ABSTRACT
Classes A, AB, and B amplifiers have been used for linear applications where amplitude modulation (AM), single-sideband (SSB) modulation, and quadrature amplitude modulation (QAM) might be required. In switch-mode amplifiers such as Classes D, DE, E, and F, the active device is intentionally driven into saturation region, and it is operated as a switch rather than a current source. Class D amplifiers have two-pole switching operation of transistors either in voltage-mode (VM) configuration that uses series resonator or current-mode (CM) configuration that uses parallel resonator circuit. This chapter discusses the conventional method to design Class E amplifiers for suboptimum and optimum cases. The circuit variables and parameters of interest include the current and the voltage profile of the power switch, the range and linearity of control achievable with different control methods, and power losses due to any hard-switching of the shunt capacitor voltage.
