POWER SUPPLY CIRCUIT AND LIGHTING DEVICE

PROBLEM TO BE SOLVED: To provide a power supply circuit and a lighting device that suppress a power loss.SOLUTION: According to an embodiment, the power supply circuit provided includes a power conversion section, a current regulation section, a control section and a control power supply section. The power conversion section converts an AC voltage with a controlled conduction angle supplied via a power supply path to feed a load. The current regulation section has a branch path connected to the power supply path, and switches between a first state in which part of a current through the power supply path flows to the branch path and a second state in which the current flowing to the branch path is lower than in the first state. The control section detects a conduction angle of the AC voltage and controls the switching of the current regulation section in accordance with the conduction angle. The control power supply section is connected to the branch path and converts a supplied voltage to feed the control section. The control section switches the current regulation section to the second state in at least a part of an on interval of the detected conduction angle, and switches the current regulation section to the first state in an off interval of the detected conduction angle.