Enhancements to the Non-Invasive Current Estimation Technique Through Ground Isolation

Techniques for predicting or measuring the dynamic current of a high-performance integrated circuit have proven useful when applied in theory. However, the practical application of such methodologies in the lab is much more challenging. Test equipment imperfections have significant influence on the dynamic and static voltage measurement accuracy and thereby impede accurate prediction of chip load current. This paper empirically addresses the presence of ground loops in the measurement system and demonstrates appropriate isolation techniques to resolve the two-channel oscilloscope voltage measurements necessary for accurate load current calculation. In addition, these findings are correlated with simulations by adding oscilloscope and cabling parasitic inductance and resistance to simulation models, which further demonstrate the importance of ground isolation.