RGB LED Colour Mixing

 To implement different patterns of RGB color mixing, each LED die needs a dedicated signal for dimming. One method is using a single driver that has three or more channels and is capable of controlling each channel separately for dimming. The other is using three drivers to provide power and implement dimming function respectively on three channels. Obviously, the former method uses fewer drivers and is suitable for the applications such as backlighting and display matrix that work on lower current and a large number of LEDs. The latter one can be used in high power applications such as decoration lighting.

In addition, a MCU is required to drive LED driver to carry out dimming function and store color configurations of LEDs. For those applications that require more accurate color mixing, color and temperature sensors should be used to monitor the mixed color output and provide feedback.

LEDs used in RGB color mixing are totally depends on application requirement, either High Brightness or High Power LEDs can be used in these applications. The main suppliers include Cree, Broadcom, Lumex and Vishay. LED driver are available from ON Semiconductor, TI and Linear Technology.

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