A radiation resistant voting circuit

Reliability means and radiation resistance of digital equipment. For aerospace computer systems is extremely urgent to develop radiation-resistant components. One way to ensure the radiation resistance is the creation of a special architecture — RHBD (Radiation Hardened by Design). This approach includes triple redundancy (Triple Modular Redundancy — TMR) to reduce radiation-induced switching of logic elements (Single Event Transients — SET) and memory elements (Single Event Upset — SEU). FPGA due to the large number of elements configuration memory is not vulnerable to the effects of radiation. Therefore, one-time programmable devices are used, for example, the companies Actel, but flip-flops tripled too. Nevertheless, in the SRAM configurable FPGA Virtex (Xilinx) used triple redundancy with Majority Vote Circuit based on a tristate buffer instead LUT. Such Voter has implementation features that are explored in the article. One of the variants of majority voter for the pins of the FPGA using a minority voting function. Only in this case, no conflict of signals at the outputs of buffers. Describes CMOS implementation of the voters. The paper proposes a fault tolerant CMOS implementation of the Majority Voter and Minority Voter in order to improve reliability and FPGA radiation resistance.