Enhanced leakage characterization and management for electronic circuits

Abstract

The electronic system (100) may include an electronic module (126) and a trace circuit (150) providing a perimeter surrounding the electronic module (126). A sensing circuit (102) within the electronic system (100) may be configured to detect a discontinuity in the perimeter. In response to detecting the discontinuity in the perimeter, the sensing circuit (102) may initiate a response signal from a response device (120).

Description

Background Art

[0001] The present invention relates generally to electronic systems. In particular, the present invention relates to electronic systems configured to detect discontinuities in a perimeter surrounding an electronic module.

[0002] Printed circuit boards (PCBs) can be used to mechanically support and electrically connect electronic components using conductive paths or signal traces etched from copper sheets laminated onto non-conductive substrates. In the manufacture of PCBs, multiple copper / insulation layer pairs (also called "cores") can be laminated together. The number and arrangement of cores can be designed to suit the needs of various applications.

[0003] Vertical interconnect structures (vias) can be used to interconnect conductive signal traces between various conductive layers within a PCB. Copper shapes or areas can be used to distribute power and ground to components mounted on a PCB. Interconnect structures in a PCB can be designed to be physically and electrically compatible with components that can use the PCB interconnect.

[0004] Flexible printed circuits, also called "flex circuits" or "flex cables," are generally understood to be similar to PCBs that can be bent. However, in practice, the set of design rules (e.g., conductor width and spacing) used to design and manufacture flexible circuits can differ significantly from the design rules used in the design and manufacture of rigid or semi-rigid PCBs. In some applications, the conductors of the flexible circuit can be manufactured using processes such as photoimaging or laser imaging as a pattern definition method rather than a "printing" process.

[0005] Flexible printed circuits include a layer of metal traces, typically copper, bonded to a dielectric layer such as polyimide. The thickness of the metal layer can vary from very thin, such as less than 0.0001", to very thick, such as greater than 0.010", and the dielectric thickness can similarly range between 0.0005" and 0.010". The metal can be bonded to the substrate using an adhesive material or other type of bonding (such as vapor deposition). Because copper is susceptible to oxidation in the presence of air, exposed copper surfaces are typically covered with a protective layer. Gold or solder are common materials used for this purpose because of their conductivity and environmental durability. For non-contact or non-conductive areas, a dielectric material can be used to protect the circuit from oxidation or electrical shorts. Electrical leakage (i.e., current leakage) can occur through dielectric materials located between adjacent metal layers. Summary of the invention

[0006] Embodiments may be directed to an electronic system. The electronic system includes an electronic module, a trace circuit that provides a perimeter surrounding the electronic module, and a sensing circuit. The sensing circuit is configured to detect a discontinuity in the perimeter. The sensing circuit is also configured to initiate an action from a response device in response to the detection.

[0007] Embodiments may also be directed to a method for designing an electronic system for managed battery life and managed electronic data security for an electronic module. The method includes receiving design requirements for the electronic system and characterizing dielectric materials that are candidates in the electronic system. The method also includes selecting a dielectric material from the candidate dielectric materials based on the design requirements, and designing a trace circuit to include the selected dielectric material. The method also includes manufacturing a trace circuit based on the trace circuit design, and integrating the trace circuit into the electronic system. Integrating the trace circuit into the electronic system includes surrounding the electronic module with the trace circuit to provide a perimeter surrounding the electronic module, and electrically interconnecting the trace circuit to the sensing circuit.

[0008] Embodiments may also be directed to a method for operating an electronic system for managed battery life and managed electronic data security for an electronic module. The method includes applying a voltage to a trace circuit configured to provide a perimeter surrounding the electronic module with a sensing circuit, and measuring a sensed voltage on the trace circuit with the sensing circuit. The method also includes comparing the sensed voltage to a voltage threshold to detect a discontinuity in the perimeter, and initiating an action in response to the sensed voltage indicating a discontinuity in the perimeter with a response device electrically interconnected to the sensing circuit.

[0009] The above summary of the present invention is not intended to describe each illustrated embodiment or every implementation of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings included herein are incorporated into and form a part of the specification. The accompanying drawings illustrate embodiments of the present invention and together with the description are used to explain the principles of the present invention. The accompanying drawings are only illustrations of certain embodiments and are not intended to limit the present invention.

[0011] Figure 1 An electronic system configured for managed battery life and electronic data security according to an embodiment of the present invention is shown.

[0012] Figure 2 It is a description based on Figure 1 A flow chart of a method for designing an electronic system for managed battery life and electronic data security according to an embodiment of the present invention.

[0013] Figure 3 Including according to and attached Figure 1 FIG. 1 is a graph depicting dielectric leakage measurements of two dielectric materials according to an embodiment of the present invention.

[0014] Figure 4 Including according to and attached Figure 1 A graph depicting the change of a sense voltage on a trace circuit according to an embodiment of the present invention.

[0015] Figure 5 It is a description based on Figure 1 A flowchart of a method for operating an electronic system for managing battery life and electronic data security according to an embodiment of the present invention.

[0016] The present invention may have various modifications and alternative forms, and its details are shown by way of example in the accompanying drawings and will be described in detail. However, it is to be understood that its purpose is not to limit the present invention to the specific embodiments described. On the contrary, the present invention covers all modifications, equivalents and substitutions that fall within the scope of the present invention.

[0017] Throughout the drawings and detailed description, like numbers generally refer to like components, parts, steps, and processes. DETAILED DESCRIPTION

[0018] Certain embodiments of the present invention can be understood in the context of providing discontinuous detection in the perimeter of the electronic module in the electronic device (e.g., server), which can be used to provide data to the client attached to the server through a network. The server can include but is not limited to a web server, an application server, a mail server, and a virtual server. Although not necessarily limited to this, the embodiments discussed in this context can facilitate understanding of various aspects of the present invention. Certain embodiments can also be directed to other devices and associated applications, such as providing discontinuous detection in the perimeter of the electronic module in the computing system, which can be used in various computing and data processing applications. The computing system can include but is not limited to supercomputers, high performance computing (HPC) systems, and other types of special computers. Embodiments can also be directed to providing discontinuous detection in the perimeter of the electronic module in the consumer and small office / home office (SOHO) electronic devices (such as personal computers, laptop computers, mobile and network server devices).

