Ea. Vendrusculo et Ja. Pomilio, SOFT COMMUTATION IN CAPACITIVE IDLING CONVERTERS, IEEE transactions on industrial electronics, 45(3), 1998, pp. 521-522
The capacitive idling converters derived from the Cuk, SEPIC, Zeta, an
d Flyback topologies allow soft commutation of power switches without
the need for additional circuitry, making it possible to increase the
switching frequency while maintaining high efficiency.