A power converter includes a power conversion circuit switchably coupled to a first power input and a second power input. The power conversion circuit is operable to generate positive and negative DC output voltages and is configured such that, in a backup mode of operation, the negative DC output voltage is generated using backup power through a first current path of the power conversion circuit that includes a first diode coupled between the second power input and a second DC bus, and, in a line mode of operation, the negative DC output voltage is generated using AC input power through a second current path of the power conversion circuit that bypasses the first diode and includes a second diode coupled between the first power input and the second DC bus.