Abstract: A direct current to direct current (DC/DC) converter includes a resonant converter stage, a buck stage, and a processor apparatus. The resonant converter stage includes a bridge circuit. The buck stage is configured to output an output voltage and an output current, is electrically connected in series with the resonant converter stage, and includes a buck switch. The processor apparatus is configured to sense the output voltage and the output current, and, based on the sensed output voltage and the sensed output current, to perform one of: (a) fixing a switching frequency of the bridge circuit to a predetermined maximum switching frequency and controlling the output voltage by controlling a duty cycle of the buck switch, and (b) fixing the duty cycle of the buck switch to a predetermined duty cycle and controlling the output voltage by controlling the switching frequency of the bridge circuit.

Abstract: A DC/DC converter includes a transformer having a primary winding electrically connected to a resonant network and a secondary winding having a plurality of taps including a common tap, a first tap, and a second tap. The DC/DC converter further includes a plurality of rectifier circuits including a first rectifier circuit electrically connected to the common tap, a second rectifier circuit electrically connected to the first tap, and a third rectifier circuit electrically connectable to the second tap. The DC/DC converter also includes a switch electrically connected between the second tap and the third rectifier circuit. The switch is operable to electrically connect and disconnect the third rectifier circuit from the second tap.

Abstract: A spool (20) made of thick metal sheet for a fine metal wire comprises a core (22), and two flanges (24), coupled to the core (12). The core (22) comprises two concentric drums, an inner drum (26) with inner diameter d, and an outer drum (28) with outer diameter D. The spool changes the load distribution of side pressure on the flanges and further improves the structural rigidity of the spool to against deformation.