CN211827459U - Capacitive coupling type detection anti-dismounting device and POS machine - Google Patents
Capacitive coupling type detection anti-dismounting device and POS machine Download PDFInfo
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- CN211827459U CN211827459U CN202020403952.9U CN202020403952U CN211827459U CN 211827459 U CN211827459 U CN 211827459U CN 202020403952 U CN202020403952 U CN 202020403952U CN 211827459 U CN211827459 U CN 211827459U
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Abstract
The utility model provides a capacitive coupling formula detects prevents tearing open device and POS machine increases coupling capacitance formula and prevents tearing open the structure on the basis of structure is prevented tearing open in the tradition, and coupling capacitance does not directly use the Tamper signal for coupling capacitance coupling to the detection signal of telecommunication that Tamper signal obtained can not directly expose in preventing tearing open switch department, promotes the detection signal of telecommunication and prevents the security that detects and the degree of difficulty that is attacked. The detection circuit detects the capacitance value voltage of the coupling capacitor to output a detection electric signal, so that the detection accuracy is improved, the implementation method and the circuit are simple and reliable, and meanwhile, other control circuits can be continuously expanded at the later stage of the detection circuit.
Description
Technical Field
The application belongs to the field of electronic circuits, and particularly relates to a capacitive coupling type detection anti-dismounting device and a POS machine.
Background
Tamper signal line: a signal line whose level change is detectable by a detection circuit which triggers a security mechanism, erasure of keys and other sensitive information when the detection circuit detects that the level on the signal line does not correspond to a set level value. The anti-disassembly switch: once the Tamper switch is separated, the detection circuit triggers the security mechanism to erase keys and other sensitive information;
at present, the existing anti-dismantling switch controls the on-off of a pointer signal through the pressing of carbon particles or snap pieces, so that the function of the anti-dismantling switch is realized, the pointer signal is directly arranged on the switch, so that the anti-dismantling switch is easy to detect and break and lose efficacy, only two effective contacts are arranged, and the anti-dismantling switch is easy to attack and lose efficacy, so that the anti-dismantling switch is relatively weak in anti-attacking capacity.
SUMMERY OF THE UTILITY MODEL
An object of the application is to provide a capacitive coupling formula detects prevents dismouting and POS machine, aims at solving two effective contacts of traditional anti-disassembly switch and prevents dismouting switch, prevents the problem that attack ability is more weak.
The first aspect of the embodiment of the present application provides a capacitive coupling type detection anti-dismounting device, locate on the circuit substrate, include:
the anti-disassembly structure comprises a first signal contact and a conductive connecting sheet, wherein the first signal contact is arranged on a first conductive layer of the circuit substrate and used for accessing a Tamper signal, and the conductive connecting sheet covers the first signal contact and welds or directly presses the first signal contact;
the coupling conducting strips are arranged on the second conducting layer of the circuit substrate, and each coupling conducting strip is arranged opposite to one anti-dismounting structure to form a coupling capacitor; and
and the detection circuit is connected with the coupling conducting strip and is used for outputting a detection electric signal according to the capacitance change of the coupling capacitor.
In one embodiment, each of the tamper-evident structures further includes at least one second signal contact electrically isolated from the first signal contact on the first conductive layer, and the conductive connecting piece covers and is soldered or directly pressed on the first signal contact and the second signal contact.
In one embodiment, the detection circuit comprises:
the input end of the access circuit is connected with the coupling conducting strip, and the drive voltage is output based on the voltage of the coupling capacitor;
and the control end of the switch tube is connected with the output end of the access circuit, and the switch tube is switched on and off under the driving of the driving voltage so as to output the detection electric signal at the first conduction end or the second conduction end of the switch tube.
In one embodiment, the access circuit comprises a diode and a capacitor, wherein the anode of the diode is used as the input end of the access circuit, the cathode of the diode is connected with one end of the capacitor and is used as the output end of the access circuit, and the other end of the capacitor is grounded.
In one embodiment, the access circuit further comprises a pull-up resistor or a pull-down resistor, and the pull-up resistor or the pull-down resistor is connected to the cathode of the diode.
In one embodiment, the switch tube is an NPN transistor or an NMOS tube.
In one embodiment, the tamper-proof structure further includes a protection signal ring disposed on the first conductive layer, the protection signal ring is electrically isolated and enclosed outside the first signal contact and the second signal contact, and the protection signal ring is electrically isolated from the conductive connecting sheet.
In one embodiment, the protection signal ring, the first signal contact and the second signal contact are gold fingers or exposed copper layers disposed on the first conductive layer.
In one embodiment, the first conductive layer is a surface layer of the circuit substrate, and the second conductive layer is an intermediate layer of the circuit substrate.
