Patent ID: 7557461

Claim:
A power supply method for supplying power to a plurality of load groups each comprising a plurality of loads, comprising the steps of: connecting the output side of each of at least first and second power supply units, including connecting the first power supply unit to a first load group via a first path and the second power supply unit to a second load group via a second path, respectively; connecting at least one third path to the first path of the first power supply unit so as to connect the second load group to at least one redundant power supply unit; connecting at least one fourth path to the second path of the second power supply unit so as to connect the first load group to the at least one redundant power supply unit; providing back current prevention elements that allow current to flow from the at least one redundant power supply unit to the load groups and prevent the flow of current in a reverse direction, midway along each of the third and fourth paths within the respective first and second power supply units; connecting each of the back current prevention elements within each of the first and second power supply units, wherein the back current prevention element provided within the first power supply unit connects to the second path of the second power supply unit via the fourth path, and the back current prevention element provided within the second power supply unit connects to the first path of the first power supply unit via the third path.