An apparatus comprising an ac/dc power supply for providing power to power consumers in an internet data center or to a stand-alone server includes power-handling circuitry and a passive heat-dissipation system that passively dissipates heat generated by the power-handling circuitry. The passive heat-dissipation system comprises a housing that encloses that power-handling circuitry and a thermal network that provides thermal communication between the power-handling circuitry and faces of the housing.