A second aspect of an embodiment of the present application provides a POS machine including the capacitive coupling detection tamper-evident device as described above.
Foretell capacitive coupling formula detects prevents tearing open device increases coupling capacitance formula and prevents tearing open the structure on the basis of structure is prevented tearing open in the tradition, and coupling capacitance does not directly use the tamp signal for coupling capacitance coupling to the tamp signal and the detection signal of telecommunication that obtains can not directly expose in preventing tearing open switch department, promote the detection signal of telecommunication and prevent the security that detects and the degree of difficulty that is attacked. According to the detection circuit, the capacitance value voltage of the coupling capacitor is detected to output the detection electric signal, the detection accuracy is improved, the implementation method and the circuit are simple and reliable, and meanwhile, other control circuits can be continuously expanded at the later stage of the detection circuit.
Drawings
Fig. 1 is a schematic structural diagram of a circuit substrate of a capacitive coupling detection tamper-evident device according to an embodiment of the present disclosure;
fig. 2 is a schematic structural diagram of a capacitive coupling detection tamper-evident device according to a first embodiment of the present disclosure;
FIG. 3 is a schematic structural diagram of a capacitive coupling detection tamper-evident device according to a second embodiment of the present application;
fig. 4 is a schematic structural diagram of a capacitive coupling detection tamper-evident device according to a third embodiment of the present application.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present application clearer, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.
It will be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, refer to an orientation or positional relationship illustrated in the drawings for convenience in describing the present application and to simplify description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present application.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.
Referring to fig. 1, the capacitive coupling type detection anti-tamper device applicable to a POS (Point of Sales) device provided in the embodiment of the present application is disposed on a circuit substrate, the circuit substrate of the embodiment is a multilayer board, and has a first conductive layer L1 located on a surface layer and a second conductive layer L2 located in an intermediate layer, and an electrical signal located in the intermediate layer is not easy to be detected, so that the safety of the anti-tamper device can be improved; in other embodiments, the circuit substrate is a plurality of single-layer boards, and the first conductive layer L1 and the second conductive layer L2 are respectively located on different single-layer boards.
Referring to fig. 1 to 3, the capacitive coupling type detecting detachment prevention apparatus includes at least one detachment prevention structure 100, at least one coupling conductive sheet and at least one detecting circuit, the detachment prevention structure 100 includes a first signal contact P1 disposed on a first conductive layer L1 of a circuit substrate and used for accessing a pointer signal, and a conductive connecting sheet (not shown), the conductive connecting sheet covers the first signal contact P1 and welds or directly presses the first signal contact P1, the detachment prevention structure 100 is a conventional detachment prevention structure 100, and the first signal contacts P1 are one or more than two electrically isolated contacts on the first conductive layer L1. The conductive connecting sheet is made of conductive materials such as metal dome sheets, carbon particles, copper-exposed FPC or copper foil.
The coupling conducting strips 200 are arranged on the second conducting layer L2 of the circuit substrate, and each coupling conducting strip 200 is arranged opposite to one anti-disassembly structure 100 to form a coupling capacitor C0; it is understood that the number of the tamper-proof structure 100 and the number of the coupling conductive pads 200 should be the same, the first signal contact P1 and the conductive connection pad of the tamper-proof structure 100 constitute one plate of the coupling capacitor C0, and the coupling conductive pad 200 constitutes the other plate of the coupling capacitor C0. The coupling conductive sheet 200 is made of copper exposed on the second conductive layer L2, or is welded to a conductive metal sheet on the second conductive layer L2.
The detecting circuit 300 is connected to the coupling conductive strips 200, and the detecting circuit 300 is used for outputting a detecting electrical signal according to the capacitance change of the coupling capacitors C0. it is understood that the detecting circuit 300 may be a single detecting circuit for simultaneously detecting the voltages of a plurality of coupling capacitors C0, or a plurality of detecting circuits corresponding to the number of the coupling capacitors C0, and each detecting circuit is connected to each coupling capacitor C0 for detecting the voltage thereof. During the detection of the coupling capacitor C0 by the detection circuit 300, a default level signal is outputted in a normal state to indicate that the tamper apparatus is normal, and when a voltage change of the coupling capacitor C0 is detected by the detection circuit 300 to change the output level state, the tamper apparatus is attacked or removed.
Therefore, the capacitive coupling type detection anti-disassembly device is additionally provided with a coupling conducting strip 200 on different conducting layers of the original anti-disassembly structure 100 to form a coupling capacitor C0, the state of the Tamper signal is confirmed by detecting the voltage change on the coupling conducting strip 200 to achieve the purpose of anti-disassembly protection, and the coupling conducting strip 200 is not directly exposed outside the circuit substrate due to the fact that the coupling conducting strip 200 is arranged in the inner layer of the circuit substrate, so that the safety of the Tamper signal is improved. Through this scheme can not only prevent tearing open coupling capacitance C0 change detection mechanism, guarantee again that the tamp signal has kept away from and has prevented tearing open the point, promoted tamp signal itself and prevented the security of surveying.
