Analysis and Mitigation of Multiple Radiation Induced Errors in Modern Circuits

Author

Adam Watkins, Southern Illinois University CarbondaleFollow

Date of Award

12-1-2016

Degree Name

Doctor of Philosophy

Department

Electrical and Computer Engineering

First Advisor

Tragoudas, Spyros

Abstract

Due to technology scaling, the probability of a high energy radiation particle striking multiple transistors has continued to increase. This, in turn has created a need for new circuit designs that can tolerate multiple simultaneous errors. A common type of error in memory elements is the double node upset (DNU) which has continued to become more common. All existing DNU tolerant designs either suffer from high area and performance overhead, may lose the data stored in the element during clock gating due to high impedance states or are vulnerable to an error after a DNU occurs. In this dissertation, a novel latch design is proposed in which all nodes are capable of fully recovering their correct value after a single or double node upset, referred to as DNU robust. The proposed latch offers lower delay, power consumption and area requirements compared to existing DNU robust designs. Multiple simultaneous radiation induced errors are a current problem that must be studied in combinational logic. Typically, simulators are used early in the design phase which use netlists and rudimentary information of the process parameters to determine the error rate of a circuit. Existing simulators are able to accurately determine the effects when the problem space is limited to one error. However, existing methods do not provide accurate information when multiple concurrent errors occur due to inaccurate approximation of the glitch shape when multiple errors meet at a gate. To improve existing error simulation, a novel analytical methodology to determine the pulse shape when multiple simultaneous errors occur is proposed. Through extensive simulations, it is shown that the proposed methodology matches closely with HSPICE while providing a speedup of 15X. The analysis of the soft error rate of a circuit has continued to be a difficult problem due to the calculation of the logical effect on a pulse generated by a radiation particle. Common existing methods to determine logical effects use either exhaustive input pattern simulation or binary decision diagrams. The problem with both approaches is that simulation of the circuit can be intractably time consuming or can encounter memory blowup. To solve this issue, a simulation tool is proposed which employs partitioning to reduce the execution time and memory overhead. In addition, the tool integrates an accurate electrical masking model. Compared to existing simulation tools, the proposed tool can simulate circuits up to 90X faster.