[0019] For ease of discussion, the term "FR" is used herein to refer to a class of flame retardant (Fire Retardant) fiberglass epoxy laminates. FR materials, especially FR4, are widely and commonly used to construct various printed circuit boards (PCBs). FR4 is designed for high-density multi-layer PCBs and is suitable for high-volume fine-line / multi-layer applications. Similarly, the term "AP" is generally used herein to refer to a class of binderless / high-performance laminates, which include all-polyimide composites of copper-clad laminates and polyimide films bonded to copper foil. This material can be used to construct multi-layer flexible and rigid-flexible applications that require advanced material properties, temperature resistance, and high reliability. The term "HT" is generally used herein to refer to a class of high-temperature laminates, characterized by favorable material and electrical properties. Compared to materials such as FR4, the material may have a higher glass transition temperature (Tg) and lower loss characteristics (such as loss tangent).

[0020] The need to store secure / confidential data and include cryptographic functionality in electronic systems has led to the implementation of various devices and techniques to detect and respond to unauthorized tampering attempts on such systems. Potentially vulnerable systems may include, but are not limited to, computers, servers, supercomputers, personal computers, networks, and telecommunications systems. Tampering with such systems may result in unauthorized access to confidential and / or sensitive information, such as financial, military or classified data, sensitive personal identification information (PII), or cryptographic keys.

[0021] Trace circuits including one or more layers of conductive traces fabricated in a serpentine arrangement can be used to detect attempts to invasively tamper with electronic devices and modules. Attempts to tamper (i.e., drill, cut, etc.) with the trace circuits can provide a detectable indication of such tampering, such as an electrical interruption. A responsive device such as a processor or other circuit can then respond to the detected tampering in a variety of ways to warn and / or mitigate security risks.

[0022] Electrical structures such as flexible circuits and / or PCBs including serpentine traces may exhibit significant leakage between adjacent trace layers and / or power distribution layers, particularly when the serpentine traces are arranged in adjacent parallel plane orientations. In some applications, a data / password security system including one or more trace circuits may be powered by an internal battery. Leakage from adjacent trace circuits to other trace circuits and / or power distribution boards may actually shorten the life of the battery powering the security system. This reduction in battery life may compromise the security of data within the system.

[0023] Embodiments of the present invention are directed to systems for monitoring trace circuit continuity within an electronic system such as a computer, server, supercomputer, or network system. The continuity monitoring system includes a trace circuit that serves as a perimeter around an electronic module and can provide an indication of discontinuity of the perimeter. Embodiments include trace circuits constructed with one or more dielectric materials that are characterized, selected, and designed into the trace circuits to manage and minimize leakage current. The managed dielectric leakage current is particularly useful in extending and improving the operating life of a battery that powers the trace circuit continuity monitoring system, which can result in enhanced and extended security of sensitive electronically stored data and encryption keys / data. The enhanced security can result in managed and minimized loss of sensitive / confidential data and / or encryption capabilities.

[0024] Various aspects of the present invention are useful for monitoring the continuity of trace circuits configured to provide a security perimeter to an electronic system. This monitoring can provide enhanced security for electronic storage data and encryption keys within the system. An electronic system configured according to an embodiment can monitor the continuity of the trace circuit while consuming less energy and providing extended battery life relative to other such electronic security systems. An embodiment can be configured to respond to detected tampering / violation of the security perimeter of an electronic system by sending a warning message, activating an alarm or visual indicator, and destroying security / confidential data and / or encryption keys. These actions are useful in enhancing the security of the electronic data within the electronic system.

[0025] Embodiments of the present invention may also be used to reduce energy consumption of a security monitoring system by reducing dielectric leakage and the resulting RC time constant (τ) of one or more trace circuits within the system. A reduction in τ is particularly useful in reducing the response time of a sensing circuit, which may reduce the complexity and energy consumption of such sensing circuits. A reduction in dielectric leakage may also allow for a reduction in trace circuit resistance.

[0026] Various aspects of the present invention are useful in allowing sensing circuits to be probed using commonly available / available voltmeters and / or oscilloscopes with high input impedance. Embodiments of the present invention may also be used to manage electronic system design costs and complexity while using existing and proven PCB design methods and material sets. Electronic systems designed according to certain embodiments may be compatible with existing and proven computer, server, supercomputer and personal computer (PC) designs and PCB / flexible circuit design methods and material sets. An electronic perimeter security monitoring system constructed according to embodiments of the present invention may be installed within an existing electronic device housing.

[0027] Certain embodiments are directed to an electronic system configured to provide managed battery life and electronic data security for an electronic module and to initiate an action when a discontinuity around a perimeter of the electronic module is detected. Figure 1 Included are consistent diagrams 100 , 125 , 150A, and 150B depicting an electronic system and trace circuit 150 for managing battery life and electronic data security according to embodiments of the present invention.

[0028] Diagram 100 can provide an understanding of an electronic system including multiple instances of trace circuits 150, sensing circuits 102, and response devices 120. According to an embodiment, the sensing circuits 102 are electrically interconnected to the trace circuits 150 and are configured to monitor the continuity of the trace circuits 150. In response to the sensing circuits 102 detecting a discontinuity within the trace circuits 150, the response device 120 can initiate an action designed to warn and / or mitigate a data security condition / problem within the electronic system 100, 125. In this embodiment, the electronic system 100 functions as a data security system.

