Embodiments of the present invention provide a system that supplies power in a computer system. The system includes a power adapter coupled to a source of electrical power and a set of a set of power consumers coupled to a power bus in the computer system. A full-power mechanism coupled between the power adapter and the power bus supplies power for the power consumers while the computer system is operating in a full-power mode. A low-power mechanism coupled between the power adapter and the power bus in parallel with the power mechanism supplies power for the power consumers while the computer system is in operating in a low-power mode.