Abstract: An improved fly forward converter including a capacitor connected across the collector and emitter of a switching transistor to form a parallel resonant circuit with the converter's transformer primary inductance, a diode across the switching transistor collector capacitor to conduct excess energy from the resonant circuit and coupling diodes in the converter's output circuit for coupling the energy in both the forward and flyback phases through an output inductor serially connected between the transformer secondary and the output capacitor. The converter includes a shunt capacitor with circuit values adjusted so that resonant action continues until the switching transistor voltage falls to zero for achieving "zero voltage switching". Zero voltage switching is achieved by varying the duration of the active cycle while the reset cycle duration is fixed and determined by resonant component value.

Abstract: A circuit and method for converting three-phase .DELTA. AC to a higher voltage DC output. The method utilizes first, second and third rectifying circuits and a storage circuit to provide DC. The circuit herein does not require an independent DC power source, nor a neutral AC connection, as used for conventional Y connected power systems. The circuit herein also provides a uniform loading to all three phases of the AC input. A preferred embodiment is provided herein comprised of twelve diodes and three capacitors, wherein the diodes rectify the current, and the capacitors store charge.

Abstract: An improved resonant forward dc-to-dc converter circuit includes control circuitry for achieving an optimal power cycle in which the transistor is either supplying current to the load or recovering in a sinusoidal manner, for limiting power loss by controlling the switch turn on time to the time when the switch collector voltage at recovery is at a mimimum, for maintaining an approximately constant turn off time and for providing pulse by pulse current mode control for high loop stability and superior transient response.

Abstract: A DC to AC converter has a linear output amplifier for simplification and for reducing distortion and output noise. A DC to DC converter or converters provides outputs regulated to have small predetermined voltage differentials to the supply output. This insures a high overall efficiency. A rectifier-filter added to the input converts the unit to an AC to AC power supply.