Extracting the Dynamic Current of a Power Delivery Network

Measuring dynamic current at a multi-pin load, such as an FPGA, creates significant challenges. There is no practical way of installing current loop probes, or sense resistors in every power and ground pin pair that connect to the load. This paper demonstrates a practical approach for extracting the dynamic current going into a multipin load component on a PCB. The method uses the creation of an accurate EM model with components of the distributed power delivery network (PDN) in combination with measured voltages at the VRM input to the PDN and at the load on the output of the PDN. This method enables power integrity engineers to see the hidden impact of dynamic current on the power rail noise.