Designs for three new switch-mode power supplies developed by Sanken Electric Co. incorporate a user-configurability feature to prevent customers from having to replace an entire set of supplies. The C, HWB, and SWF series, available from Allegro Microsystems, will find homes in the telecommunications and medical markets. The C series enables end-of-line selection of multiple output voltages to match alternative application circuit requirements while using the same power-supply base unit. The dc voltage-output modules are slot-mounted inside the base units to provide various combinations of single, dual, or parallel output voltages. Thanks to soft-switched, multi-resonant zero-cross (SMZ) type resonant-mode circuits, the HWB series can significantly reduce noise in the converter unit—its ultra-low noise is reminiscent of a dropper power supply. These supplies employ a proprietary resonant-mode hybrid IC and transformer. The compact SWF series offers peak-power capability that supports twice the rated output, suiting them for motorized applications. Current resonant circuitry lowers noise and boost efficiency.