Lighting apparatus and lighting fixture using same

摘要

A lighting apparatus includes a chopper circuit and a control circuit that controls the chopper circuit. The control circuit includes a determining unit that determines a duty ratio of a dimming signal, and an output control unit that outputs a drive signal. The control circuit outputs a drive signal from the output control unit according to a result of a determination by the determining unit and causes the solid state light-emitting element to be lighted in a normal mode. In the charging mode, the control circuit sets an average value of a current flowing through an inductor to be higher than in the normal mode and charges a smoothing capacitor until a voltage across the smoothing capacitor reaches a prescribed voltage. When power is supplied, the control circuit charges the smoothing capacitor in the charging mode and subsequently lights the solid state light-emitting element in the normal mode.

主权项

1. A lighting apparatus comprising at least one chopper circuit that comprises a switching element, an inductor, a diode, and a smoothing capacitor, and a control circuit that controls the at least one chopper circuit,
wherein the control circuit comprises: a determining unit configured to determine a duty ratio of a dimming signal that instructs a dimming level of a solid state light-emitting element provided in a subsequent stage of the at least one chopper circuit; and an output control unit configured to output a drive signal for driving the switching element, wherein the control circuit has a normal mode and a charging mode as operating modes, wherein the control circuit is configured to output the drive signal from the output control unit according to a determination result by the determining unit and to control the at least one chopper circuit to light the solid state light-emitting element in the normal mode, and configured to set an average value of a current flowing through the inductor to be higher than an average value of a current flowing through the inductor when the solid state light-emitting element is dimmed at a dimming level that is a lower limit of dimming in the normal mode, and to control the at least one chopper circuit to charge the smoothing capacitor until a voltage across the smoothing capacitor reaches a prescribed voltage that does not light the solid state light-emitting element in the charging mode, and wherein the control circuit is configured to control the at least one chopper circuit to charge the smoothing capacitor in the charging mode when power is supplied to the lighting apparatus, and to subsequently control the at least one chopper circuit to light the solid state light-emitting element in the normal mode.