Patent Application
20220392854
The present disclosure relates to integrated circuits, and more particularly to integrated circuits that are configured to reliably fail applicable radiation tolerance tests.
Most integrated circuits (ICs) are intended for terrestrial use in environments that are not subject to radiation exposure beyond what is normal at the earth's surface. There are, however, some applications in which ICs must be “radiation hardened” so that they will function reliably in a high radiation environment, such as in space, or proximal to nuclear reactors. There are several strategies that can be employed to radiation harden an IC design. These include adjusting dimensions and other features of the IC design to minimize radiation effects, providing radiation shielding, and/or including fault-tolerance features in the IC such as redundancy and/or error correction.
Radiation hardened ICs are often useful for supporting government regulated activities, including incorporation of the ICs into certain military and surveillance systems. As such, foundries that produce radiation hardened ICs, referred to herein as “radiation certified” foundries, are subject to special governmental controls, scrutiny, and other requirements, including extensive reporting and documentation requirements, as well as secrecy requirements. Radiation hardened ICs are also frequently subject to export restrictions.
So as to distinguish between ICs that are deemed to be “radiation hardened” and those that are not, governments typically issue regulations that specify a set of radiation tolerance tests and corresponding tolerance thresholds, wherein separate radiation tolerance tests and thresholds are used to measure the sensitivity of an IC to each of several different characteristics of radiation exposure. For example, separate tests and tolerance thresholds may be defined for total radiation dosage, neutron flux, single event charged particle impacts, dose rate, and single event upsets. In each case, an IC will be deemed to pass a radiation tolerance test if it does not fail when exposed to an amount of radiation that meets or exceeds the associated tolerance threshold. The regulations further divide ICs into categories according to their functions and other factors, and specify which of the tests are applicable to each category of IC. Accordingly, in general, special restrictions and requirements as specified in the regulations will apply to an IC that falls in a given category if and only if it passes one or more of the radiation tolerance tests that are “applicable” to that type of IC.
Radiation tolerance tests and tolerance thresholds that are applicable to integrated circuits manufactured in the United States are specified in the International Traffic in Arms Regulations (ITAR) and the Export Administration Regulations (EAR). Examples of such tests include total ionizing dose (TID)≥500 Krds, prompt dose≥5×108 rads(Si)/sec, neutron dose≥1×1014 n/cm2, and/or Single Event Upset (SEU)≤1×10−10 errors/bit-day (Heavy Ion). As an example, EAR 3A001.a.1 imposes export limitations on integrated circuits that can withstand i.e. continue to function, after exposure to any one of the following radiation thresholds:
For IC manufacturers that do not wish to be radiation certified, because they wish to avoid the special requirements and restrictions that apply to radiation certified foundries, it can therefore be important that all of the ICs that they manufacture will reliably fail all of their applicable radiation tolerance tests.
As used herein, an IC's “applicable radiation tolerance tests” refers to the radiation tolerance tests that are defined in one or more government regulations, such as ITAR and EAR, and are specified in the regulations to apply to the category to which the IC belongs. ICs that reliably fail all of their applicable radiation tolerance tests are referred to herein as “radiation intolerant” ICs, while ICs that reliably pass at least one of their applicable radiation tolerance tests are referred to herein as “radiation tolerant” ICs. Radiation tolerant ICs that meet more stringent, application specific radiation tolerance requirements, in addition to passing their applicable radiation tolerance tests, are referred to herein as “radiation hardened” ICs.
Generally, radiation hardened ICs are required to meet a set of stringent, “real world” requirements based on engineering considerations, so that the IC will be suitable for implementation in a specified high radiation environment, such as in space. As such, radiation hardened ICs will also be radiation “tolerant,” in that they can be expected to pass most or all of the less stringent, applicable radiation tolerance tests that are specified in government regulations such as EAR and ITAR.
On the other hand, ICs that are not intended to be used in high radiation environments can fail the applicable radiation tolerance tests by a considerable margin, and still be suitable for exposure to the very low radiation levels that are present at the earth's surface.
