| Abstract |
PCB coil, when placed near a current carrying trace, senses the rate of change of current by virtue of its flux linkages through the coil. Thereafter, the coil output is integrated to obtain the sensor output which is proportional to the trace current. Proximity of the PCB coil to external current carrying conductors can make the coil susceptible to undesired flux linkages which can interfere with the operation of the sensor. Furthermore, presence of a switching node near the coil, with high dv/dt, can influence the sensor output through parasitic coupling with the coil. This paper investigates the influence of external magnetic fields as well as on-board dv/dt on the performance of PCB coil based current sensors. Based on theoretical analysis followed by experimental investigations on two PCB coil prototypes on a half-bridge board, design guidelines for enhancing noise immunity of PCB coils are presented. |