[0029] It will be appreciated that the electronic systems 100, 125 can be integrated into various electronic devices and systems, such as computers, servers, special computers, supercomputers, and personal computers (PCs). The system can rely on monitoring of trace circuit continuity to ensure robust, continuous data security. In some embodiments, the electronic system 100 can be used as a cryptographic security system. Specific component arrangements and interconnection mechanisms are depicted in Figures 100, 125, and many variations of these mechanisms including components depicted and described herein are possible. Embodiments are useful in providing accurate sensing and timely response to the destruction of the perimeter of the electronic system. Such sensing and timely response are particularly useful in preventing and issuing warnings about unauthorized access to secure data and / or encryption keys stored on the electronic system.

[0030] According to an embodiment, the trace circuit 150 may include one or more conductive serpentine traces consistent with the signal traces formed on the flexible circuit, which can be used to detect perimeter discontinuities. For example, attempting to cut, drill, or otherwise damage the perimeter provided by the cover 128 surrounding the electronic module 126 may cause discontinuities in the trace circuit 150. In the case of such an action, a perimeter discontinuity 158 may be generated, i.e., FIG. 150A. When the perimeter discontinuity 158 is generated in response to an attempt to damage / violate the perimeter formed by the trace circuit 150, relatively close conductor spacing (e.g., 4 mils) within the serpentine traces 156A, 156B may be particularly useful. Resistance (e.g., R1, R2, and / or R3) can be sensed by the sensing circuit 102 and used as an indicator of the continuity of the trace circuit 150.

[0031] In an embodiment, the trace circuit 150 includes a dielectric material 154 located between and in conductive contact with two conductive layers 152A, 152B, and the two conductive layers 152A, 152B serve as electrical terminals. According to an embodiment, the two conductive layers 152A, 152B can each be a planar structure, such as a power plane of a PCB or a flexible circuit. According to an embodiment, the trace circuit 150 can be a portion of one or more flexible circuits that at least partially surround the electronic module 126 within the electronic system 100, 125. Similarly, in some embodiments, the trace circuit 150 can represent a portion of a PCB that at least partially surrounds the electronic module 126, and Figure 100 shows three trace circuits 150 electrically interconnected in a series configuration.

[0032] In some embodiments, the electronic module 126 can be a cryptographic module, and the perimeter provided by the trace circuit 150 can be a security perimeter around the cryptographic module. In this embodiment, the sensing circuit 102 can be configured to detect attempted violations of the security perimeter. According to an embodiment, the placement of the trace circuit(s) 150 attached to or adjacent to the inner surface of the cover 128 can allow the trace circuit 150 to function as a security perimeter around or partially around the electronic module 126. The security perimeter is particularly useful in detecting attempted tampering at various locations.

[0033] The resistors R1, R2, and R3 of the trace circuit 150 (combined with the resistor R, electrically connected to the detection circuit 102, the sense grid 112, and ground (GND)) act as a voltage divider circuit. When the series-connected trace circuits 150 are interconnected in this circuit, the continuity of the series-connected trace circuits 150 (Figure 100, as represented by the resistors R1, R2, and R3) can be measured by using the sense circuit 102 to measure the sense voltage V on the sense grid 112. S to be sure.

[0034] According to an embodiment, the sensing circuit 102 is configured to provide an applied voltage V to the voltage divider circuit described above. A In the presence of continuity across each trace circuit 150 , the sense voltage V sensed at the sense net 112 of the sense circuit 102 S Will be V A *(R1+R2+R3) / (R+R1+R2+R3). In the event of a discontinuity in any one of the trace circuits 150, the sense voltage V S will be approximately V A , for example, ≈V DD The values ​​of R, R1, R2, and R3 may be selected so that the V generated by the continuity across each trace circuit 150 is S and V generated by any discontinuity of the trace circuit 150 SThis difference in VS value can be detected by the sensing circuit 102 and converted into an output voltage V O According to an embodiment, the sensing circuit 102 may include, for example, a comparator configured to convert the voltage V O The sense circuit 102 may be converted to a logic signal, i.e., a logic "0" or "1" value. The signal may be used to indicate to the responding device 120 the complete continuity across all serially connected trace circuits 150 or a perimeter discontinuity (e.g., 158). In some embodiments, the sense circuit 102 may be configured to continuously sense the continuity of the trace circuit 150, and in some embodiments, the sense circuit 102 may be configured to periodically sense the continuity of the trace circuit 150.

[0035] According to an embodiment, the electronic system 100 can include any number of trace circuits 150 in a series connection configuration, as depicted, in order to provide a robust perimeter surrounding the electronic module 126 within the cover 128. For example, in some embodiments, the electronic system 100 can include a single trace circuit 150, two trace circuits 150, or three or more trace circuits 150. The sensing circuit 102 is depicted as an example circuit; other types of sensing circuits 102 are also possible. In an embodiment, the functionality of the sensing circuit 102 can be relatively simple to implement as discrete components or into an existing or new IC, such as an application specific integrated circuit (ASIC).

[0036] In some embodiments, the output 104 may be a single analog or digital signal line. In some embodiments, the sensing circuit 102 may include additional components not shown that are configured to convert the output voltage V O Converted into other types of signals, for example, representing the output voltage V O In a corresponding embodiment, the output 104 may include, for example, a signal configured to convert V O Represents a conductor that transmits a high-speed serial signal such as a Universal Serial Bus (USB) signal.

[0037] The response device 120 is electrically connected to the sensing circuit 102 through the output 104 to receive the output voltage V O According to an embodiment, the response device 120 may include, but is not limited to, a processor circuit, a service processor, an electronic module 126, and a network connection device. In some embodiments, the response device 120 is configured to respond to the output voltage V OIndicating a lack of continuity (e.g., discontinuity 158) (diagram 150A in trace circuit 150), an action is initiated. According to an embodiment, the action may include, but is not limited to, sending a message, such as a text message, a system console message, or a short message service (SMS) message, to alert a system user or technician of the discontinuity of the perimeter around the electronic module 126. In some embodiments, the action may also include illuminating an indicator such as a light emitting diode (LED), sounding an audible alarm, and / or deleting an encryption key within the electronic module 126. One or a combination of the above actions may be used to protect the security of data and / or encryption keys included within the electronic module 126.

