Abstract: The present invention employs a resonant inductor, a resonant capacitor and a hybrid transformer using a Hybrid-switching method with three switches which results in two distinct switched-networks: one for ON-time interval and another for OFF-time interval. Resonant inductor is placed in series with the hybrid transformer primary to insure the continuity of primary and secondary currents at the switching transitions and thus eliminating completely the potential switching losses at the switching transitions. In the best use of the invention the resonant inductor is replaced by use of the inherent leakage inductance of the transformer and for the first time eliminate the switching losses always associated with the transformer leakage inductance of all other switching converters. The output voltage is controlled by the standard Pulse Width Modulated (PWM) duty ratio control.

Abstract: A number of non-isolated and isolated converter embodiments are disclosed all featuring the three switches and characteristic not present in prior-art converters such as: a) reduced voltage stresses on all three switches resulting in safe operation without a danger of voltage overstress of any of the three switches over the full operating range from duty ratio of 0 to 1.0 and thus resulting in wide input voltage operating. b) operating range with magnetics flux and magnetic size much reduced compared to prior-art converters c) stressless switching eliminates switching losses and reduces stresses which are present in prior-art converters. All three features result in simultaneous increase of efficiency, reduction of size and cost when compared with prior-art converters.

Abstract: A storageless DC-DC converter is provided having simultaneously ultra high efficiency of 99.5% in an ultra compact size leading to 1 kW/inch3 power density, while also providing a regulation over the wide input DC voltage range. In addition to fixed 2 to 1 step-down voltage conversion the continuous output voltage reduction is obtained by use of a new method of the modulation of the freewheeling time of one of the two current rectifiers. This provides a simple regulation of the output voltage via a standard duty ratio control, despite the wide range of the input voltage change and simultaneous wide range of the load current change. An alternative control method customarily used in classical resonant converters to control output voltage by change of the switching frequency with a fixed duty ratio control is also demonstrated.

Abstract: A four-switch step-down storageless DC-DC converter is provided having simultaneously ultra high efficiency of over 99% in an ultra compact size, while also providing a regulation and maintaining fast transient response while in regulation. Because of its storageless feature it is ideal for demanding computer applications, such as VRM (Voltage Regulator Modules), with extremely fast step-load load current change requirements and tight output voltage regulation requiring ultra low output ripple voltages during the transients.

Abstract: Switching Converter with a novel two-loop Integrated magnetic structure integrates transformer and two output inductors and eliminates large circulating current in the transformer secondary side resulting in ultra high efficiency and zero ripple output current as well as zero ripple currents in both output inductors simultaneously. The novel lossless switching method eliminates the primary side switching losses to result in switching converter with highest efficiency, compact size and additional performance advantages, such as ultra low output ripple voltage, low EMI noise and improved reliability with additional benefits when operated with a front-end Power Factor Converter for computer server applications.

Abstract: Unlike buck converter and tapped-inductor buck converters, which use only inductive energy transfer, the present invention employs the capacitive energy transfer in addition to inductive energy transfer. The hybrid transformer performs the double duty simultaneously: transfers the input inductive energy storage to the load through a taped-inductor turns ratio n but also transfers the resonant capacitor discharge current to the load during OFF-time interval amplified by turns ratio m of the hybrid transformer. Despite the presence of the resonant inductor current during the OFF-time interval, the output voltage is neither dependent on resonant component values nor on the load current as in conventional resonant converters but depends on duty ratio D and turns ratio n of the hybrid transformer. Hence a simple regulation of output voltage is achieved using duty ratio control.

Abstract: Switching Converter with a novel two-loop Integrated magnetic structure integrates transformer and two output inductors and eliminates large circulating current in the transformer secondary side resulting in ultra high efficiency and zero ripple output current as well as zero ripple currents in both output inductors simultaneously. The novel lossless switching method eliminates the primary side switching losses to result in switching converter with highest efficiency, compact size and additional performance advantages, such as ultra low output ripple voltage, low EMI noise and improved reliability with additional benefits when operated with a front-end Power Factor Converter for computer server applications.