A high-brightness RGB-LED lamp using palette and PNM current driver

This paper presents a high-brightness RGB-LED lamp of using palette and high-efficiency pulse-number-modulation (PNM) current driver. Target colors of the RGB-LED lamp designed in this paper are specified on a palette of LabVIEW by using a mouse to point it. A complete 24-bit RGB luminance data provided by the palette is split into three separate 8-bit monochromatic commands and sequentially transmitted to an 8-bit microcontroller via RS232 port. Three-channel driving currents of the RGB-LED lamp are all regulated by an 8-bit microcontroller with PNM current driver to keep color stability. Experimental results demonstrate that all color inside the RGB-LED gamut can be designated by user. Moreover, due to the use of PNM switching drive, the power dissipation of the LED driving circuit is extremely low and hence the energy efficiency is improved. The colorful RGB LED lamp can be utilized as a mood lighting fixture in sleeping rooms, hotels, restaurants, hospitals, advertisement walls, and the places required colorful lighting.