[0038] According to an embodiment, electronic system (side cutaway view) 125 may be used to provide a visual understanding of the interconnection and arrangement of components within electronic systems 100, 125. The functionality, electrical characteristics, and interconnections of electronic system 125 are consistent with those described above with reference to electronic system 100. Figure 125 is particularly useful in describing the structure, arrangement, and electrical interconnection relationship between electronic module 126, cover 128, trace circuit 150, connector 136, PCB 138, and response device 120.

[0039] According to an embodiment, the electronic module 126 can be configured to store and / or process sensitive or secure electronically stored data. The electronic module 126 can include an IC 130, such as a processor, a memory device, an ASIC, and a cryptographic chip, which are mounted and electrically interconnected on a PCB 134. The sensing circuit 102 can be powered by a battery (e.g., 132), which can enable it to provide continuous detection of perimeter discontinuities (e.g., 158) of the trace circuit 150 in the event that the electronic module 126 is disconnected from the electronic system power supply. The connector 136 provides electrical interconnection between the electronic module 126 and other components and / or devices within the electronic system 125, for example, from the sensing circuit 102 to the output 104 of the response device 120 mounted on the PCB 138. According to an embodiment, the PCB 138 can be a component of a computer, a supercomputer, a server, a PC, or other electronic system. In some embodiments, the electronic module 126 can be a cryptographic module.

[0040] The electronic module 126 may be enclosed by a cover 128, which may be designed to prohibit visual inspection and physical access to the electronic module 126. According to an embodiment, the trace circuit 150 may be connected to the (one or more) inner surfaces of the cover 128 using, for example, an adhesive or other bonding agent or technique. In an embodiment, a designer may select a dielectric layer (e.g., 154) based on material property data to meet electronic system design requirements. These requirements may include, for example, maximum dielectric leakage specifications. Using a dielectric layer (e.g., 154) with controlled and / or reduced leakage characteristics is particularly useful in reducing the power consumption of the electronic system 100, and thereby increasing and extending the life of the battery 132 used to power the electronic system 100.

[0041] The use of the trace circuit 150 may help provide cost-effective detection of unauthorized physical access to sensitive data and / or encryption keys stored on the electronic module 126. The trace circuit 150 may also be particularly useful in managing and reducing leakage between the conductive layers 152A and 152B, which may provide a managed and enhanced operating life of the battery 132. Example dielectric material types that may be used for the dielectric layer 154 of the trace circuit 150 may include, but are not limited to, FR, HT, and AP laminate material layers. According to an embodiment, the conductive layers 152A and 152B of the trace circuit 150 may include serpentine traces 156A, 156B, respectively, that serve as a perimeter surrounding the electronic module 126. Depending on the PCB design and material settings, the conductive layers 152A and 152B may include copper and / or other types of metals.

[0042] According to embodiments, the serpentine traces may have various patterns, such as 156A, 156B, as depicted in FIG. 150A. The trace circuit 150 may include one or more conductive layers, such as 152A, 152B. In some embodiments, the conductive layers (e.g., 152A, 152B) are electrically insulated from each other by a dielectric layer (e.g., 154). In an embodiment, the trace circuit 150 includes a dielectric layer 154 located near both (i.e., between) the conductive layers 152A and 152B. The trace circuit 150 may include a single conductive layer (e.g., 152A), and in some embodiments, the trace circuit 150 may include two or more conductive layers (e.g., 152A and 152B), as shown. In embodiments, various types of adhesives and / or bonding agents may be used to bond the trace circuit 150 to the inner surface of the cover 128. Reference numeral 158 is depicted as a flexible circuit in FIG. 150, however, in some embodiments, 158 may alternatively represent a PCB. In some embodiments, the flexible circuits or PCBs may be electrically interconnected by soldering to form a perimeter around multiple sides (eg, top, bottom, and sides) of the electronic module 126 .

[0043] Figure 1 as well as Figure 1The components depicted in the drawings do not necessarily represent the actual size of the components or subcomponents used alone or together in the embodiments. They do not necessarily represent the actual or relative size of any device, component, or subcomponent. Instead, they are intended to describe how each subcomponent of the electronic system is arranged relative to other subcomponents according to embodiments of the present invention.

[0044] Figure 2 It is a description based on Figure 1 A method for designing for managed battery life and electronic data security in accordance with the present invention Figure 1 Flowchart of method 200 for electronic systems 100, 125. Execution of method 200 is useful in designing an electronic system that can provide reliable, cost-effective, and energy-efficient data security monitoring and corrective action response for use with electronic systems such as computers and servers. In association with the operating electronic system, method 200 can provide improved energy efficiency and battery operating life for the electronic system. In some embodiments, electronic system 100 can be a cryptographic security system.

[0045] From start 202, method 200 moves to operation 204. Operation 204 generally involves managing battery life and electronic data security receipt. Figure 1 According to an embodiment, the design requirements may include, for example, Figure 1 The trace circuit 150 (which crosses Figure 1 The design requirements may include, for example, a specified maximum voltage drop, energy loss, and RC time constant (τ) across the conductive layers of the dielectric 150. The design requirements may also include a battery (e.g., Figure 1 132) minimum operating life, the battery is configured to Figure 1 The electronic system 100 is powered. In some embodiments, the minimum operating life of the battery may be specified by a published cryptographic security specification (eg, the U.S. Government Federal Information Processing Standard (FIPS) 140-2 Security Requirements for Cryptographic Modules).

