Power supply for illumination and luminaire

摘要

A power supply for illumination includes a detection circuit and a control circuit. The detection circuit compares an AC voltage whose phase is controlled with a first threshold voltage so as to detect a variation in a conduction state of phase control in the AC voltage, and compares the AC voltage with a second threshold voltage lower than the first threshold voltage so as to detect a zero-cross point of the AC voltage, thereby detecting a conduction period of the phase control. The control circuit outputs an output current according to the duration of the conduction period.

主权项

1. A power supply for illumination comprising:
a detection circuit that compares an AC voltage, whose phase is controlled, with a first threshold voltage so as to detect a variation in a conduction state of the phase-controlled AC voltage, and compares the phase-controlled AC voltage with a second threshold voltage lower than the first threshold voltage so as to detect a zero-crossing point of the phase-controlled AC voltage, thereby detecting a conduction period of the phase-controlled AC voltage; a control circuit that outputs an output current according to the duration of the conduction period; and a bleeder circuit through which an input current smaller than the output current flows during a blocking period of the phase-controlled AC voltage.