Patent ID: 6418038
Filing Date: 2002-07-09
Classification: H02M,Y02B

Abstract:
A DCâ€”DC converter comprising:switching means having a pair of switching devices connected in series to form a bridge; a converter transformer having a primary coil and a secondary coil which are wound with a predetermined turns ratio for transferring to the secondary coil the switching output provided for the primary coil by the switching operation of said switching means; series resonant means having a capacitor, an inductor, and the primary coil serving as an inductor which are connected in series to a node between the pair of switching devices, said series resonant means being resonated at a first resonant frequency; parallel resonant means at least having an equivalent capacitance in the primary equivalent to the interwinding capacitance of the secondary coil, and the inductance of the primary coil, said parallel resonant means being resonated at a second resonant frequency higher than the first resonant frequency; voltage supply means connected to the secondary coil serving as a source for supplying an output voltage to a load; and switching control means for varying the switching frequency of said switching means according to variations in the voltage output from said voltage supply means.