[0046] Depending on the embodiment, each of these requirements may need to be met in order to meet the overall design requirements of the electronic system. In an embodiment, a circuit designer or an electronic design automation (EDA) system may receive the design requirements from a specification document or file. The document or file may be in the form of, for example, a printed copy or an electronic file. The electronic file may be in a variety of formats, such as a word processing document, a text file, a spreadsheet file, or a proprietary or non-proprietary specification file.

[0047] It is understood that various electronic systems may have different design requirements. For example, one type of electronic system (e.g. Figure 1 The electronic module 126 may be portable and / or at least partially dependent on battery power and require a relatively small maximum dielectric leakage. In some embodiments, the electronic module 126 may be a cryptographic module. In contrast, another type of electronic system may not rely on battery power at all, may have a trace circuit 150 that is specified to be more compatible with a particular sensing circuit 102 design, and may have a larger specified leakage current. After receiving the design requirements, the method 200 moves to operation 206.

[0048] Optional operation 206 generally involves characterizing Figure 1 Candidate dielectric and bonding dielectric materials within the electronic system 100, 125 of the present invention may be characterized. The dielectric materials may include, for example, sheets of dielectric material having a metal (e.g., copper) coating on one or both sides of the dielectric and various bonding dielectric materials. According to an embodiment, candidate dielectric and bonding materials may be characterized to provide PCB and circuit designers with parameters useful in making design decisions and tradeoffs. For example, the dielectric material may be subjected to various frequencies applied to a conductive plate on a planar surface of the material, and the resulting losses may be recorded. Figure 3 is an example graph of measured loss versus frequency for two dielectric materials, FR and HT. According to an embodiment, characterizing the candidate dielectric and adhesive may include characterizing leakage characteristics of the candidate dielectric and adhesive materials, including temperature-dependent leakage variations. In an embodiment, the candidate dielectric and adhesive materials may include, but are not limited to, FR, HT, and AP materials.

[0049] The above characterization can be performed, for example, by a supplier or vendor of dielectric materials, a circuit or PCB designer, or an independent laboratory. Such characterization can be performed at one or more temperatures of interest, such as an expected maximum operating temperature, or across an operating temperature range in an electronic system. After characterizing the candidate dielectric and adhesive materials, method 200 moves to operation 208.

[0050] Operation 208 generally involves selecting characterized dielectric and bonding materials according to the design requirements received in operation 204. According to an embodiment, the designer selects dielectric and bonding materials from a number of characterized dielectric and bonding materials, such as FR, HT, and AP dielectric materials. In some embodiments, dielectric materials and complementary dielectric materials can be combined to take advantage of the electrical and / or physical properties of the two materials. One or more dielectric materials can be selected based on the properties of individual materials and materials combined in proportions of various properties. These properties can include, for example, temperature-dependent leakage and loss characteristics, dielectric constants, and bonding properties. According to an embodiment, selecting dielectric materials according to design requirements can include selecting dielectric materials with characteristic leakage less than a specified leakage value. In some embodiments, dielectric materials can be selected based on characteristic leakage that varies less than a specified amount over an operating temperature range. The selection of dielectric materials can be performed in conjunction with an analysis of the output from an EDA program (e.g., a field solver or other electrical simulation program).

[0051] In some embodiments, an inherently long serpentine trace (e.g. Figure 1 of 156A) can lead to a trace circuit ( Figure 1 The relatively large RC time constant (τ) of the trace circuit 150). Large values ​​of τ can result in Figure 1 The sensing circuit 102 has too much settling time, and causes the battery (eg Figure 1 132) energy consumption. Figure 1 Current leakage across dielectric layer 154 can also be used to increase τ.

[0052] According to an embodiment, selecting dielectric and bonding materials characterized by reduced leakage according to the design requirements received in operation 204 may be particularly useful in reducing dielectric current leakage, and thus reducing τ. Reducing the value of τ may improve Figure 1 The response time of the sensing circuit 102 and Figure 1 of the battery 132. According to an embodiment, this reduction in dielectric leakage can span a range of electronic system operating temperatures. In an embodiment, selecting a characterized dielectric can include, for example, selecting a HT dielectric material over a FR dielectric material. Other selections can be made within the scope of the invention.

[0053] In some embodiments, for example, selecting a characterized dielectric and bonding material with lower dielectric leakage can reduce τ by approximately 50%. Due to the reduced leakage, the trace circuit resistance can be reduced by a factor of 5 to produce an overall power saving that can increase the battery operating life by approximately 10%. In some applications, this improvement in operating life can produce an additional 6-9 months of battery-powered operation.

[0054] In addition to the benefit of reduced power consumption, reducing leakage current through dielectric material selection also enables detection of significantly higher trace resistances, thereby allowing the trace circuit to be probed with a commonly available voltmeter or oscilloscope having an input impedance in the range of 1 MΩ to 10 MΩ. According to an embodiment, the sensing circuit 102 may not need to have a hysteresis input characteristic, thereby further reducing sensing circuit complexity and power consumption.

[0055] Selecting dielectric materials based on characterized leakage is essential for managing the leakage from serpentine traces (e.g. Figure 1 156A) to another serpentine trace (e.g. Figure 1 156B) or to another layer (such as a power or ground distribution layer). This managed leakage can result in a device that is configured to provide power to an electronic module (such as Figure 1 The electronic module 126 in the embodiment of the present invention is powered by a battery (e.g. Figure 1 After selecting the characterized dielectric and bonding materials, method 200 moves to operation 210.

[0056] Operation 210 generally involves designing the trace circuit to include the characterized dielectric and bonding materials selected in operation 208. According to an embodiment, designing the trace circuit may include selecting a specific plane pair in the PCB or flexible circuit design that meets the volume / amount of the characterized dielectric material that meets the dielectric leakage design requirements. The characterized dielectric material may include a combination of dielectric material and supplementary dielectric material. In some embodiments, more than one plane pair may be used, and in some embodiments, an EDA program, such as a field solver or other type of electrical simulation program, may be used during the design process. After designing the trace circuit, method 200 moves to operation 212.

