Resonance power supply circuit

A resonance power supply circuit comprising:

• a transformer including a primary winding wire and a secondary winding wire including at least a first winding wire and a second winding wire;
• a first switching element and a second switching element that apply a rectangular wave voltage to one end of the primary winding wire;
• a resonance capacitor coupled to another end of the primary winding wire;
• a controller that alternately turns on and off the first switching element and the second switching element to cause the primary winding wire and the resonance capacitor to resonate with each other;
• a first output circuit including a first rectification element and a second rectification element that extract a first alternating-current voltage induced in the secondary winding wire, a first capacitor that smoothens the extracted first alternating-current voltage, an output capacitor that outputs an output voltage, and a backflow prevention rectification element that suppresses a current flowing from the output capacitor into the first capacitor;
• a second output circuit including a third rectification element and a fourth rectification element that extract a second alternating-current voltage induced in the secondary winding wire, a second capacitor that smoothens the extracted second alternating-current voltage, the output capacitor, and a third switching element provided between the second capacitor and the output capacitor;
• and
• a feedback circuit that feeds back voltage information indicating a first voltage of the first capacitor to the controller.