Referring to fig. 4, in one embodiment, each tamper structure 100 further includes at least one second signal contact N1, the second signal contact N1 is electrically isolated from the first signal contact P1 on the first conductive layer L1, and the conductive connecting pad covers and is soldered or directly pressed to the first signal contact P1 and the second signal contact N1. The first signal contact P1, the second signal contact N1 and the conductive connecting sheet in the anti-disassembly structure 100 form a traditional anti-disassembly switch, and for the capacitive coupling type detection anti-disassembly device, the anti-disassembly detection mechanism of the Tamper signals of the two conductive layers is provided, so that the safety is improved. In contrast to the embodiment of fig. 4, in the embodiments of fig. 2 and 3, the second signal contact N1 of the Tamper-proof structure 100 is removed (or disposed at another position), so that a plurality of Tamper-proof switches can be expanded based on a Tamper signal, as shown in fig. 3, without departing from the conventional Tamper-proof structure.
Referring to fig. 2 to 4, in one embodiment, the detection circuit 300 includes: access circuit 302 and switching tube Q1. The input end of the access circuit 302 is connected with the coupling conducting strip 200, and outputs a driving voltage V1 based on the voltage of the coupling capacitor C0; the control end of the switching tube Q1 is connected with the output end of the access circuit 302, and the switching tube Q1 is switched on and off under the driving of the driving voltage V1 so as to output a detection electrical signal at the first conducting end or the second conducting end thereof.
In one embodiment, the access circuit 302 includes a diode D1 and a capacitor C1, an anode of the diode D1 is used as an input terminal of the access circuit 302, a cathode is connected to one terminal of the capacitor C1, and as an output terminal of the access circuit 302, the other terminal of the capacitor C1 is grounded. The access circuit 302 further includes a pull-up resistor or a pull-down resistor connected to the cathode of the diode D1. The switching tube Q1 is an NPN transistor or an NMOS tube. In this embodiment, the collector of the NPN transistor or the drain of the NMOS transistor serves as the output terminal P0 of the detection circuit 300.
A signal to be detected (a pointer signal) is output to the detection circuit 300 from the first signal contact P1 (or other useful signals) through the coupling capacitor C0 by the driving voltage V1, when the conductive connecting piece is pressed, the value of the coupling capacitor C0 is large, and at this time, the value of the coupled driving voltage V1 is larger than the on-off voltage of the switching tube Q1, the switching tube Q1 is turned on, so that the detection electrical signal of the output end P0 of the detection circuit 300 is pulled low and kept in an unfired state, once the conductive connecting piece of the anti-disassembly structure 100 is loosened, the coupling capacitor C0 is reduced, the driving voltage V1 is reduced to be less than the on-off voltage of the switching tube Q1, the switching tube Q1 is turned off, so that the detection electrical signal of the output end P0 of the detection circuit 300 is increased to trigger, and whether the anti-disassembly switch is disassembled is judged.
The magnitude of the voltage driving voltage V1 can be adjusted by changing the value of the capacitor C1, the diode D1 has the functions of forward conduction and reverse cut-off, meanwhile, a pull-up resistor or a pull-down resistor can be added at the position of the driving voltage V1 to change the initial value of the driving voltage V1, the rear end of the output end P0 of the output detection circuit 300 can continue to expand other control circuits, the switch tube Q1 in the normal pressing state of the conductive connecting piece is switched on, the output detection electric signal is at a low level, the switch tube Q1 in the loosening state of the conductive connecting piece is cut off, and the output detection electric signal is at a high level.
In one embodiment, the tamper resistant structure 100 further includes a protective signal ring 105 disposed on the first conductive layer L1, the protective signal ring 105 is enclosed outside the first signal contact P1 and the second signal contact N1 in electrical isolation, and the protective signal ring 105 is electrically isolated from the conductive connecting pad. The protective signal ring 105 can provide the tamper-evident structure 100 with a tamper-evident protection at the outermost side that causes a change in an electrical parameter loaded on the protective signal ring 105 to cause a trigger when the protective signal ring 105 is electrically connected to the conductive connection pad.
In one embodiment, the protection signal ring 105, the first signal contact P1 and the second signal contact N1 are gold fingers or exposed copper layers disposed on the first conductive layer L1.
