Encoding Test Pattern of System-on-Chip (SOC) Using Annular Scan Chain

With the improvement of System-on-Chip integration, chip requires an increasingly large amount test data. To solve contradiction between storage capacity and bandwidth automatic equipment (ATE), a new method data compression/decompression is proposed based on annular scan chain. Corresponding fault bits different patterns are incompatible, moving in chain, makes all corresponding be compatible or backward-compatible, so adjacent form relation that indirectly achieves purpose compression by encoding these backward-compatible patterns. According to experimental results, average ratio increases %6.94 % 15.1 compared with other schemes, relative decompression architecture simple. In pattern moves clockwise minimal bits, generating subsequent quickly, it advantageous reduce application time single IP core.