To provide a switching power supply device and a lighting device that implement a simple structure of an inductor of the switching power supply device even if employing an auxiliary winding on the inductor.
In an embodiment, the switching power supply device includes: input ends; a DC power supply connected to the input ends; a chopper circuit connected to the DC power supply; and output ends connected to the chopper circuit and connected to a load. The chopper circuit has: a first inductor; a second inductor; a third inductor; a switching element for, when turned on, causing an augmented current to flow from the DC power supply to the first and third inductors; a constant current element connected in series with the switching element; a rectification element for causing a reduced current to flow to the first and third inductors while the switching element is turned off; and a drive circuit for controlling a gate voltage of the switching element to turn it off when the switching element is turned on and the augmented current reaches a saturation state of the constant current element.
KITAMURA NORIYUKI
OTAKE HIROKAZU
TSUJI TOSHIO