[0057] Operation 212 generally refers to fabricating a trace circuit according to the trace circuit design completed in operation 210. According to an embodiment, Figure 1 The trace circuit 150 can be manufactured according to the design of operation 210. In some embodiments, Figure 1 The trace circuit 150 can then be bonded to other PCB and / or flexible circuit layers. The various lamination, etching, drilling and other process steps used in operation 212 are generally consistent with existing PCB and / or flexible circuit manufacturing and assembly processes. After the trace circuit is manufactured, the method 200 moves to operation 214.

[0058] Operation 214 generally involves converting, for example, Figure 1 The 150 trace circuit is integrated into Figure 1In an electronic system 100, 125. According to an embodiment, the integration may include placing and connecting one or more trace circuits 150 to the inner surface of the cover 128 so as to surround and enclose the electronic module 126 with a perimeter. In some embodiments, the perimeter is a security perimeter around a cryptographic module, and the sensing circuit 102 is configured to detect an attempted violation of the security perimeter. Various types of adhesives and / or bonding techniques may be used during the connection process. According to an embodiment, the integration may also include electrically interconnecting one or more trace circuits 150 in series, such as Figure 1 Integration may also include electrically interconnecting the trace circuit 150 to the sensing circuit 102, such as by soldering connections to the connector 136 and conductors in the PCB 134. After the trace circuit is integrated into the electronic system, the method 200 may end at operation 216.

[0059] Figure 3 It is a description based on Figure 1 Graph of dielectric leakage measurements as a function of frequency for two dielectric materials of a consistent embodiment. The dielectric materials may be used in layers, such as Figure 1 The dielectric layer 154 of the embodiment may be included in the trace circuit 150. Characterization may include various such dielectric materials, including but not limited to FR, HT, and AP dielectric layers. Characterization and measurement of properties such as dielectric leakage may give the PCB designer valuable insight into which dielectric material or combination of dielectric materials to select for a particular application.

[0060] Figure 3 The data plots provided in can provide a visual understanding of the cause-effect relationship between measurement frequency and dielectric leakage, as well as the relative differences in leakage between various types of dielectric materials. Figure 3 The vertical axis corresponds to the leakage of FR and HT type dielectric materials, measured in dB; higher values ​​or positions on the vertical axis correspond to higher leakage values. Figure 3 The horizontal axis at the bottom corresponds to the frequency (kHz) at which the leakage measurement is made. As an example, the range of the vertical axis can span from about -92 dB at the bottom to -70 dB at the top. Similarly, the range of the horizontal axis can span from about 0 kHz to 1.0 kHz. The leakage measurement can be made at various temperatures, such as 25°C, 85°C, or 100°C.

[0061] It can be observed that the FR dielectric curve 302 and the HT dielectric curve 304 have significantly different leakage. For example, at the maximum measurement frequency ( Figure 4 ), the leakage difference between the FR dielectric curve 302 and the HT dielectric curve 304 is shown to be approximately 13 dB, corresponding to a 20-fold difference in power loss between the FR and HT dielectric materials. Measurements on other dielectric material types may produce other relative results. Figure 3The characterization of dielectric material properties such as leakage shown in is particularly useful for providing an understanding of the electrical characteristics of various dielectric material types, which can be used to select between dielectric material types to include in the trace circuit 150 design.

[0062] Figure 4 It is based on the Figure 1 The embodiment of the present invention includes two graphs 400 and 450, which depict, for example, Figure 1 The sensing voltage V of the trace circuit 150 S The sensing voltage change can be made by dielectric materials (such as Figure 1 The dielectric material 154 of the trace circuit 150 may be included in the trace circuit 150. These materials may include, but are not limited to, FR, HT, and AP dielectric layers. Characterization of dielectric materials can give PCB designers valuable insight and understanding as to which dielectric material or combination of dielectric materials to select for a particular trace circuit application. Selecting dielectric materials with minimal leakage is important in managing and / or minimizing the impact of electronic modules (e.g., Figure 1 126) is particularly useful in reducing electrical leakage and improving battery life.

[0063] Figure 4 The data graphs provided in the table can provide information on the measured temperature and sense voltage V S The causal relationship between the sensing voltage V and the use of various types of dielectric materials S Visual understanding of the relative difference(s). Figure 4 The temperature curve 402 on the vertical axis corresponds to the measured temperature of the FR and HT type dielectric materials, measured in C; higher values ​​or positions on the vertical axis correspond to higher measured temperatures. Figure 4 The voltage curves 404A and 404B on the vertical axis correspond to the V of the FR and HT type dielectric materials measured within the temperature range of the temperature curve 402, respectively. S (measured in volts). Higher values ​​or positions on the vertical axis correspond to higher V S Voltage curve 404B represents the sensed voltage (eg, V S ), whose dielectric leakage can be largely independent of operating temperature. Figure 4 The bottom horizontal axis corresponds to the time when the sense voltage measurement is made. As an example, the vertical axis of the temperature curve 402, i.e., T MIN -T MAX , can be from about -15℃ T MIN Spanning to about 75°C T MAX .

[0064] It can be observed that the FR dielectric curve 402 and the HT dielectric curve 404 have significantly different sense voltages V corresponding to different temperature-dependent leakages. S Changes. Figure 4 As shown, by measuring the sense voltage V S Characterizing dielectric materials is particularly useful for providing an understanding of the electrical properties of various dielectric material types that may be used to select between dielectric material types to include in a trace circuit 150 design.

[0065] Figure 5 It is a description based on Figure 1 The embodiment of the present invention is used for operating Figure 1 The electronic system 100, 125 is used for Figure 1 Flowchart of method 500 for managed battery life and electronic data security of electronic module 126 of FIG. Implementation of method 500 is useful in providing robust data security for an electronic system and data included in the system while enhancing the battery ( Figure 1 The effective operating life of the battery 132).

