Analysis of class-DE PA using MOSFET devices with non-equally grading coefficient
Ali Lotfi, Akihiko Katsuki, Fujio Kurokawa, Hiroo Sekiya, Marian K. Kazimierczuk, and Frede Blaabjerg
IEEE Transactions on Circuits and Systems I: Regular Papers, vol.66, no.7, pp.2794-2802, Mar., 2019. [pdf document]

<Abstract>

The design and analysis of a new operation-mode of the class-DE power amplifier (PA) using two MOSFETs with the non-equal grading coefficient is introduced. The PA uses the optimum shunt capacitance for each MOSFET to achieve zero voltage switching (ZVS) condition and wide range for the loadresistance point of view. As compared with the conventional classDE PA, this configuration has low value of the series inductance that is reduced the power dissipation. A design procedure with intuitive curves is obtained that are implemented using a different grading coefficient for two MOSFETs. These criteria prepared an effective approach regardless of the fixed shunt capacitance for achieving ZVS condition. The desired operation of the classDE PA is guaranteed by converging of design parameters and required output power. Moreover, non-similar switches provide reduced switch power dissipations and the number of the driving circuit PA. The simulation and experiment results are approved by implementing the outlined theoretical relationships for a fabricated class-DE PA at 4-MHz switching frequency and obtained 12.1-W output power.