An apparatus and associated method are provided involving a converter circuit. The converter circuit includes an inductor including a first terminal configured to be coupled to a power source, and a second terminal. Also included is a pair of serially-coupled transistors coupled to the second terminal of the inductor. The pair of serially-coupled transistors have a transistor intermediate node therebetween. Further included is a pair of serially-coupled diodes coupled to the second terminal of the inductor. The pair of serially-coupled diodes have a diode intermediate node therebetween. A first capacitor is coupled in parallel with the serially-coupled transistors and the serially-coupled diodes. Further, the converter circuit includes a sub-circuit having a second capacitor serially-coupled with an auxiliary transistor. The sub-circuit is coupled between the transistor intermediate node and the diode intermediate node.