Deterministic built-in self-test using split linear feedback shift register reseeding for low-power testing

A new low-power testing methodology to reduce the excessive power dissipation associated with scan-based designs in the deterministic test pattern generated by linear feedback shift registers (LFSRs) in built-in self-test is proposed. This new method utilises two split LFSRs to reduce the amount of the switching activity. The original test cubes are partitioned into zero-set and one-set cubes according to specified bits in the test cubes, and the split LFSR generates a zero-set or one-set cube in the given test cube. In cases where the current scan shifting value is a do not care bit accounting for the output values of the LFSRs, the last value shifted into the scan chain is repeatedly shifted into the scan chain and no transition is produced. Experimental results for the largest ISCAS´89 benchmark circuits show that the proposed scheme can reduce the switching activity by 50% with little hardware overhead compared with previous schemes.