Distributed spectrum in full-bridge step-down converter with hysteresis current control

The Electromagnetic Interference (EMI) profile of DC-DC converters has an important influence on their operation in compatibility with other equipment. The EMI filter is designed for the DC-DC converter to attenuate the conducted EMI. The size of the EMI filter depends on the power of the conducted frequencies. The size of the EMI filter may reduce for EMI spectrum with distributed frequencies. Randomization of switching frequency helps distributing switching frequency and EMI spectrum. However, the quality of the output voltage may reduce. In this paper, switching frequency randomization has been applied to a step-down full-bridge converter. Improvements in EMI spectrum and affects on the quality of the output voltage have been investigated.