[0066] From start 502, method 500 moves to operation 504. Operation 504 generally involves using sensing circuit 102 to Figure 1 The voltage V A Apply to Figure 1 According to an embodiment, Figure 1 The trace circuit 150 may be configured to provide a perimeter surrounding the electronic module 126 and may include a plurality of trace circuits connected in series, such as Figure 1 The trace circuit may be located, for example, adjacent to the top, bottom, or side of the cover 128. In some embodiments, the electronic module 126 may include a portion of the electronic system 100, 125, which is a cryptographic security system including a cryptographic module. The cryptographic module may include, but is not limited to, a cryptographic coprocessor, a cryptographic accelerator, a cryptographic adapter card, a cryptographic field programmable gate array (FPGA), and a memory that stores cryptographic accelerator data.

[0067] In some embodiments, the trace circuit(s) 150 may be fabricated as a flexible circuit, and in some embodiments, the trace circuit(s) 150 may be fabricated as a PCB. Figure 1 The voltage V applied by the sensing circuit 102 A It can be, for example, V DDor another voltage selected by the circuit designer. In some embodiments, operation 504 may also include heating the trace circuit(s) 150 to a known or "reference" temperature. Such heating may be used to detect small temperature changes, or to "normalize" the temperature of the trace circuit 150 to be compatible with the sensing circuit 102. A After being applied to the trace circuit, the method 500 moves to operation 506 .

[0068] Operation 506 generally involves using Figure 1 The sensing circuit 102 measures Figure 1 The sense voltage V across one or more trace circuits 150 S According to an embodiment, if each trace circuit 150 has continuity, ie, across resistors R1, R2, and R3, then a corresponding sense voltage V will be present at the sense network 112 indicating continuity. S For example, if the values ​​of resistors R1, R2, and R3 are relatively small compared to the value of resistor R, the sense voltage V S The corresponding value of will be approximately 0V.

[0069] At least one trace circuit 150 (eg, resistor R1, R2, or R3) has a discontinuity (eg, Figure 1 158), indicating a discontinuous corresponding sensing voltage V S , for example ≈V A , will appear at the sensing network 112. According to an embodiment, the discontinuity may be understood to represent the Figure 1 The trace circuit 150 is around Figure 1 An attempted violation of the security perimeter formed by the electronic module 126. When measuring the sense voltage V S Afterwards, method 500 moves to operation 508 .

[0070] Operation 508 generally involves using the sensing circuit 102 to Figure 1 The sensing voltage V received at the sensing network 112 S According to an embodiment, the sensing voltage V S Used as one or more serpentine traces (e.g. Figure 1 156A) of the perimeter discontinuity. Figure 1 158) may be caused by an unauthorized attempt to tamper with the cover 128 around the electronic module 126. According to an embodiment, the sensing circuit 102 can be a comparator, an operational amplifier (op-amp), or other type of comparison and / or amplifier circuit, which can be implemented with discrete components or integrated in an IC such as an ASIC.

[0071] According to an embodiment, the sensing circuit 102 may be configured to sense the voltage V S is compared with a threshold value, which is used to set the V corresponding to the continuity of the trace circuit(s) 150 S and V corresponding to a discontinuity in at least one (plural) trace circuit 150 S For example, in some embodiments, the threshold voltage may be V A / 2. Following this example, the measured V S Less than the threshold indicates crossing Figure 1 The continuity of the trace(s) of circuit 150 while measuring the V S Greater than the threshold indicates crossing Figure 1 After the output voltage is compared to the voltage threshold, the method 500 moves to operation 510 .

[0072] In operation 510, Figure 1 The sensing circuit 102 determines the sensing voltage V received by the sensing circuit 102 on the sensing network 112 S According to an embodiment, for example, if V S is less than the voltage threshold, it can be determined that there is no discontinuity in any (one or more) trace circuits 150. S If the sense circuit 102 is greater than the voltage threshold, it can be determined that there is a discontinuity in at least one trace circuit 150. According to an embodiment, the sense circuit 102 can be configured to drive the output voltage V with a logic "0" or logic "1" value corresponding to the continuity or discontinuity of the sensed (one or more) trace circuits 150. O In some embodiments, the sensing circuit 102 may be configured to amplify the sensing voltage V S In order to drive the output voltage V O If Figure 1 The sensing voltage V received at the sensing network 112 S No discontinuity is indicated, the method 500 returns to operation 504. Figure 1 The sensing voltage V received at the sensing network 112 S If a discontinuity is indicated, the method 500 moves to operation 512 .

[0073] Operation 512 generally refers to responding to an indication of a discontinuity in at least one trace circuit 150 by Figure 1 The response device 120 initiates the action. According to an embodiment, the response device 120 may be, for example, a processor circuit, a service processor, a network connection device, an electronic module (e.g. Figure 1 126) or other electronic devices. The response device 120 includes receiving the output voltage V from the output 104O circuit / function, and responds to V O Indicates a discontinuity and initiates one or more response actions. For example, Figure 1 The sensing circuit 102 may output an output voltage V indicating a discontinuity in at least one trace circuit 150 to the response device 120. O , for example, by V DD Indicated by a logical "1". According to an embodiment, in response to receiving the signal, the response device 120 may perform an action, or may communicate with another device to initiate an action, such as a computer, a processor, an IC, or a network-connected or other electrically interconnected device. For example, the response device 120 may initiate an action, such as sending a message, sounding an alarm, or deleting an encryption key within the electronic module 126. According to an embodiment, the message sent may include, but is not limited to, an email notification, an SMS notification, or a system console message. The alarm may include a visual or audible alarm, such as lighting an indicator such as an LED or a light, or activating a buzzer, a horn, a siren, etc. Within the scope of the present invention, other types of perimeter discontinuities ( Figure 1 158) instructions are also possible.

