A Parallel Test Application Method towards Power Reduction

As the serial scan design has been one of the most popular methods in VLSI circuit test, power consumption during test increases significantly because of its inherent shift mode. To solve this problem, this paper proposes a novel test scheme, which makes a few improvements in the traditional scan architecture and adopts a new two-phase approach. First, each clock chain is activated in turn and the vectors for scan cells in the activated chain are applied in parallel within a test clock period. Second, after one pattern has been applied completely, all chains are activated to capture the response altogether. In addition, a compression algorithm is proposed to augment the parallelism of our method. Experimental results on benchmark circuits and industrial modules show that, compared with the traditional serial scan scheme, the proposed approach can reduce average power by 88.98% and peak power by 59.99% at acceptable area and wire length cost.