Power supply circuit and illumination apparatus

摘要

According to one embodiment, there is provided a power supply circuit (14) including a power conversion unit (21), a controller (22), and an integrated circuit (23). The power conversion unit (21) converts an AC voltage, supplied through a power supply path (26a), into a different voltage and supplies the converted voltage to a load (12). The controller (22) controls the power conversion unit (21) to perform the voltage conversion. The integrated circuit (23) includes an input terminal (40) that is electrically connected to the power supply path (26a), a current regulator (42) that can switch between a first state in which a part of a current flowing through the power supply path (26a) flows to the input terminal (40) and a second state in which a current flowing to the input terminal (40) is lower than that of the first state, a controller power supply (44) that converts a voltage, supplied through the current regulator (42), into a driving voltage and supplies the driving voltage to the controller (22), a connection terminal (47) for connecting an auxiliary power supply (50) which is used for generating the driving voltage, and a protection circuit (48) that blocks or decreases, when an auxiliary power supply voltage of the auxiliary power supply (50) decreases, a current flowing to the input terminal (40).