Of course, IC designs that are intended to fail their applicable radiation tolerance tests will generally not include any special radiation tolerant features, such as shielding or wide critical node spacing. Nevertheless, some of the recent advances in semiconductor processes that have been adopted to improve the performance of microprocessors and other ICs have also tended to increase the radiation tolerance of some types of ICs. For example, modern ICs that operate at lower voltages, and that implement smaller transistors with thinner oxide layers, tend to be much less susceptible to radiation than their counterparts produced just a few years ago. Thus, there is a possibility that some modern IC designs, while intended only for terrestrial, civilian use, may nevertheless inadvertently and unintentionally pass one or more of their applicable radiation tolerance tests.
Accordingly, there is a strong concern among foundries that are not radiation certified that accidental production of ICs that unintentionally pass at least one of their applicable radiation tolerance tests could be deemed to be radiation tolerant, and could thereby subject the foundry to the heightened scrutiny and other requirements that apply to radiation certified foundries. One approach to avoiding this possibility is to test each IC design for radiation tolerance. However, testing an IC to verify that it fails all of its applicable radiation tolerance tests can be expensive and time consuming, and can require specialized testing apparatus. As a result, many IC foundries that are not radiation certified cannot afford to test each new IC design for radiation tolerance. At the same time, it is necessary for many foundries that are not radiation certified to implement the latest improvements in IC design and manufacture, so as to remain competitive in the marketplace.
One approach to avoiding inadvertent production of ICs that may pass an applicable total radiation dosage test is to implement a feature within an integrated circuit design that is specifically intended to disable or cripple the IC, or certain features of the IC, upon exposure to a specified total radiation dosage, thereby causing the IC to reliably fail the applicable total radiation dosage test, while allowing the IC to function normally so long as the total radiation dosage remains below a defined radiation threshold. Typically, such total radiation dosage limiting features include components and circuitry that are configured to detect and/or measure a total radiation dosage, and to issue an IC-disabling signal once a specified total radiation dosage has been received, thereby ensuring that the IC will reliably fail the applicable total radiation dosage tolerance test, even if the IC design would otherwise pass the test.
However, this approach only ensures that the IC will fail total radiation dosage tolerance tests, and does not ensure that the IC will fail any of its other applicable radiation tolerance tests, and thereby does not fully address the concerns of chip foundries that wish to avoid falling under the special requirements and restrictions that apply to radiation certified foundries by producing only radiation intolerant ICs.
What is needed, therefore, is an IC design approach which ensures that ICs intended for civilian, terrestrial use will reliably fail any desired combination of radiation tolerance tests.
The present disclosure is a method of designing ICs which ensures that all of the ICs will reliably fail any desired combination of radiation tolerance tests that are imposed by applicable radiation tolerance standards such as EAR and ITAR.
According to the present disclosure, an IC design includes a “functional section” that may be radiation tolerant, but also includes at least one radiation tolerance limiting feature (RTLF) that is configured to ensure that the IC, as initially manufactured, will reliably fail at least one of its applicable radiation tolerance tests, and preferably all of its applicable radiation tolerance tests. In various embodiments, the RTLF is “triggered” when exposed to a specified type and amount of radiation, referred to herein as a “trigger threshold,” after which it functions to disable the IC, for example by reducing or shorting a required voltage, issuing a reset signal to the functional section, and/or disabling a signal that is required by the functional section, such as a clock signal. By including a plurality of RTLFs, the IC can be designed to fail any desired combination of corresponding radiation tolerance tests.
Embodiments further include one or more “programmable radiation tolerance” (PRT) features that can be actuated at an approved and certified programming center, after initial production of the IC, to disable or bypass the one or more RTLFs, thereby converting the radiation intolerant IC into a radiation tolerant IC. ICs that incorporate one or more RTLF in combination with one or more corresponding PRTs are referred to herein as PRT ICs. ICs that incorporate one or more of the disclosed RTLFs, but do not incorporate any PRT features, are referred to herein as permanently radiation intolerant ICs, or xRAD ICs.