The capacitive coupling type detection anti-dismounting device is characterized in that a PCB (printed circuit board) internal detection signal which cannot be directly detected is newly added to the original traditional anti-dismounting structure, so that the safety of an anti-dismounting switch and the difficulty of being attacked are greatly enhanced. The coupling capacitor is connected with the Tamper signal instead of being directly connected, so that the Tamper signal of the coupling capacitor detection part is not directly exposed at the anti-dismounting device, and the safety of the Tamper signal is improved. The detection circuit 300 controls the conduction state of the switching tube Q1 by controlling the magnitude of the driving voltage V1 through the rectification characteristic of the diode D1 and the capacitor C1 or the pull-up resistor, so that the detection accuracy is realized, the implementation method and the circuit are simple and reliable, and in addition, other control circuits can be continuously expanded at the later stage of the detection circuit.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.
Claims (10)
1. The utility model provides a capacitive coupling formula detects anti-disassembly device, locates on the circuit substrate, its characterized in that includes:
the anti-disassembly structure comprises a first conductive layer arranged on the circuit substrate, a first signal contact for accessing a Tamper signal and a conductive connecting sheet, and the conductive connecting sheet covers the first signal contact and welds or directly presses the first signal contact;
the coupling conducting strips are arranged on the second conducting layer of the circuit substrate, and each coupling conducting strip is arranged opposite to one anti-dismounting structure to form a coupling capacitor; and
and the detection circuit is connected with the coupling conducting strip and is used for outputting a detection electric signal according to the capacitance change of the coupling capacitor.
2. The capacitively coupled sensing tamper-evident device of claim 1, wherein each of the tamper-evident structures further comprises at least one second signal contact electrically isolated from the first signal contact on the first conductive layer, and the conductive connecting pad overlays and either welds or directly presses the first signal contact and the second signal contact.
3. The capacitively-coupled detection tamper apparatus of claim 1, wherein the detection circuit comprises:
the input end of the access circuit is connected with the coupling conducting strip, and the drive voltage is output based on the voltage of the coupling capacitor;
and the control end of the switch tube is connected with the output end of the access circuit, and the switch tube is switched on and off under the driving of the driving voltage so as to output the detection electric signal at the first conduction end or the second conduction end of the switch tube.
4. The capacitively coupled test tamper evident device of claim 3, wherein the access circuit includes a diode and a capacitor, an anode of the diode being an input of the access circuit, a cathode of the diode being connected to one end of the capacitor and being an output of the access circuit, and another end of the capacitor being connected to ground.
5. The capacitively coupled detection tamper resistant device of claim 4, wherein the access circuit further comprises a pull-up resistor or a pull-down resistor, the pull-up resistor or the pull-down resistor connected to the cathode of the diode.
6. The capacitively coupled tamper-evident device of claim 3, wherein the switch tube is an NPN transistor or an NMOS tube.
7. The capacitively-coupled sensing tamper-evident device of claim 2, wherein the tamper-evident structure further comprises a guard signal ring disposed on the first conductive layer, the guard signal ring being electrically isolated around the outside of the first signal contact and the second signal contact, and the guard signal ring being electrically isolated from the conductive connecting pad.
8. The capacitively-coupled test tamper of claim 7, wherein the guard signal ring, the first signal contact and the second signal contact are gold fingers or copper exposed layers disposed on the first conductive layer.
9. The capacitively-coupled test tamper of any of claims 1 to 6, wherein the first conductive layer is a surface layer of the circuit substrate and the second conductive layer is an intermediate layer of the circuit substrate.
10. A POS machine comprising a capacitively coupled detection tamper evident device of any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020403952.9U CN211827459U (en) | 2020-03-25 | 2020-03-25 | Capacitive coupling type detection anti-dismounting device and POS machine |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202020403952.9U CN211827459U (en) | 2020-03-25 | 2020-03-25 | Capacitive coupling type detection anti-dismounting device and POS machine |
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| CN211827459U true CN211827459U (en) | 2020-10-30 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114322727A (en) * | 2021-12-21 | 2022-04-12 | 深圳市恒辉达电子有限公司 | Equipment anti-disassembly detection device and detection method |
| WO2023215087A1 (en) * | 2022-05-05 | 2023-11-09 | Applied Materials, Inc. | Rf measurement from a transmission line sensor |
-
2020
- 2020-03-25 CN CN202020403952.9U patent/CN211827459U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114322727A (en) * | 2021-12-21 | 2022-04-12 | 深圳市恒辉达电子有限公司 | Equipment anti-disassembly detection device and detection method |
| CN114322727B (en) * | 2021-12-21 | 2024-04-02 | 深圳市恒辉达电子有限公司 | Equipment anti-disassembly detection device and detection method |
| WO2023215087A1 (en) * | 2022-05-05 | 2023-11-09 | Applied Materials, Inc. | Rf measurement from a transmission line sensor |
| US12061215B2 (en) | 2022-05-05 | 2024-08-13 | Applied Materials, Inc. | RF measurement from a transmission line sensor |
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