LED DRIVING POWER SUPPLY APPARATUS AND LED LIGHTING APPARATUS

摘要

An LED driving power supply apparatus and an LED lighting apparatus is provided in which stable dimming is realized even when dimming is performed in a range that includes a light-off state. A power conversion control circuit controls the on time or switching period of a switching device in accordance with a feedback control signal input through an insulating member, operates as a PFC converter, and controls power supplied to the LED. A dimming control circuit includes a constant current control circuit, a constant voltage control circuit, and an OR gate circuit. When the external dimming signal is a signal specifying normal lighting, the constant current control circuit maintains a current supplied to the LED at a target current. When the external dimming signal is a signal specifying a minimum luminance, the constant voltage control circuit maintains a voltage applied to the LED at a target voltage.