Design exploration of majority voter architectures based on the signal probability for TMR strategy optimization in space applications

Abstract

Hardware redundancy is a well-known fault tolerance technique used in safety-and mission-critical systems. However, the hardening efficiency of such techniques relies on the robustness of the majority voter circuitry. This summary provides the design exploration of majority voter architectures to be used in radiation environments such as in space missions. An application-specific Single-Event Transient (SET) characterization based on the signal probability is proposed to optimize the Triple-Modular Redundancy (TMR) block insertion methodologies. Results show that the SET cross-section of complex-gate architectures presents low input dependence while for the NOR/NAND based architectures a higher dependence is observed due to the logical masking effects. Additionally, different from the other architectures, the NAND voter has shown a reduction in the SET rate as the signal probability is increased. Considering the signal probability p = 0.1, p = 0.5 and p = 0.9, the best design for the two analyzed orbits is the NOR, CMOS1 and NAND voter, respectively.

Tradeoffs in Time-to-Digital Converter Architectures for Harsh Radiation Environments

“…The final output voters will always remain a sensitive circuit and can by definition not be triplicated. These circuits need to be hardened through dedicated logic implementation [26], transistor sizing, the use of dummy devices for charge sharing [27], filtering and intelligent exploitation of the pulse quenching effect [28].…”

A High-Reliability Redundancy Scheme for Design of Radiation-Tolerant Half-Duty Limited DC-DC Converters

“…To ensure radiation tolerance, different methods have been proposed and are actually being used in space [1][2][3][4][5][6][7][8][9][10][11][12]. Using radiation-hardened devices or fault-tolerant designs are the most common methods.…”

“…Electronics 2021, 10, 1146 2 of 19 N Modular Redundancy (NMR) uses N copies of a module, where N is usually odd, with a voting system to tolerate faults in up to (N − 1)/2 modules. Triple Modular Redundancy (TMR) is currently widely used to mitigate radiation-induced faults and is considered to have "saved" several space missions [1][2][3][4][5][6][7][8][9][10][11][12].…”