LIGHTING APPARATUS AND LUMINAIRE

摘要

Lighting apparatus includes: AC/DC converter which converts AC voltage Vac to DC voltage Vdc; DC/DC converter which converts DC voltage Vdc to a DC voltage to be applied to LED; and detection circuit which detects AC voltage Vac. DC/DC converter includes switching element, and control circuit that performs a control of repeatedly turning on and off switching element in a boundary conduction mode. Control circuit performs the control under which ON time Ton is kept from exceeding an upper limit that is previously determined, and raises the upper limit when AC voltage Vac detected by detection circuit falls below a predetermined value. ON time Ton is a period of time during which switching element is kept ON.

主权项

1. A lighting apparatus which supplies a current to a solid-state light-emitting device, the lighting apparatus comprising:
an AC/DC converter which converts an AC voltage to a first DC voltage; a DC/DC converter which converts the first DC voltage to a second DC voltage to be applied to the solid-state light-emitting device; and a detection circuit which detects at least one of the AC voltage and the first DC voltage, wherein the DC/DC converter includes a switching element, and a control circuit that performs a control of repeatedly turning on and off the switching element in a boundary conduction mode, and the control circuit performs the control under which an ON time is kept from exceeding an upper limit that is previously determined, and raises the upper limit when the at least one of the AC voltage and the first DC voltage detected by the detection circuit falls below a predetermined value, the ON time being a period of time during which switching element is kept ON.