Novel Current Sensor Based on Parasitic Inductance With Adaptive Compensation for Parasitic Resistance

In this article, a novel current sensor that leverages the existing parasitic inductance within the power loop of converters is proposed to accurately measure the current of power devices, featuring high density, high bandwidth, low cost, and nonintrusiveness. The primary addressed challenge is the impact of parasitic resistance of the trace used for sensing, which affects the operation of the proposed sensor. To mitigate this issue, an integrator circuit with programmable compensation for parasitic resistance is proposed to effectively eliminate the influence of parasitic resistance on the sensor output. Furthermore, to tackle the variability of temperature-sensitive parasitic resistance, an innovative online adaptive method is proposed. This method dynamically adjusts the compensation for parasitic resistance, ensuring that its influence is automatically canceled, even when the exact resistance value is unknown in advance. The proposed current sensor not only overcomes the limitations associated with parasitic resistance but also offers a versatile and robust solution for accurate current measurements in power circuits. This article is accompanied by one video demonstrating the dynamic process of adaptive compensation for parasitic resistance.