Design of accumulator Based 3-Weight Pattern Generation using LP-LSFR

The objective of the BIST is to reduce power dissipation without affecting the fault coverage. Weighted pseudorandom built-in self test (BIST) schemes have been utilized in order to drive down the number of vectors to achieve complete fault coverage in BIST applications. Weighted sets comprising three weights, namely 0, 1, and 0.5 have been successfully utilized so far for test pattern generation, since they result in both low testing time and low consumed power. In this approach, the single input change patterns generated by a counter and a gray code generator are Exclusive–ORed with the seed generated by the low power linear feedback shift register [LP-LFSR]. Since accumulators are commonly found in current VLSI chips, this scheme can be efficiently utilized to drive down the hardware of BIST pattern generation, as well. From the implementation results, it is verified that the testing power for the proposed method is reduced by a significant percentage.