A Transient Fault Tolerant Test Pattern Generator for On-line Built-in Self-test

Reliable built-in self-test (Reliable BIST) is a scheme in which embedded circuits used for self-testing circuits-under-test (CUTs) are designed to be tolerant of their faults. Reliable BIST is especially important for highly reliable on-line testing for real-time system; reliable BIST is required to recover itself from transient errors of its embedded BIST circuits. In this paper, we propose a transient fault tolerant test pattern generator (TPG) for a reliable BIST scheme. The proposed TPG, called EC-TPG, can correct (or mask) errors that occur on itself during testing CUTs, so that it can enhance its test-reliability, which is the probability that the TPG can generate correct (expected) test patterns. We analyze the test-reliability of EC-TPG in order to show that EC-TPG has high test-reliability. Furthermore we demonstrate that, in on-line BIST for real-time systems, EC-TPG can achieve higher test-reliability compared with a test re-execution scheme with error detection through some case studies.