Power-supply arrangement

A power-supply arrangement comprises a transformer having first and second primaries and first and second secondaries on a common core, the primaries being fed by first and second power-sources, respectively, and the secondaries feeding first and second loads, respectively. The sources drive the primaries through a switch arrangement on a TDM basis, such that (a) when the first source (mains) is healthy, energy from that source is used to charge the magnetic circuit of the transformer, that energy being then transferred to the first load (an S0 bus), while in a separate time-period energy from the second source (a Uk0 bus) is used to charge the magnetic circuit, that energy being then transferred to the second load (Vcc of a transmission interface section), and (b) when the first source drops out, energy from the second source is used to charge the magnetic circuit and thereafter the magnetic circuit is discharged into both first and second loads. The first load (S0) may be reduced in this case. The charging/discharging operations are carried out on a continuous basis.