Class E amplifier operating from a short circuit to an open circuit

It is shown that a Class E tuned power amplifier can be improved by adding an inductive impedance inverter. This improvement ensures that zero-voltage switching of the transistor can be achieved over a very wide range of the load resistance. In the extreme case, the load resistance may vary from zero to infinity. Therefore, the amplifier is suitable for many applications, such as resonant DC/DC power converters and high-frequency power sources for electric induction or dielectric process heating. The authors present the design procedure and experimental results for a Class E amplifier with an inductive impedance inverter. Experimental waveforms and characteristics measured at 1 MHz with an IRF620 MOSFET are given for an amplifier that can operate under zero-voltage switching conditions for load resistances ranging from a short circuit to an open circuit