A Scan Chain Adjustment Technology for Test Power Reduction

Recently test power dissipation has become a more and more challenging issue. This paper proposes a technique to solve this problem through scan chain adjustment to eliminate unnecessary transitions in scan chains. An extended WTM (EWTM) metric is proposed to estimate dynamic power dissipation in circuit under test caused by transitions in test stimulus and response vectors. And the routing overhead of this methodology can be reduced through scan chain adjustment guided with our distance of EWTM (DEWTM) metric. Experimental results on ISCAS´89 benchmarks circuits show that the proposed approach can reduce average power dissipation during scan test by 72.2% on average, with negligible routing overhead