Real-Time and Noninvasive Monitoring of Transient Current for Printed Circuit Module Diagnosis

Noninvasive monitoring of transient currents is valuable for the diagnosis of industrial electronics. However, traditional noninvasive current probes fail to provide real-time transient waveform monitoring on printed traces. In this article, an integrated current probe is proposed, with well-designed passive sensing part and active integrator circuit. The integrated current probe offers a typical transfer impedance of 0.1637$\boldsymbol{\Omega}$in a 3-dB bandwidth spanning from 215 kHz to 720 MHz. Square-wave current (up to 50 MHz) and ISO 7637-2 Pulse 3A and 3B are selected to validate the real-time monitoring capability of the probe on the current along printed trace, with the error down to 1.62% compared with direct measurement. Finally, the probe is applied to a practical automotive protection circuit module, showing the successful noninvasive current monitoring with a low error of 2.97% compared with a commercial probe. The proposed probe can be a powerful tool for real-time and noninvasive current diagnosis on printed circuit modules.