Current sense resistor (CSR) is widely used due to cost and integration considerations in industrial applications. However, when CSRs are used to sense transient currents caused by power device ...switching, especially fast-switching silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors ( mosfet s) with high di/dt , even a tiny parasitic inductance in CSRs bring a significant impact on its sensing performance. This article proposes a low-cost well-performance and easy-to-design current sensing circuit that uses the CSRs and an LR compensation network (LRCN) to compensate for the effect of parasitic inductance on transient current sensing. In order to support the parameter selection of the LR network, the effects of parameters such as parasitic capacitance, parasitic inductance, and loads on the performance of the proposed current sensing circuit are analyzed in detail. Meanwhile, a parasitic inductance measurement method that only needs passive probes is proposed to measure and calculate the parasitic inductance of CSRs. This circuit can not only sense the transient current on the printed circuit board level but also observe the transient current on the oscilloscope through a coaxial cable connection. Finally, experimental studies under an inductive load double pulse test setup with SiC mosfet s are carried out to verify the validity and feasibility of the proposed transient current sensing circuit. Only a high self-resonant frequency inductor and a surface mounted device resistor are needed to form the LR network to fully compensate the effect of parasitic inductance on CSRs.
In order to improve efficiency and reduce circuit size the switching speeds of semiconductor power devices are being reduced. This is being achieved by the use of wide band-gap semiconductor devices. ...Traditional current measurement techniques are unable to accurately measure these new high speed switching edges, due to a lack of bandwidth and high insertion inductance. In this paper a 1.6 GHz bandwidth, scalable current, SMD shunt based current probe is developed for switching and steady state current measurements in wide band-gap power devices. By designing this shunt with an extremely low insertion inductance of less than 10 pH it is ensured that the measurement circuit has negligible impact on switching device operation.
