Influence of junction capacitance of switching devices on Class E rectifier

A Class E low dv/dt rectifier, which is a counterpart of a class E zero-voltage-switching (ZVS) inverter, is suitable for high-frequency and high-efficiency rectification with low noise. In the Class E low dv/dt rectifier, the junction capacitance of the diode is included in the shunt capacitor, which has been regarded as a constant capacitance. However, some kinds of Class E rectifiers have a MOSFET instead of a diode to regulate the output power or to reduce the power dissipation. The junction capacitance of a MOSFET is generally larger than the junction capacitance of a diode. Therefore, depending on the value of the shunt capacitor, the nonlinear behavior of the junction capacitance cannot be ignored. In this paper, the influence of the nonlinear behavior of the junction capacitance on the switch voltage waveform of the Class E low dv/dt rectifier with MOSFET is verified and discussed based on the results with numerical analysis and circuit experiments.