Improving reliability by modifying system configuration

This paper investigates how to improve system reliability by modifying the configuration of its components to realize a robust design. The methodology is applied on the voltage regulator of an electronic circuit with a +5volts regulated power supply. The effect of three different design modifications on the overall system reliability has been investigated, series redundancy, parallel redundancy and parallel-series redundancy. A single factor linear regression with median rank model is used to evaluate the reliability of the three suggested designs. The inverse power law model is used to characterize the relationship between system lifetime (L) and stress (voltage) level (V). Parallel-series design showed the best results regarding system reliability. The average Time-to-Failure at 25 volts stress level for the parallel-series design was found to be 3.5 times that of the initial design, 2.5 times that of the series design and 2.17 times that of the parallel design.