The effect of ferrite bead on conducted emission in an automotive led driver module with dc-dc converters

Abstract

Commonly, ferrite beads are used for reducing high-frequency emissions generated by electronic modules. Even though the high impedance attribute of ferrite beads at high frequencies is useful in reducing radiated emissions (RE), their inductive character in the low-frequency region necessitates consideration of conducted emissions (CE). In this research, the behavior of the ferrite bead used for reducing the emissions generated by the LED driver module of the front fog lamp of a passenger vehicle has been experimentally investigated in the low-frequency region. For this purpose, the CE test, which is one of the most crucial electromagnetic compatibility (EMC) tests in the automotive industry, has been performed. Moreover, two different designs of the concerned PCBs have been research and developed. Then, CE tests have been carried out for both designs in a semi-anechoic chamber. Thus, the highest CE values for the model including ferrite bead have been obtained as 82.49 dB mu V for 210 kHz but for the model including 0R (zero-ohm) have been acquired as 78.81 dB mu V for 182 kHz, respectively. Using empirical results obtained in this research, effect of ferrite bead in the 150 kHz-108 MHz frequency range has been examined and interpreted with the help of corresponding simulations.