Compact driver LED for 4-channel, able to drive the 4 colors LEDs  RGBW (Red, Green, Blue, White), smoothly varying the brightness and coloring. It is capable of driving elements with a maximum absorption of 1 Ampere per channel, receive the PWM control signals and to accept a supply voltage of between 6 and 36 volts. The high bearable supply voltage also allows to drive multiple LEDs in series, so as to realize lamps and spotlights; for example, with a voltage of 36 volts is possible to drive a maximum of 36V / 3.4V = 10 white LEDs in series for each channel.

• Power supply: 6 Vdc to 36 Vdc
• Operation: Switching
• Maximum output current: 1 A for channel
• brightness control (dimming): analog and digital
• Number of channels for module: 4
• Dimensions (mm): 27,6x37,3

As the LEDs are to be driven at a constant current and not a constant voltage, in order to obtain the maximum yield and avoid "burning" (recollect that the variation of the current in the diodes is exponential, then small voltage variations cause large variations, is well known to current). The main technique to modulate the current and therefore the brightness is power supply with a PWM signal, namely a form of rectangular wave voltage of which modulates the duty-cycle.

Although to obtain a white light is sufficient to turn on together red LEDs, green and blue (the ratio of the brightness of red, green and blue determines the shades of white, which can be hot or cold) the addition of a white LED allows obtaining whites much more "clean" compared to what can be achieved by mixing the three basic colors; it is also possible to use all four together to obtain a greater light output.

To explain why for the evaluation of a RGBW LED is the forward current must consider, we take a 4-watt LED  distributed power among four LEDs which usually have a driving current of 300 mA (direct current); because the LED on voltage drop varies by color, we have different powers for the various LEDs, namely:

Prred = (2.2 ÷ 2.5V) • 300 mA = 0.66 ÷ 0.75 W Pgreen = (2.5 to 2.8V) • 300 mA = 0.75 ÷ 0.84 W Pblue, White = (3.2V ÷ 3.4V) • 300 mA = 0.96 ÷ 1.02 W

where brackets are indicated the minimum and maximum voltage drops on the diodes. Of the maximum values, we have a total power: Ptot = 0.75 + 0.84 + 2.04 W = 3.63 W then close enough to the allegations.
For LED 12 watt things change a bit ', because the operating current declared amounts to 700 mA; Now the powers become 1.75 W for the red LED, 1.96 W for the green LED, and 2.38 W for white and blue. With these values, the maximum total power becomes: Ptot = 8.47 W. This value is far less than that declared, although it remains a remarkable power. The declared power for RGBW LED is therefore to be understood that maximum driving each LED at maximum power, so with different current values.