Yogendra K. Chawla

New topology for Class E amplifiers

A Class E RF amplifier, which can operate into any load conditions without need for other additional circuitry to protect transistors, is introduced. This is provided by the new topology, which is called an inductive clamp. Our topology incorporates inductive clamp circuitry to the basic Class E amplifier circuit and it has all the benefits of Class E amplifiers. Additionally, it has inherent self-protection that comes with the inductive clamp circuit. A Class E amplifier with the new topology is designed, simulated and implemented. The experimental results are presented and found to be very close to the simulated results. The amplifier drain efficiency is measured around 88% at the rated power level and it is confirmed that the amplifier protected itself and was stable over entire VSWR and dynamic range within the bandwidth of operational frequency. Class E amplifiers with this topology can be used in applications where the load conditions are dynamic.

Improvement of Class E Amplifier with Inductive Clamp Circuit Topology and Its Applications

A class E amplifier with inductive clamp circuit topology is improved to have stability for all load conditions at any DC supply voltage, Vdc. Based on the new improved topology, the RF Amplifier is designed, simulated and built to be used as a driver for any class of RF amplifier operating within five percent of frequency bandwidth. It is shown that class E amplifiers with inductive clamp circuits using an improved topology give all the benefits of class E amplifiers with inductive clamp circuits and in addition have minimum spurious oscillations and harmonic levels. The improved topology and results that we introduce here can be employed in RF applications where the signal purity over entire VSWR and dynamic range is one of the amplifier requirements such as plasma excitation