Leakage Current Optimization Techniques During Test Based on Don t Care Bits Assignment

It is a well-known fact that test power consumption may exceed that during functional operation. Leakage power dissipation caused by leakage current in Complementary Metal-Oxide-Semiconductor （CMOS） circuits during test has become a significant part of the total power dissipation. Hence, it is important to reduce leakage power to prolong battery life in portable systems which employ periodic self-test, to increase test reliability and to reduce test cost. This paper analyzes leakage current and presents a kind of leakage current simulator based on the transistor stacking effect. Using it, we propose techniques based on don＇t care bits （denoted by Xs） in test vectors to optimize leakage current in integrated circuit （IC） test by genetic algorithm. The techniques identify a set of don＇t care inputs in given test vectors and reassign specified logic values to the X inputs by the genetic algorithm to get minimum leakage vector （MLV）. Experimental results indicate that the techniques can effectually optimize leakage current of combinational circuits and sequential circuits during test while maintaining high fault coverage,

Leakage Current Optimization Techniques During Test Based on Don’t Care Bits Assignment

It is a well-known fact that test power consumption may exceed that during functional operation. Leakage power dissipation caused by leakage current in Complementary Metal-Oxide-Semiconductor (CMOS) circuits during test has become a significant part of the total power dissipation. Hence, it is important to reduce leakage power to prolong battery life in portable systems which employ periodic self-test, to increase test reliability and to reduce test cost. This paper analyzes leakage current and presents a kind of leakage current simulator based on the transistor stacking effect. Using it, we propose techniques based on don't care bits (denoted by Xs) in test vectors to optimize leakage current in integrated circuit (IC) test by genetic algorithm. The techniques identify a set of don't care inputs in given test vectors and reassign specified logic values to the X inputs by the genetic algorithm to get minimum leakage vector (MLV). Experimental results indicate that the techniques can effectually optimize leakage current of combinational circuits and sequential circuits during test while maintaining high fault coverage. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. This work was supported in part by the National Natural Science Foundation of China (NSFC) under Grant Nos. 60576031, 60633060, 60606008, 90607010, the National Grand Fundamental Research 973 Program of China under Grant Nos. 2005CB321604 and 2005CB321605, and the Science Foundation of Hefei University of Technology under Grant Nos. 070501F and 060501F. Y. Han's work is also supported by the fund of Chinese Academy of Sciences due to the President Scholarship.