[0074] Some embodiments of the present invention may allow for detection and reaction to attempted, unauthorized inspections of cryptographic modules or devices. Embodiments of the present invention may provide indications of attempted physical intrusion inspections of security or cryptographic circuits without imposing permanent and / or negative impacts on the device or functionality of the circuit in which the circuit is deployed. After the action is initiated, method 500 returns to operation 504.

[0075] The description of various embodiments of the present invention is given for the purpose of illustration, but it is not intended to be exhaustive or limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope of the described embodiments. The terms used herein are selected to explain the principles of the embodiments, practical applications, or technical improvements existing in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

[0076] In a preferred embodiment of the present invention, a method for designing an electronic system for managed battery life and managed electronic data security of an electronic module is provided, the method comprising: receiving design requirements for the electronic system; characterizing dielectric materials as candidates for use in the electronic system; selecting a dielectric material that meets the design requirements from the candidate dielectric materials; designing a trace circuit to include the selected dielectric material; manufacturing the trace circuit according to the trace circuit design; and integrating the trace circuit into the electronic system by the following steps: surrounding the electronic module with the trace circuit to provide a perimeter surrounding the electronic module; and electrically interconnecting the trace circuit to a sensing circuit. Preferably, the electronic system is a cryptographic security system; the electronic module is a cryptographic module; the perimeter is a security perimeter around the cryptographic module; and the sensing circuit is configured to detect an attempted violation of the security perimeter; the electronic system design requirements include a minimum operating life of a battery configured to power the electronic system. The minimum operating life of the battery configured to power the electronic system is preferably specified by a published cryptographic security specification. Characterizing the candidate dielectric material preferably includes characterizing leakage characteristics of the candidate dielectric material, including temperature-dependent leakage variations. The candidate dielectric material preferably includes a material selected from the group consisting of a bonding dielectric material and a sheet of encapsulated dielectric material. The method preferably also includes selecting a supplemental dielectric material based on design requirements, and wherein the design of the trace circuit includes the dielectric material and the supplemental dielectric material. Selecting the dielectric material based on the design requirements preferably includes selecting a dielectric material having: a characterized leakage less than a specified leakage value; and a characterized leakage that varies less than a specified amount over an operating temperature range. The design of the trace circuit preferably includes specifying an amount of dielectric material and supplemental dielectric material that results in leakage of the trace circuit less than a leakage threshold.

Claims

1. An electronic system comprising: Electronic modules; a cover surrounding the electronic module; A trace circuit connected to the inner surface of the cover and providing a perimeter surrounding the electronic module, wherein the trace circuit includes a dielectric material located between conductive layers, the dielectric material having: A characterized leakage current that is less than a specified leakage current value; and Characterized leakage that varies less than a specified amount over the operating temperature range, wherein the trace circuit further comprises a supplemental dielectric material, and the amounts of the dielectric material and the supplemental dielectric material are specified to result in a leakage of the trace circuit being less than a leakage threshold; and A sensing circuit is configured to: detecting a discontinuity in the perimeter; and In response to the detection, an action is initiated from the responding device.

2. The electronic system according to claim 1, wherein: The electronic system is a password-secured system; The electronic module is a cryptographic module; The perimeter is a security perimeter surrounding the cryptographic module; as well as The sensing circuit is configured to detect an attempted violation of a security perimeter.

3. The electronic system according to claim 1, wherein: The action of signaling a discontinuity in the perimeter is selected from the group consisting of: deleting an encryption key in the electronic module, sending an email notification, sending a short message service (SMS) notification, illuminating an indicator, and sounding an audible alarm.

4. The electronic system according to claim 1, wherein: The sensing circuit is configured to detect a discontinuity in the perimeter by detecting a resistance of the trace circuit indicative of the discontinuity in the perimeter.

5. The electronic system according to claim 1, wherein: The trace circuit is manufactured as a flexible circuit.

6. The electronic system according to claim 1, wherein: The responding device is selected from the group consisting of: a processor circuit, a service processor, an electronic module, and a networking device.

7. The electronic system according to claim 1, wherein: The perimeter of the trace circuit includes a first conductive serpentine trace.

8. The electronic system according to claim 7, wherein: The trace circuit includes a second conductive serpentine trace electrically insulated from the first conductive serpentine trace by a dielectric layer.

9. A method for operating an electronic system for managed battery life and managed electronic data security of electronic modules, the method comprising: A voltage is applied using a sensing circuit to a trace circuit configured to provide a perimeter surrounding an electronic module, the trace circuit being connected to an inner surface of a cover surrounding the electronic module, and the trace circuit comprising a dielectric material between conductive layers, wherein the dielectric material has: A characterized leakage current that is less than a specified leakage current value; and Characterized leakage that varies less than a specified amount over the operating temperature range; wherein the trace circuit further comprises a supplementary dielectric material, and the amounts of the dielectric material and the supplementary dielectric material that cause the leakage of the trace circuit to be less than a leakage threshold are specified; measuring a sensed voltage on the trace circuit using the sensing circuit; comparing the sensed voltage to a voltage threshold to detect a discontinuity in the perimeter; and In response to the sensed voltage indicating the discontinuity in the perimeter, an action is initiated using a response device electrically interconnected to the sensing circuit.

10. The method according to claim 9, wherein: The electronic system is a cryptographically secure system; The electronic module is a cryptographic module; The responsive device is selected from the group consisting of: an electronic module, a processor circuit, a networking device, and a service processor; The perimeter is a security perimeter surrounding the cryptographic module; as well as The sensing circuit is configured to detect an attempted violation of the security perimeter surrounding the cryptographic module.

11. The method according to claim 10, wherein: The action of signaling a discontinuity in the perimeter is selected from the group consisting of: deleting an encryption key in the electronic module, sending an email notification, sending a short message service (SMS) notification, illuminating an indicator, and sounding an audible alarm.

12. The method according to claim 9, wherein: The trace circuit is manufactured as a flexible circuit.

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