Redundancy circuits hardened against single event upsets

Abstract

A decision block is incorporated into a circuit design to provide hardening against single event upset and to store data. The decision block includes a storage element that stores data as long as inputs to the decision block remain constant. The decision block receives a first data input and second data input from redundant logic blocks or from logic blocks designed to provide complementary outputs. The decision block provides an output that is at a same logic level as the first data input if the two data inputs are at expected logic levels during normal operating conditions (i.e., no disturbances). The decision block provides an output that is at a same logic level as a previous output of the decision block if the two data inputs are not at expected logic levels during normal operating conditions.