Dual path redundancy with stacked transistor voting
First Claim
1. A method of radiation hardening a section of combinational logic circuitry comprising upstream logic coupled to a logic gate, the logic gate receiving a first input signal, and the logic gate comprising a first Field Effect Transistor (FET), the first FET having a gate, a source, and a drain, the method comprising:
- coupling the first FET to a second FET, the second FET having a gate, a source, and a drain, the drain of the first FET coupled to the drain of the second FET so as to create a voter FET, the source of the first FET being a source of the voter FET, and the drain of the second FET being a drain of the voter FET; and
duplicating the first input signal so as to create a second input signal, the gate of the first FET coupled to receive the first input signal, and the gate of the second FET coupled to receive the second input signal.
1 Assignment
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Accused Products
Abstract
A method of operation and an apparatus for radiation hardening a combinational logic circuit are presented. A section of logic that is to be radiation hardened is identified. An entire logic circuit or a portion of the logic circuit may be radiation hardened. Once the section of logic is identified, a Field Effect Transistor (FET) is duplicated so as to create a voter FET. The voter FET is coupled with an original node (or signal) and a duplicated node (or signal). If a radiation event strikes either the original node or the duplicated node, the voter FET will prevent an upset from propagating to down stream logic by preventing a conduction path through the voter FET. Additionally, all of the circuitry that was duplicated in order to create the duplicated node may also undergo a radiation event without causing an upset to propagate to downstream logic.
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Citations
26 Claims
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1. A method of radiation hardening a section of combinational logic circuitry comprising upstream logic coupled to a logic gate, the logic gate receiving a first input signal, and the logic gate comprising a first Field Effect Transistor (FET), the first FET having a gate, a source, and a drain, the method comprising:
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coupling the first FET to a second FET, the second FET having a gate, a source, and a drain, the drain of the first FET coupled to the drain of the second FET so as to create a voter FET, the source of the first FET being a source of the voter FET, and the drain of the second FET being a drain of the voter FET; and
duplicating the first input signal so as to create a second input signal, the gate of the first FET coupled to receive the first input signal, and the gate of the second FET coupled to receive the second input signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of operating a radiation hardened logic circuit, the logic circuit comprising a dual input voter Field Effect Transistor (FET), the voter FET comprising first and second FETs, the first and second FETs each having a gate, a source, and a drain, the drain of the first FET coupled to the source of the second FET, the gate of the first FET being a first input of the voter FET, and the gate of the second FET being a second input of the voter FET, the method comprising:
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duplicating an original signal within the logic circuit so as to create a duplicated signal, the original signal being on a first duplicated node, and the duplicated signal being on a second duplicated node;
biasing the first input of the voter FET with the original signal;
biasing the second input of the voter FET with the duplicated signal;
opening a conduction path between the drain and the source of the voter FET; and
when a radiation event occurs on one of the duplicated nodes, closing the conduction path between the drain and the source of the voter FET. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A radiation hardened logic gate, the logic gate comprising:
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first and second p-type Field Effect Transistors (pFETs) each having a gate, a source, and a drain, the drain of the first pFET coupled to the source of the second pFET so as to create a first voter pFET, the source of the first pFET being the source of the first voter pFET, the drain of the second pFET being the drain of the first voter pFET, and the gates of the first and second pFETs being respective first and second inputs of the first voter pFET; and
first and second n-type Field Effect Transistors (nFETs) each having a gate, a source, and a drain, the drain of the first nFET coupled to the source of the second nFET so as to create a first voter nFET, the source of the first nFET being the source of the first voter nFET, the drain of the second nFET being the drain of the first voter nFET, the gates of the first and second nFETs being respective first and second inputs of the first voter nFET, and the drain of the first voter nFET coupled to the drain of the second voter pFET. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26)
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Specification