20W RGB LED Driver Board Assembly (RGB version)

BOM

QTY    Part               Description
3      IC1,IC2,IC3        PT4115 constant current buck driver (soldered)
1      IC4                78L05 LDO
1      IC5                74HC86 (soldered)
3      L1,L2,L3           100uH inductor, 6x8mm, 500ma        
3      D1,D2,D3           1N5819 diode
3      R1,R2,R3           0.33R  resistor
3      R4,R5,R6           10K resistor (used to be 4.7K)
1      R7 or R8           0.33R or 0R resistor
1      C1                 47uF/50V capacitor
1      C2                 0.1uF capacitor

Polarity

Input polarity is determined by soldering 0R (0ohm) resistor (one black band) either as R7 or R8.

For positive input, meaning positive input voltage (3.3V-5V) will turn the LED on, solder 0R in R7 position. Input voltage cannot exceed 5V.

For negative input, meaning shortening input to GND will turn the LED on, solder 0R in R8 position. LED will be off when input is open or at 3.3V-5V. This configuration is often used with open collector/drain drivers designed for common anode (+) lights.

Older kits were shipped with 0.33R resistors instead of 0R and that's why R7/R8 on all images is 0.33R and not 0R.