In certain embodiments, a compound power converter passes the majority of power from input to output through only a single stage of power conversion. At least one embodiment includes a main converter with an auxiliary output. The auxiliary output energizes an energy storage element that provides input power for a supplemental converter capable of supplying the main output. The supplemental converter improves regulation and can provide holdover power for Power Factor Correction (PFC) or Uninterruptible Power Supply (UPS) operation. In certain embodiments, the power converter has at least one multi-functional inductor that supports both main regulation and supplemental regulation in a time-multiplexed manner such that, during main regulation, input energy is transferred from the input node to the output node via the multi-functional inductor, and, during supplemental regulation, the stored energy is transferred from the at least one energy storage element to the output node via the multi-functional inductor.