In a described example, an apparatus includes a first switch coupled between a terminal for receiving an input voltage and a top plate node, and having a first control terminal; a second switch coupled between the top plate node and a switching node, and having a second control terminal; a third switch coupled between the switching node and a bottom plate node and having a third control terminal; a fourth switch coupled between the bottom plate node and a ground terminal, and having a fourth control terminal; a flying capacitor coupled between the top plate node and the bottom plate node; a fifth switch coupled between the top plate node and an auxiliary node; a sixth switch coupled between the auxiliary node and the bottom plate node; and an auxiliary capacitor coupled between the auxiliary control terminal and a ground terminal.