Current Sensor in PCB Technology

A novel DC/AC current sensor works on the fluxgate principle. The core in the form of a 7/10mm ring made of electrodeposited permalloy is sandwiched into the middle of the printed circuit board (PCB), while the sensor excitation winding is also integrated in the copper layers of the PCB. In order to lower the sensor power consumption, the excitation winding was tuned by a parallel capacitor. The peak-peak/rms ratio of 5.2 was achieved for the excitation frequency of 25 kHz. The open-loop sensor has 100 mA/A sensitivity; the characteristics has linearity error of 10% and hysteresis below 0.1 % in the 1A range.