The present disclosure thereby enables foundries that are not “radiation certified,” including the most advanced foundries, to produce the disclosed xRAD ICs and/or PRT ICs in large quantities as radiation intolerant ICs that will reliably fail their applicable radiation tolerance tests, and will therefore be suitable for general use and export. Once a quantity of PRT ICs has been manufactured, some or all of the PRT ICs can then be transferred to a secure, approved and certified programming center that is authorized to produce radiation tolerant ICs, where the PRT features of the ICs can be actuated. This step is referred to herein as “programming” the PRT IC. The resulting radiation tolerant ICs thereby benefit from being manufactured at the most suitable foundry, as well as from the much lower production costs of an IC foundry that is not radiation certified, while incurring only a minor added cost associated with the much simpler, post-manufacturing step of PRT actuation. Embodiments realize a further cost benefit due to economy of scale by producing large quantities of PRT ICs, even if only a subset will subsequently be programmed to be radiation hardened.
Costs of producing the disclosed xRAD and PRT ICs can be even further reduced by developing a library of RTLFs and combined RTLF/PRT “IP cores” that are initially incorporated into test ICs and subjected to thorough radiation exposure testing. If the trigger threshold of an RTLF can be adjusted by changing the values of one or more adjustment components, for example by varying the value of one or more resistors in a voltage divider circuit, the optimal values of the adjustment components can also be determined during this testing phase. For example, the trigger threshold can be adjusted so that it is approximately one half of the tolerance threshold that is specified in an applicable radiation tolerance test. In embodiments, the adjustment components are implemented in the test ICs as variable components, such as variable resistors and capacitors, so that optimal values can be easily determined. Subsequently, fixed components can be substituted for these variable components in the IP core library. After the IP cores have been tested and optimized, they can then typically be incorporated into any new IC design in any desired combination, without requiring additional testing. Based on previous IP core testing conditions and results, an analysis of the new IC design can be applied in each case to indicate whether the selected IP cores can be implemented with confidence, or whether further testing may be needed.
According to the present disclosure, the RTLF and/or PRT features that are included in a PRT IC can be protected from unauthorized actuation by any of several approaches, used either alone or in combination. One such approach is to obfuscate the PRT within the IC design, so that it becomes very difficult to recognize and/or analyze the RTLF and/or PRT based on examination of the lithography mask designs of the IC or analysis of the IC die. As an example, the RTLF and/or PRT can be designed to mimic a different type of circuit, such as an Electrostatic Discharge (ESD) protection circuit, that is commonly included in ICs. Another example is to widely separate different portions of the RTLF and/or PRT at different locations within the IC, so that it becomes very difficult to recognize that the separated portions function together as a RTLF or PRT.
Another approach for preventing unauthorized PRT actuation is to implement one or more of the PRTs in a programmable element, such as a field programmable gate array (FPGA), that is included in the IC design. As originally manufactured, the programmable element can be unprogrammed, or perhaps programmed to perform some other, innocuous task. Subsequent actuation of the PRT then includes reprogramming the programmable element so that it will function to bypass or disable the RTLF.
Still another approach is to include a password recognition circuit in the PRT, such that actuation of the PRT requires input of a password, thereby preventing unauthorized actuation of the PRT. To provide additional protection against unauthorized PRT actuation, the password and/or programming code can be protected from reverse engineering by including cryptographic hashing as part of the decoding function of the IC.
Embodiments implement still other forms of secure integrated circuit design and processing that can incorporate a variety of protection schemes to prevent unauthorized intrusion or modification of the integrated circuit's intended function.
The scope of the present disclosure includes a wide variety of RTLF and PRT approaches. Some exemplary and enabling examples of RTLF and PRT approaches are presented herein. However, the recited RTLF and PRT examples do not limit the scope of the disclosure. Additional variations would readily occur to one of skill in the art in light of the examples presented herein.
