Control circuit of light-emitting element

A control circuit of a light-emitting element, comprising:

• a rectifying unit which full-wave rectifies an alternating current power supply;
• a switching element;
• a feedback voltage generating unit comprising a transformer having a first winding which generates a magnetic field using a current controlled by switching of the switching element, a second winding which is magnetically coupled to the first winding and which generates a current flowing to the light-emitting element, and a third winding which is magnetically coupled to the first winding and which generates a feedback voltage;
• a reference voltage generating unit which divides a voltage rectified by the rectifying unit and generates a reference voltage;
• a comparator which compares a comparative voltage corresponding to a current flowing to the first winding and the reference voltage and outputs a control signal which controls the switching of the switching element according to a comparison result;
• and
• an averaging capacitor which averages a voltage derived by superposing the voltage rectified by the rectifying unit and the feedback voltage, wherein
• a voltage averaged by the averaging capacitor is applied to the first winding, so that light is emitted from the light-emitting element.