Ics LLC

United States of America As Represented by the Administrator of Nasa

Gary K Maki

Sterling R Whitaker

Lowell H Miles

Jody Gambles

A SEU tolerant structure has two logic sections that generate two output signals that are complementary such that a fault which affects one section cannot affect the other section. Adjacent NMOS regions or adjacent PMOS regions contain no logic inversions in the combinational logic or if logic inversions in the combinational logic are present where all gates following the inversion are SEU hard by design. The circuits can be realized using one of a Complex CMOS gate, pass transistor logic, Multiplexor logic, AND-OR logic or OR-AND logic. A SRL latch is formed of three NMOS and PMOS structures having a first latch with a first NMOS structure adjacent a first PMOS structure, a second latch with a second NMOS structure adjacent a second PMOS structure wherein the first and second NMOS structures are adjacent one another, and a third latch with a third NMOS structure adjacent a third PMOS structure wherein the second and third PMOS structures are adjacent one another, wherein the latch is adapted to have alternating logic with a state assignment of 010 and 101. A Single Event Upset Triple Modular Redundancy (TMR) tolerant circuit generates complementary output values 010 and 101 with layouts that are adjacent.

Self restoring logic structures

Self Restoring Logic (SRL) provides for SEU tolerance in high speed circuits. An SRL cell is designed to be stable in one of two internal states. Upon an SEU event, the SRL cell will not transition between the internal stable states and recover from an SEU. SRL circuits are realized with SRL storage cells driving succeeding SRL storage cells directly or through combinational logic such that the corruption of any one internal state variable in the driving SRL cell and it's the associated combinational output logic can affect at most one internal state variable of the succeeding SRL cell. An SRL circuit does not allow propagation of single SEU faults.

Self restoring logic

A diagnosable structured logic array and associated process is provided. A base cell structure is provided comprising a logic unit comprising a plurality of input nodes, a plurality of selection nodes, and an output node, a plurality of switches coupled to the selection nodes, where the switches comprises a plurality of input lines, a selection line and an output line, a memory cell coupled to the output node, and a test address bus and a program control bus coupled to the plurality of input lines and the selection line of the plurality of switches. A state on each of the plurality of input nodes is verifiably loaded and read from the memory cell. A trusted memory block is provided. The associated process is provided for testing and verifying a plurality of truth table inputs of the logic unit.

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Coeur d'Alene, ID, United States of America

Gary K Maki