Patent ID: 7643314
Filing Date: 2010-01-05
Classification: H02M,Y02B

Abstract:
1. A resonant switching power source device, comprising first and second switching elements connected in series to a DC power source; a resonant series circuit which comprises a current resonance capacitor, and a primary winding and an inductance of a transformer connected in parallel to said first or second switching element; and a rectifying smoother connected to a secondary winding of said transformer; said transformer comprising: a magnetic core of first and second core halves coupled together in opposed relation to each other to form at least one closed magnetic circuit for supporting said primary and secondary windings wound around said first and second core halves; and a gap defined between end surfaces of said first and second core halves by spaced relation of said end surfaces to also form a reduced section area by contacting the end surfaces; the on-off operation of said first and second switching elements causing a resonance current to flow through said resonance capacitor, primary winding and inductance of the transformer, and first or second switching element to produce a DC output from said secondary winding of the transformer through said rectifying smoother; wherein said reduced section area comes to magnetic saturation to reduce an excitation inductance of said transformer when a large amount of electric current flows through said resonant series circuit; and the excitation inductance of the transformer is increased when a small amount of electric current flows through said resonant series circuit.