Design, construction and control of a quasi-resonant SMPS working at 2 MHz

Switching Mode Power Supplies with higher switching frequencies are, in general, smaller in size for the same power rating. Resonant converters have an advantage over PWM-type converters because they use soft switching, reducing losses and increasing the energy efficiency of the power electronic circuit. In this paper, a converter is designed having a switching frequency more than 2 MHz. The power is regulated and varies between 15 and 50 W, at a constant output voltage of 15 V. An LLC-type topology is chosen as resonant tank, in which the parasitic transformer leakage inductance is efficiently employed. An experimental converter was built, handling 50 W at 1.4 MHz. The efficiency is up to 60 % at full load..