Abstract—Recently, many low-power LED (Light Emitting Diode) lighting fixtures that can contribute to a low-carbon society have been installed in clinical settings. However, since Alternating Current (AC) voltage cannot be used directly for LED devices, Direct Current (DC) voltage must be applied LED devices. For this reason, it is necessary for the LED equipment to install an ACDC power converter. A buck converter as an ACDC power converter is applied to the LED equipment, but Electromagnetic Interference (EMI) radiated from it has a strong influence on the wireless communication of a medical place. In particular, EMI radiated emission to medical telemeter systems using wireless communication becomes a significant problem of biomedical signal discontinuations. To investigate the EMI radiated strength, it must be measured using CISPR11 medical equipment international standard (International Special Committee on Radio Interference) on Limits and methods of measurement. This paper is focused on the LED drive DC power converter EMI radiated emission. The CISPR11 measurement EMI disturbance characteristics when a buck type current control DCDC buck converter circuit is used for the lighting of an LED device are shown. It is reported experimental results of EMI radiated emission characteristics improvement by changing the input and output circuit constants of the proposed circuit. Moreover, it is shown that can reduce to the floor noise level (background noise) when an output capacitor is inserted without an input filter. 

Index Terms—medical LED, DCDC buck converter, EMI radiated emission, input filter, output capacitor

Cite: Kiyotaka Fuji and Yasuhiko Neba, "Electromagnetic Interference Characteristics and Reduction Using CISPR11 for a Medical Light Emitting Diode Drive DCDC Buck Converter," International Journal of Electronics and Electrical Engineering, Vol. 9, No. 3, pp. 78-82, September 2021. doi: 10.18178/ijeee.9.3.78-82