In some embodiments of the present disclosure, an RTLF includes a MOSFET, oxide dielectric capacitor, or other “leakage” component or circuit that will be damaged and will develop a leakage current if a voltage is applied across the leakage component while the leakage component or circuit is exposed to radiation. The radiation-induced leakage can be configured to reduce or short a required voltage within the PRT IC or xRAD IC, and/or to short an input to a gate or change the input to a voltage comparator within the IC, for example by forming part of a voltage divider configured such that a change in leakage will cause the voltage divider to change its output state, which serves as an input to a voltage comparator, thereby blocking a required signal within the IC or causing the voltage comparator to issue a disabling logic signal that resets or otherwise disables the IC.
In other embodiments, an RTLF includes a photocurrent generating component that produces a photocurrent in response to a radiation dose rate event. The photocurrent generating component can be implemented as part of a voltage divider that provides an input to a voltage comparator, as described in the previous example.
In yet other embodiments, an RTLF includes at least one “single event upset” (SEU) capture element that is susceptible to radiation-induced SEUs. The SEU capture element is initially forced to a logic zero state by a power-on reset circuit, but transitions to a logic one state when an SEU occurs due to radiation exposure. The output of the SEU capture element can be directed to a comparator or logic gate, to the gate input of a MOSFET that is configured to short a required voltage, and/or to an input of a gate that is configured to block a required signal of the IC.
In various embodiments, a PRT can block, bypass, or otherwise inactivate an RTLF in any of several ways. For example, if the RTLF includes a leakage component, and if the sensitivity of the leakage component to damage by radiation is proportional to a voltage that is applied across the leakage component, the PRT can function to remove the voltage that is applied across the leakage component, thereby virtually eliminating its sensitivity to radiation damage.
In some embodiments where an RTLF includes an SEU capture element, comparator, or other circuit or gate that issues a disabling logic signal when the RTLF is exposed to radiation, the corresponding PRT includes a signal-blocking circuit, such as an OR gate or NAND gate, that is configured to block or ignore the logic signal issued by the RTLF when the PRT is actuated.
In embodiments, the RTLF and/or the PRT include redundancies in their design that minimize any possibility that an RTLF could fail to disable the IC upon exposure to radiation, or that a PRT, when actuated, could fail to disable the corresponding RTLF.
A first general aspect of the present disclosure is an integrated circuit (IC) having intentional radiation intolerance. The IC includes a functionality section, and a radiation tolerance limiting feature (RTLF) that is configured, when it is triggered, to partially or fully disable operation of the functionality section, the RTLF being triggered when it is exposed to radiation that exceeds a specified threshold of a radiation characteristic other than total radiation dosage, the RTLF trigger threshold being low enough to ensure that the IC will fail a radiation tolerance test directed to the radiation characteristic as specified by an applicable regulatory requirement.
In embodiments, the RTLF is obfuscated within the IC design, thereby hindering recognition, and reverse engineering of the RTLF based on examination of lithography mask designs of the IC or analysis of the IC die.
In any of the above embodiments, the trigger threshold can include at least one of a radiation dosage rate threshold, a single event burnout threshold, a neutron flux threshold, a linear energy transfer threshold, a single event charged particle impact threshold, a single event upset threshold a single event latchup threshold, and a single event gate rupture threshold.
In any of the above embodiments, the RTLF can be configured to cause a required voltage of the IC to be reduced when the RTLF is triggered.
In any of the above embodiments, the RTLF can be configured to issue a disabling signal that disables the functional section when the RTLF is triggered.
In any of the above embodiments, the RTLF can include a leakage component or circuit that is configured to develop a leakage when the leakage component or circuit is exposed to radiation while a voltage is applied to the leakage component or circuit. In some of these embodiments, the leakage component or circuit includes at least one of an oxide dielectric capacitor, a radiation-sensitive MOSFET, a radiation-sensitive silicon-controlled rectifier (SCR), and a photocurrent generating component or circuit. And in any of these embodiments, the leakage component can be implemented as part of a voltage divider that directs a leakage voltage to an input of a voltage comparator, and wherein the voltage comparator is configured to compare the leakage voltage with a reference voltage, and to cause the RTLF to be triggered when the leakage voltage transitions from being greater than the reference voltage to being less than the reference voltage, or vice versa.
