Switching power supply device

摘要

In a switching power supply device, a partition portion that includes a slit divides a winding portion of a bobbin. A primary winding of a transformer is wound to a height h1 in a first section, and a secondary winding is wound to a height h2 in a second section. A low side drive winding and a high side drive winding are wound around the primary winding to a height h3 with the high side drive winding being located toward the secondary winding.

主权项

1. A switching power supply device, comprising:
a power supply voltage inputting unit configured to accept input of an input power supply voltage; a direct current voltage outputting unit configured to output a direct current voltage; a transformer including a primary winding and a secondary winding that are wound around a winding portion of a bobbin, a low side drive winding, a high side drive winding, and a core defining a closed magnetic circuit; a capacitor that defines an LC resonant circuit including the primary winding; a series circuit that is connected to the power supply voltage inputting unit and that includes a low side switching element and a high side switching element; and a switching controlling circuit that includes a low side switching controlling unit configured or programmed to control the low side switching element and a high side switching controlling unit configured or programmed to control the high side switching element; wherein the LC resonant circuit includes a leakage inductance of the primary winding or the secondary winding of the transformer; the low side switching element is connected to the primary winding in series and is configured to apply a voltage of the power supply voltage inputting unit to the primary winding upon being turned on; the low side switching controlling unit is configured or programmed to turn on the low side switching element upon detecting a reversal of a polarity of a winding voltage generated in the low side drive winding and turn off the low side switching element at a timing that is based on a feedback signal of a circuit that detects an output voltage; the high side switching controlling unit is configured or programmed to turn on the high side switching element upon detecting a reversal of a polarity of a winding voltage generated in the high side drive winding and turn off the high side switching element in accordance with an on time of the low side switching element; the bobbin includes a partition portion that includes a slit; the partition portion is provided along an outer periphery of the winding portion and divides the winding portion into a first winding area in which the primary winding is wound and a second winding area in which the secondary winding is wound; the primary winding is wound to a first height h1 from the outer periphery of the winding portion; the secondary winding is wound to a second height h2 from the outer periphery of the winding portion; and the low side drive winding and the high side drive winding are wound on the primary winding so as to be next to each other in a winding axis direction with the high side drive winding located toward the secondary winding.