Recently, power dissipation in full-scan testing has brought a great challenge for test engineers. In addition to shift power reduction, excessive switching activity during capture operation may lead to circuit malfunction and yield loss. In this paper, a new algorithm is proposed with using clock gating technique on a part of the scan cells to prevent the internal circuit from unnecessary transitions. These scan cells are divided into several exclusive scan groups. For each test vector, only a portion of the scan groups are activated to store the test response per capture cycle. The proposed method can reduce the capture power dissipation without any influence on fault coverage or testing time. Experimental results for ISCAS'89 benchmark circuits show that the capture power reduction in test sequence can up to 55%.
Tamkang Journal of Science and Engineering=淡江理工學刊 14(1), pp.39-48