In any of the above embodiments, the IC can include a plurality of RTLFs, thereby ensuring that the IC will fail a corresponding plurality of applicable radiation tolerance tests.
In any of the above embodiments, the RTLF trigger threshold can be adjustable by changing a value of at least one adjustment component of the RTLF.
In any of the above embodiments, the RTLF trigger thresholds can be adjustable by changing a value of a voltage applied across a radiation sensitive component of the first or second RTLF.
In any of the above embodiments, the IC can include a RTLF testing output that can be monitored without triggering the RTLF to determine whether the RTLF is able to disable the functional section of the IC when it is triggered.
A second general aspect of the present disclosure is an integrated circuit (IC) having intentional radiation intolerance. The IC includes a functionality section, and at least one radiation tolerance limiting feature (RTLF) that is configured to partially or fully disable operation of the functionality section upon a trigger event, wherein the trigger event ensures that the IC will fail a radiation tolerance test, the trigger event comprising one of a radiation dosage rate, a single event burnout, a neutron flux, a linear energy transfer, a single event charged particle impact, a single event upset, a single event latchup, and a single event gate rupture.
The features and advantages described herein are not all-inclusive and, in particular, many additional features and advantages will be apparent to one of ordinary skill in the art in view of the drawings, specification, and claims. Moreover, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes, and not to limit the scope of the inventive subject matter.
The present disclosure is a method of designing ICs which ensures that all of the ICs, as of the time of manufacture, will reliably fail any desired combination of radiation tolerance tests that are imposed by applicable radiation tolerance regulations such as EAR and ITAR. Embodiments also reduce the cost of producing functionally similar or identical radiation hardened ICs that are intended for domestic use in high radiation environments.
With reference to
In the simplified example of
Also included in the disclosed PRT IC 100 is at least one “programmable radiation tolerance” (PRT) feature 106 that initially allows the RTLF to disable the functional section 102, but can be actuated at a secure, certified facility after initial production of the PRT IC 100 to disable or bypass the RTLF 104, thereby causing the PRT IC to become radiation tolerant. This actuation of the PRT 106 is referred to herein as “programming” the PRT IC, and the input 116 that is used to actuate the PRT 106 is referred to as the “programming” input 116. The ability of the PRT 106 to allow or block the action of the RTLF 104 can be implemented in many different ways, and is indicated in
Embodiments further include an alarm signal 124 indicating that the PRT 106 has been actuated, and/or a test signal output 120 that can be monitored to verify that the RTLF 104 has been triggered.
It will be understood that
After the initial manufacture of a batch of PRT ICs 100, some or all of them can then be transferred to a secure facility that is authorized and certified to produce radiation tolerant ICs, where the PRTs 106 can be actuated via their programming input(s) 116, thereby converting the PRT ICs 100 into radiation tolerant ICs. The resulting radiation tolerant ICs 100 thereby benefit from being manufactured at the most suitable foundry, as well as from the much lower production costs of an IC foundry that is not radiation certified, while incurring only a minor added cost associated with the much simpler, post-manufacturing step of PRT actuation. Embodiments realize a further cost benefit due to economy of scale, by producing large quantities of PRT ICs, even if only a subset will subsequently be programmed to be radiation tolerant.
In the simple example of
However, when the PRT 106 is actuated via the programming input 116, so that the logic signal 114 is logic 0, the AND gate 108 will apply a logic 0 to the reset 110 regardless of the status of the RTLF 104 and the disabling signal 112, thereby enabling the PRT IC 100 to function as a radiation tolerant IC. In embodiments, actuation of the PRT 106 is accomplished by applying a suitable voltage across specified pins of the PRT IC 100, in a manner similar to programming a “programmable read only memory” (PROM).
