A Power Efficient BIST TPG Method on Don’t Care Bit Based 2-D Adjusting and Hamming Distance Based 2-D Reordering

Abstract

A power efficient BIST TPG method is proposed to reduce test power dissipation during scan testing. Before the test patterns are injected into scan chain, the test set adopts a series of preprocessed strategies including don't care bit based 2-D adjusting, Hamming Distance based 2-D reordering and test cube matrix based two transpose, all steps will be orderly executed in interspersed way. The six largest ISCAS'89 benchmark circuits verify the proposed method. Experimental results show that the switching activities are effectively reduced when the test set is loaded for on-chip scan testing. ASDFR with MT-filling scheme ensures high compression ratio, the scan-in test power dissipation is further decreased by don't care bit based 2-D adjusting and Hamming Distance 2-D reordering. In addition, the BIST TPG method with less test application time and smaller algorithm complexity can be widely applied to actual chip design without adding extra decoder area overhead.