US Patent 7586211 Cost optimized redundant power supply with dual AC inputs

A cost optimized redundant power supply consists of a plurality of power units (PUs) wherein each PU has two AC front ends. Each of the two AC front ends receive power from separate AC power sources, and each produce an isolated DC output. The isolated DC outputs from the two AC front ends are coupled to an input of one DC back end, e.g., DC-to-DC converter. Optimally, each of the AC front ends may have a power capacity of TRP/(N+1) and the DC back end may have a power capacity of TRP/N, where TRP=Total Redundant Power or the maximum system power required for operation and N is the number of PUs of the power supply.