With reference to
It is notable that the RTLFs 104 that are disclosed herein are not limited to only ensuring that the IC will fail total radiation dosage tolerance tests. Instead, ICs are disclosed herein that incorporate RTLFs 104 that will ensure that the IC will fail any desired combination of one or more of its applicable radiation tolerance tests.
Due to the incorporation of the RTLF 104, the disclosed PRT IC 100 or xRAD IC 122 can therefore be produced in large quantities by IC foundries that are not radiation certified, and will be suitable for general use and export, because the PRT ICs 100 or xRAD ICs 122, as initially manufactured, will fail their applicable radiation tolerance tests, and will be deemed to be radiation intolerant ICs.
According to the present disclosure, any combination of the RTLF 104 and/or PRT 106 features that are included in a PRT IC 100 or xRAD IC 122 can be protected from unauthorized actuation or reverse engineering by any of several approaches, used either alone or in combination. With reference to
With reference to
With reference to
With reference to
In embodiments, the uploaded programming code of the programmable element 316 of
There are a number of other secure designing and processing technologies that incorporate anti-tamper protection schemes on integrated circuits to prevent unauthorized tampering or access that are implemented in embodiments of the present application, as will be known to one of skill in the art.
The scope of the present disclosure includes a wide variety of RTLF 104 and PRT 106 approaches. Some examples of RTLF 104 and PRT 106 approaches are presented in the drawings and described herein that are exemplary and enabling. Included among the illustrated examples are RTLF 104 approaches that will render the IC, as manufactured by the foundry, intolerant to at least one of, total radiation dosage, events over a Linear Energy Transfer (LET) level (e.g. via gate rupture), Single Event Latchup (SEL), radiation dose rate, and Single Event Upset (SEU). However, the RTLF 104 and PRT 106 examples recited herein do not limit the scope of the disclosure. It should also be noted that the terms “RTLF” and “PRT” refer to functionalities of the PRT IC 100 or xRAD IC 122. In various embodiments, the RTLF 104 and PRT 106 of a PRT IC 100 are partially or entirely blended into a single element, circuit, or “IP core.”
It should be noted that
With reference to
In similar embodiments, a separate leakage voltage that is not otherwise required for operation of the functionality section 102 of the PRT IC 100 is applied across the leakage component 400, which in some embodiments can be adjusted so as to adjust the radiation sensitivity of the RTLF 104.
In the example of
However, subsequent to the manufacturing of the PRT IC 100, if the programming input 116 is programmed to logic 0, then the p-channel MOSFET 402 will conduct, while the n-channel MOSFET 404 will not conduct. As a result, +V will not be applied across the oxide dielectric capacitor 400. This will cause the oxide dielectric capacitor 400 to be virtually unaffected by radiation exposure. Furthermore, even if the oxide dielectric capacitor 400 were to develop leakage due to radiation exposure, current would be unable to flow through the n-channel MOSFET 404, and for that reason no additional current load would be placed upon +V.
The ability of the programming input 116 to reliably deactivate the RTLF 104 can be verified by confirming that when the programming signal is set to logic 0, the test output 120 is at +V, indicating that no voltage is applied across the leakage component 400.
With reference to
Similarly, embodiments include redundant RTLFs 104 configured so that triggering of any one of them will disable the functional section 102, so long as none of the PRTs 106 has been actuated.
With reference to
With reference to
With reference to
With reference to
The PRT 106 in this example comprises a NOR gate 512 that receives the disabling signal 112 together with a programming signal 116. The output of the NOR gate 512 is directed as a control signal 118 to a reset input 110 of the functional section 102. Upon initial manufacture, the programming signal 116 is set to logic 0, such that the reset output 118 follows the inverse of the disabling signal 112. Before exposure to radiation, the disabling signal 112 is logic 1, causing the control signal to be logic 0, thereby allowing the functionality section 102 to operate normally. When the PRT IC 100 is exposed to sufficient radiation to cause the leakage voltage 502 to drop below the reference voltage 510, then the disabling signal 112 transitions to logic 0 and the control signal 118 transitions to logic 1, thereby deactivating the functionality section 102.
