutual fixation of the winding wires, tight laying and a sufficiently small diameter, as well as a sufficient number of layers, is inevitably accompanied by ruptures and / or short circuits of one or more wires As a result, the connection table defined in the activation mode is changed in at least one binary digit. Therefore, the next determination by the external (connected to the winding) part of the protection circuit of the current state of these connections in the operating mode will give a result different from that determined in the activation mode, as a result of which the internal (connected to in-circuit elements) part of the protection circuit will not receive a command to cancel the protective action, which otherwise, it is done automatically. The same thing will happen if the intruder breaks down the external part of the protection circuit, accessible to him through the winding leads, for example, with a voltage pulse (it is natural that the external and internal parts of the protection circuit should be isolated to the maximum extent). This is the principle of operation of the main degree of protection provided by the device - protection, first of all, from microdamage. This degree of protection is inherent in all forms of constructive execution of the subject invention.

On the other hand, it is possible that the intruder will choose a different trick, namely, he will try, acting in a larger volume of space than in the previous case, without damaging the wires and taking advantage of the insufficient mechanical strength of the material connecting them, to unwind at least one turn the outer section 7 of the barrier winding. But for this, he will need in one way or another to remove a sufficiently large surface of the layer 12 of the electromagnetic screen 8 adjacent to the winding, thereby substantially changing the capacitance between the screen and the winding. Exceeding the value of this capacitance beyond predetermined limits will lead to the fact that the capacitive electronic relay, for its part, does not issue a command to the inside of the protection circuit to cancel the protective action. This is the principle of operation of the second degree of protection of the device - protection, first of all, from macro damage.

Joint and independent operation in the operation mode of both degrees of protection, the non-zero logical product of the signals of which is a command to cancel the protective action performed by the protection circuit automatically, using particular technical solutions described in the dependent patent claims aimed at increasing the efficiency of both the first and second , ensures the achievement of the specified technical result with a completeness sufficient for any of the possible fields of application.

Literature

1. USSR author's certificate N 215762, published 03.04.1968.

2. USSR author's certificate N 297978, published on 03/11/1971.

Claims (10)

1. The protection device of the electronic module, which protects against access to its in-circuit elements, without changing the logical state of the latter, by hacking using any technically possible means and techniques of the external structural elements of the module, including of its conclusions, containing at least one anisotropic conductive shell, limiting on all sides the internal volume of the module, in which there is a printed or film board with in-circuit elements and functional interconnections of the module, as well as with a protection circuit, or a separate protection circuit connected internally to the shell and responsive to changes in the electrical parameters of the shell in case of violation, as a result of breaking, the integrity of the shell, characterized in that the shell is an envelope of conclusions at least two-layer winding with rigidly fixed coils, wound in at least two insulated wires, laid in parallel, interlaced or intertwined with each other, randomly connected at the beginning and end of the winding to two contact groups of the protection circuit, which is made dual-mode: in the activation mode once defining and storing the table of pairwise connections by wires of the winding of contacts of both groups with each other, and in the operation mode with a given frequency determines the current the state of these compounds and the logical state of the internal circuit elements of the module that remains unchanged only when a result is obtained that matches the one defined in the activation mode. 2. The device according to claim 1, characterized in that the protection circuit comprises a generator for cyclic polling of group contacts during the next determination of the current state of their connections in operation. 3. The device according to claims 1 and 2, characterized in that the winding is additionally enclosed in a closed electromagnetic screen, separated from it by a dielectric layer of a randomly varying thickness, and the protection circuit contains a capacitive electronic relay that, in the activation mode, once determines and stores the value of the capacitance between winding and screen, and in the operating mode with a given frequency, it determines the current value of this capacity and keeps the logical state of the in-circuit elements of the module unchanged only at the floor value of the result, falling within predetermined limits with respect to the value determined in the activation mode. 4. The device according to claim 3, characterized in that the electromagnetic screen at least in part of its inner surface is provided with an additional electrically conductive layer adjacent to the winding, for example, made in the form of a bandage wound with a soft uninsulated conductor, acquiring hardness and brittleness as a result of technological impact in particular, a complex carbon fiber impregnated with a low viscosity in the initial state and low elastic after polymerization with a dielectric composition. 5. The device according to claims 1 to 4, characterized in that the winding contains at least two sections, the turns of which are located in different planes, with overlapping edges limiting the internal volume, and the beginning of the sections or inseparably wound groups of sections are located under the winding, and the ends above the winding and in random order are interconnected, forming a single winding composed of at least four segments of an insulated wire, both the beginning and the end of which are located inside the volume covered by it. 6. The device according to claim 5, characterized in that the insulated wire of the winding is pre-twisted or braided around a thread or core with predetermined technological properties, for example, a predetermined shrinkage in length when heated and / or having sufficient flexibility and strength to perform the winding, but losing at least one of these qualities as a result of technological impact. 7. The device according to PP.5 and 6, characterized in that the ends of the sections located above the winding or the groups of sections continuously wound are removed from the module and are randomly connected to each other through an external switching device. 8. The device according to claim 7, characterized in that the external switching device is controllable, verifying the functioning of the protection circuit by modeling a violation of the integrity of the winding by a series of possible variations in the state of the connections of its wires with respect to the state corresponding to the activation mode. 9. The device according to claims 1 to 8, characterized in that between adjacent sections or layers of the winding leads are missing leads or groups of leads of the module, and the portions of the leads enveloped by the winding are made non-linear, for example, containing at least one turn in the case of a tape output or bending in case of wire output. 10. The device according to claim 9, characterized in that the group of module leads are combined in a L-shaped case in case of one-sided arrangement of the terminals or T-shaped in the case of their two-sided arrangement, a flexible board or a flexible portion of a flexible-rigid module board, curved with respect to the surface location of in-circuit elements and functional interconnections of the module.

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