A power system provides power from a power source to a load via a distribution bus, and includes a DC-DC converter coupled in parallel with a network of switching elements coupled between an output terminal of the power source and the distribution bus. A controller is configured to selectively activate or deactivate the DC-DC converter and each of the switching elements to enable the power source to power the load via the distribution bus. The switching elements may be transistors, and the diodes may be parasitic body diodes of the transistors. The power source may be a battery, such as a rechargeable battery. An output voltage level from the battery may be regulated by the controller as a function of operation of the DC-DC converter and a number of the activated or deactivated transistors.