However, if the programming signal 116 is programmed to logic 1 after the initial manufacture of the PRT IC 100, then the control output of the NOR gate 118 will be held at logic 0, thereby allowing the functionality section 102 to operate normally, regardless of the status of the leakage component 400 and disabling signal 112.
The variable resistors 500, 508 in the example of
Redundancy can be added to the example of
With reference to
With reference to
The example embodiment of
The programming signal 116 is initially set to logic 0, causing the n-channel MOSET 404 to be “off” (non-conducting) while the p-channel MOSFET 402 is “on” (conducting), thus biasing the parasitic SCR 600 to near +V. In this bias condition, the parasitic SCR 600 is trigged during radiation exposure by a charged particle physically traversing through its sensitive region, resulting in a single event latch-up (SEL) condition. This causes the leakage voltage 502 to drop below the reference voltage 510, so that the disabling signal output 112 of the voltage comparator 504 transitions to logic 0, which in turn causes the control signal 118 to transition to logic 1. The net result is that the functional section 102 of the PRT IC 100 is disabled.
When the programming signal 116 is set to logic 1, this causes the n-channel MOSFET 404 to be “on” (conducting) and the p-channel MOSFET 402 to be “off” (non-conducting), thereby biasing the parasitic SCR 600 to near ground. In this bias condition, the parasitic SCR 600 is incapable of being triggered by a charged particle physically traversing through its sensitive area, because the SCR circuit 600 is inoperative when no voltage is applied to it. Furthermore, the control signal 118 of the NOR gate 512 is forced remain in logic 0 state regardless of the status of the parasitic SCR 600 and the disabling signal 112.
In any of the embodiments of
In the example embodiment of
If any one or more of the SEU components undergoes a SEU event, then the output of the SEU capture circuit 702 transitions to logic 1, causing the reset output 118 to transition to logic 1. At the same time, n-channel MOSFET 704 is caused to conduct, thereby connecting +V to ground, thereby further disabling the functionality section 102. The embodiment of
When the programming signal 116 is set to logic 0, then the reset output 118 is forced to logic 0 regardless of the status of the SEU capture circuit 702. At the same time, MOSFET 706 is blocked from conducting, thereby ensuring that +V is not connected to ground.
As noted above,
While redundancy is only illustrated in
It should further be noted that the RTLF 104 examples presented in
With reference to
However, some or all of the batch of PRT ICs 100 are diverted to a secure actuation center 1204 that is licensed and certified to produce radiation tolerant ICs. At the secure actuation center, the PRT features 106 of the PRT ICs 100 are actuated 1206, thereby nullifying the RTLF features 104 of the PRT ICs 100, and converting the PRT ICs 100 into radiation tolerant ICs that can be implemented 1208 in military and other approved applications (e.g. civilian satellite applications) as needed.
The foregoing description of the embodiments of the disclosure has been presented for the purposes of illustration and description. Each and every page of this submission, and all contents thereon, however characterized, identified, or numbered, is considered a substantive part of this application for all purposes, irrespective of form or placement within the application. This specification is not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Many modifications and variations are possible in light of this disclosure.
Although the present application is shown in a limited number of forms, the scope of the disclosure is not limited to just these forms, but is amenable to various changes and modifications. The disclosure presented herein does not explicitly disclose all possible combinations of features that fall within the scope of the disclosure. The features disclosed herein for the various embodiments can generally be interchanged and combined into any combinations that are not self-contradictory without departing from the scope of the disclosure. In particular, the limitations presented in dependent claims below can be combined with their corresponding independent claims in any number and in any order without departing from the scope of this disclosure, unless the dependent claims are logically incompatible with each other.
This application is a continuation in part of U.S. application Ser. No. 17/340,807, filed Jun. 7, 2021, which is herein incorporated by reference in its entirety for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17340807 | Jun 2021 | US |
| Child | 17742925 | US |
