Experimental Investigation on Electromagnetic Interference (EMI) in Digitally Controlled Flyback Power Supply for LED Lighting Applications

This paper presents an experimental study on electromagnetic interference (EMI) behavior in a digitally controlled flyback power supply designed for LED lighting applications. The power supply utilizes the Infineon XDPL8105 controller, offering advanced digital regulation features, including programmable output parameters, power factor correction (PFC) and EMI mitigation techniques such as spread spectrum modulation and burst mode operation. The impact of varying the values of EMI filter capacitors was investigated, with fixed output current and voltage. The results demonstrate a significant influence of capacitor values on conducted EMI, with optimal performance observed at 100 nF. Increased capacitance (150 nF) led to resonance effects and EMI levels exceeding regulatory thresholds in the 20-25 MHz band. These findings highlight the importance of precise filter design in achieving EMI compliance.