Current Sensing
Fast-switching SiC converters need current sensors that are compact, fit close to the power devices and respond quickly enough to capture switching transients. Two PCB-integrated sensors developed in this work balance bandwidth, sensitivity, isolation and manufacturability in different ways.
PCB Rogowski Coil (PCB-RC)
An air-cored PCB winding senses the rate of change of current, and an on-board integrator recovers the current signal. With no core to saturate, it suits large, fast transients. A review of the coil’s development and of PCB winding trade-offs led to five coil designs with saw and fishbone patterns, circular and square outlines, with and without a return line and with a cutout, each with its own signal-conditioning circuit.
Read the PCB Rogowski coil project
Embedded-Core PCB Current Transformer (PCB-CT)
A ferrite core embedded between PCB layers, with a secondary winding formed by traces and vias, delivers a scaled secondary current without an integrator. The work covered the winding layout and a design workbook that sizes bandwidth, saturation and trace current, with repeatable manufacture as a design aim.