In certain embodiments, an apparatus includes an inductor having first and second terminals. The first terminal is configured to be coupled to a power source. The apparatus includes a pair of serially-coupled transistors coupled to the second terminal of the inductor. A transistor intermediate node is positioned between the pair of serially-coupled transistors. The apparatus includes a pair of serially-coupled diodes coupled to the second terminal of the inductor. A diode intermediate node is positioned between the pair of serially-coupled diodes. The apparatus includes a first capacitor coupled in parallel with the serially-coupled transistors and the serially-coupled diodes. The apparatus 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 and is in parallel with a transistor of the pair of serially coupled transistors and with a diode of the pair of serially-coupled diodes.