Studies On Random Logic Online Testing And Fault Tolerant Structures

Online-testing and fault-tolerant (OLTFT) structures are widely used in computer reliability engineering. However, they are various from each other.The most popular used OLTFT structures are dual modular redundancy with comparison (DMRC), including complementary logic, triple modular redundancy (TMR), retry, alternating logic (AL), etc. Alternating-complementary logic (ACL) and complementary logic-alternating complementary logic (CL-ACL) based on complementary logic and alternating logic, are presented recently. In this paper, we analyze the hardware complexity and fault response rate of the OLTFT structures mentioned above by using experiments.This paper presents integrated circuit (IC) test methods at first. A novel method for the construction of self-dual circuits, which is essential in alternating logic, is proposed based on the original method of constructing self-dual circuits. Compared with the original one, the novel method can dramatically decrease the extra area cost of chips. Then, CL-ACL structure is improved, simulation and verification under real gate delay is done. Then, we use ISCAS85 benchmark circuits as the circuits under test (CUTs), and redesign these OLTFT structures according to different candidate implement methods. The hardware complexity and fault response rate of these structures are analyzed by using Xilinx synthesis analysis and gate level fault injection simulation. Experimental results show that different OLTFT structures are needed to be designed for different types of CUTs in order to meet the requirements of low cost and high reliability. Finally, the IP core testing methods are analyzed, and some IP soft cores with online-testing and fault-tolerant ability are developed. The conclusions of this paper can be used as guidelines and references for constructing VLSI OLTFT circuits.