A Self-Tuned Class-E/F3 Power Oscillator

Class-E/F
₃
power amplifier (PA) is a hybrid switching PA that enhances the performance of Class-E PA by reducing its peak switch voltage. The output power and the efficiency of a Class-E/F
₃
PA are sensitive to the values of the load network components. To minimize this issue, we propose a Class-E/F
₃
power oscillator (PO) whose feedback network is composed of a low-Q
RC
circuit. In the proposed circuit, the switching frequency of the PO is defined by the resonance frequencies of the load network, and as such, the PO remains fairly tuned, even if the load network components vary considerably. As a result, the output power and the efficiency of the proposed PO show negligible sensitivities to the changes in the component values. Additionally, we present a design procedure for the proposed PO. To verify the circuit operation and the design procedure, a prototype circuit was designed and implemented. At
${{V}_{\text{DD}}} = \ \text{4.5}{\rm{\ V}}$
, the measured output power, the efficiency, and the switching frequency of the prototype PO are
$\text{1.023}\ \mathrm{W}$
, 93.5%, and
$\text{800}\ \text{kHz},$
respectively. Simulation and measurement results confirm that the output power and the efficiency of the proposed PO have negligible sensitivities to the variations in the component values.