Patent ID: 7504811

Claim:
A boost DC/DC converter including a low-voltage-side port and high-voltage-side port, the boost DC/DC converter comprising: an inductor connected at one end to a positive-pole terminal of the low-voltage-side port; a transformer including a primary winding and a secondary winding interconnected in an oppositely-wound configuration, a common terminal of the primary winding and the secondary winding being connected to another end of the inductor; first switching means for controlling an energizing current of the primary winding which flows to a common reference terminal; second switching means for controlling an energizing current of the secondary winding which flows to the common reference terminal; a first diode, connected between another terminal of the primary winding of the transformer and a positive-pole terminal of the high-voltage-side port, for directing a current from the primary winding to the positive-pole terminal of the high-voltage-side port; and a second diode, connected between another terminal of the secondary winding and the positive terminal of the high-voltage-side port, for directing a current from the secondary winding to the positive-pole terminal of the high-voltage-side port, wherein the inductor connected between the positive-pole terminal of the low-voltage-side port and the common terminal of the primary and secondary windings mainly performs a waveform relaxation/variation function on an input current to enlarge a voltage boosting ration variation range which is determined by a sum of an induced voltage based on the inductor and induced voltages produced by the primary and secondary of the transformer, and wherein the transformer is configured as a magnetic-field cancellation type transformer in which the primary winding and the secondary winding are interconnected magnetically via a single core such that an exciting current flowing in one of the primary winding and the secondary winding and an excited current simultaneously flowing in the other one of the primary winding and the secondary winding cancel the magnetization of the core, the winding ratio between the primary winding and the secondary winding being 1:1.