Class E DC/DC Converters with an Inductive Impedance Inverter

The analysis, design equations, and experimental verification are presented for a Class E dc/dc switching-mode high-efficiency resonant dc/dc power converter with a transformer center-tapped rectifier. The analysis is performed at a constant current through the dc-feed choke and using the high-Q(1) assumption (Q(1) >= 5). The converter may operate under safe conditions for load resistances ranging from a full load to an open circuit. This feature has been accomplished by using an inductive impedance inverter. The results of the analysis are then generalized for the entire family of Class E dc/dc converters. Experimental results show good agreement with the theoretical predictions. The measured total efficiency was 89 percent at 1 MHz with 15 W output power. A narrow-band FM regulation (Delta f/f = 12 percent) of the dc output voltage was achieved as the load was varied from a minimum resistance (full load) to an open circuit.