Fault-tolerant TMR and DMR circuits with latchup protection switches

Keywords: Single event effect Fault tolerance Triple and double modular redundancy Latchup protection switch ASIC design a b s t r a c t The paper presents CMOS ASICs which can tolerate the single event upsets (SEUs), the single event transients (SET), and the single event latchup (SEL). Triple and double modular redundant (TMR and DMR) circuits in combination with SEL protection switches (SPS) make the base of the proposed approach. The SPS had been designed, characterized, and verified before it became a standard library cell. A few additional steps during logic synthesis and layout generation have been introduced in order to implement the redundant net-lists and power domains as well as to place the latchup protection switches. The approach and accompanying techniques have been verified on the example of a shift-register and a middleware switch processor. Malfunctions of electronic devices due to the single event effects, being an effect of radiation, are observed not only in cosmic and airborne equipment, but also in mainstream applications. Together with the progressing integration and scaling of the electronic chips their susceptibility to errors increases. The current space microelectronics development and high energy physics research require shorter design time and cheaper solutions for the radiation and fault tolerant ASIC designs [1–3]. The main idea is to provide ASICs capable of correct and reliable functioning in the radiation environment using the standard semiconductor technologies and design flow. Therefore, the design of the advanced fault-tolerant digital integrated circuits needs scientific research and progress concerning three important aspects: a. Analysis of irradiation effects and circuit faults. b. Development of fault models and simulation test benches. c. Design of fault-tolerant circuits and systems. Definition and description of the basic irradiation effects and fault mechanisms can be found in the literature [4–6]. The thesis referenced in [7] provides an overview of different radiation environments and investigates interaction mechanisms between energetic particles and the matter. It also introduces a new semi-empirical model for estimating the electronic stopping force of heavy ions in solids. The most common irradiation effect is a single event effect (SEE) induced by a cosmic particle strike. Three common types of SEE are known: single event upset (SEU), single event transient (SET) and single event latchup (SEL). A single event upset causes the change of state in a storage element. It affects the memory cells and sequential logic. A single effect transient causes a short impulse …