Patent ID: 7057906

Claim:
An insulating switching DC/DC converter, in which a DC voltage source is connected to a primary side of an insulating transformer, voltage is transformed by alternately turning on/off a first switching device and a second switching device so as not to simultaneously turn on the switching devices, the first and second switching devices being connected to the primary side, and an output of DC voltage is obtained via a secondary rectifier circuit of the insulating transformer, comprising: an input choke coil, an output choke coil, and the insulating transformer, wherein the input choke coil, a primary coil of the insulating transformer, a secondary coil of the insulating transformer, and the output choke coil are wound around a common core, and the coils are arranged in directions of canceling DC fluxes generated by windings of the coils, and wherein a primary circuit is formed on the primary side of the insulating transformer, the primary circuit including the first switching device connected in series with the primary coil, the input choke coil connected across terminals of the primary coil, and a series circuit of a clamp capacitor and the second switching device which are connected across the terminals of the primary coil, and a secondary circuit is formed on a secondary side of the insulating transformer, the secondary circuit including a first rectifying device and a second rectifying device which are connected to the secondary coil, the output choke coil connected to the first and second rectifying devices, and an output smoothing capacitor connected to the output choke coil.