Patent ID: 6778412
Filing Date: 2004-08-17
Classification: H02M,Y02B

Abstract:
A DC-DC converter for converting an input voltage at an input-output conversion ratio and for outputting the converted voltage to a load, comprising:a switching element, the input voltage being converted in response to switching operation of the switching element, and the input-output conversion ratio being determined by the switching operation of the switching element; a choke coil, through which converted voltage is applied to the load; a reverse current detector for detecting a reverse current flowing from an output side to an input side of the DC-DC converter; and a reverse current suppressor suppressing the amount of reverse current flowing when a reverse current is detected; wherein the choke coil has a function of increasing the inductance when the current is within a current operating range that is less than or equal to a predetermined value and decreasing the inductance when the current is in a current operating range that exceeds the predetermined value; and the choke coil includes a core which easily becomes locally magnetically saturated, and the choke coil has swinging characteristics in which the inductance decreases when the amount of current flowing through the choke coil becomes a predetermined value or greater, thus causing local magnetic saturation in the core.