Fundamental Study of Current Measurement in Planar Conductor with Optical-probe Current Sensor

In this study, we aimed to accurately measure the current passing through a planer conductor with rectangular cross section in electronic circuits such as those of power converters, which feature increasingly high frequencies. Recently, the authors invented an optical-probe current sensor based on the Faraday-effect employing a very small sensor head with low insertion impedance. We investigated a method for measuring the magnetic field on conductor surface using this sensor, and a method for inversely analyzing the current distribution in planer conductors such as surface wiring on printed circuit boards, transistor outline package leads, and busbars. Furthermore, we discuss the inverse analysis method for current distribution using gradient descent based on the measured magnetic field distribution. Finally, we present the transient response of current distribution and total current analyzed by gradient descent.