With the increasing switching frequencies and power densities in modern power converters, magnetic core losses are becoming more essential for efficiency and thermal optimization. Traditionally, the two-winding method suffers from sensitivity to phase error in practical measurements; this is mainly created by the unknown phase shift of a current-sensing resistor. Several methods have been developed to characterize the phase shift of a current shunt resistor; however, the load effects of oscilloscopes are ignored. As a result, the corresponding phase shift can be significantly underestimated. This article proposes an improved method for phase shift extraction of a current shunt to solve the problem. The effectiveness of the shunt characterization method is experimentally verified up to 50 MHz. Benefits from the proposed method, the time-consuming component tuning process is not required for core loss measurement. A measurement verification at 10 MHz shows its validity. Finally, a current shunt implemented with a coaxial resistor array is designed with a phase shift of 0.05° at 10 MHz and a parasitic inductance as low as 42 pH.


Electrical and Computer Engineering

Keywords and Phrases

Coaxial resistor; Core loss; Current-to-voltage impedance; Two-port resistor

International Standard Serial Number (ISSN)

1941-0107; 0885-8993

Document Type

Article - Journal

Document Version

Final Version

File Type





© 2023 Institute of Electrical and Electronics Engineers, All rights reserved.

Publication Date

01 Jul 2022