Patent ID: 9225257
Filing Date: 2015-12-29
Classification: H02M,H05B

Abstract:
1. A power supply circuit comprising: a DC power supply; a switching element disposed in a current path extending from an output terminal at a high-potential side of the DC power supply to an output terminal at a low-potential side of the DC power supply, via a load; a transformer including a primary coil disposed in the current path and a secondary coil magnetically coupled with the primary coil; a current detector circuit detecting current flowing through the switching element, and outputting voltage corresponding to the current thus detected; a voltage output circuit outputting, when the switching element is turned on, voltage that is dependent on voltage induced by the secondary coil; and an on-off control circuit turning off the switching element when an absolute value of a difference between the voltage output by the current detector circuit and the voltage output by the voltage output circuit is equal to or greater than a threshold voltage, and turning on the switching element when the absolute value of the difference is smaller than the threshold voltage.