Low cost intelligent LED driver for public Lighting Smart Grids

A low-cost 18W intelligent LED driver for energy savings is presented. The intelligent LED driver has a DALI interface that allows it to be included in an upper lighting smart grid. So, it must provide galvanic isolation. The proposed LED driver is based on a two stage scheme with 24V safety voltage. The first stage is based on a PFC Flyback converter operating in the boundary conduction mode, meeting the International Standard IEC61000-3-2 Class C. The second stage is based on 3×6W low-cost and efficient DC/DC buck converters for driving LEDs. The LED lamp has a built-in ambient light sensor that measures the lumen level of the ambient light and a low-cost microcontroller adjusts the emitted luminous flux in order to obtain the desired luminous level of the ambient light contributing to great energy savings. Experimental results validate the circuit proposed.