Switching Power Source and Lighting Device

A switching power source comprising:

• a first inductor;
• a switching element that supplies a power source voltage to the first inductor and flows a current when being on;
• a current control element that has a first main terminal, a second main terminal, and a control terminal, with the second main terminal connected to the switching element, and detects a current flowing in the switching element;
• a control circuit that turns off the current control element and interrupts the current flowing in the switching element when a voltage between the second main terminal and the first main terminal of the current control element is equal to or higher than a specified value;
• a rectifier element that is series-connected to one of the switching element and the current control element and flows the current of the first inductor when the switching element turns off;
• and
• a second inductor that is magnetically coupled to the first inductor, in which a potential turning on the switching element is induced when the current of the first inductor increases and a potential turning off the switching element is induced when the current of the switching element decreases, and supplies the induced potential to a control terminal of the switching element.