Switching Power Source and Lighting Device

摘要

A switching power source includes first and second inductors, a switching element, current control element, rectifier element, and control circuit. The switching element supplies a power source voltage to the first inductor. The current control element detects a current flowing in the switching element and has first and second main terminals, and a control terminal, with the second main terminal connected to the switching element. The control circuit 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. The rectifier circuit is series-connected to one of the switching element and the current control element. The second inductor is magnetically coupled to the first inductor, in which a potential turning on and off the switching element can be induced.

主权项

1. 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.