10W RGB LED Driver Board Assembly (WS2811 version)

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QTY    Part               Description
3      IC1,IC2,IC3        PT4115 constant current buck driver (soldered)
1      IC4                78L05 LDO
1      IC5                WS2811 (soldered)
3      L1,L2,L3           100uH inductor, 6x8mm, 500ma
3      T1,T2,T3           2N3904 transistor           
3      D1,D2,D3           1N5819 diode
3      R1,R2,R3           0.33R  resistor
3      R4,R5,R6           10K resistor (used to be 4.7K)
3      R7,R8              33R resistor
1      C1                 47uF/50V capacitor
1      C2                 0.1uF capacitor (104)
1      C3                 33pF capacitor (330)


If you experience flickering and you have v6 board, go to the bottom of this page.

v6 of the board is now shipping. The major change is connector header (4 position, larger drill holes.) See image at the end of this page.

All new boards come with 10K resistors instead of 4.7K.

v4 of the board has one additional pad next to T2. The pad allows RGB selection (GRB is default,) see below.

v4 of the board has one additional pad between C2's pads. This is to accommodate 2.5mm and 5mm capacitors, see below.



Solder resistors

Use as little solder as possible.


Cut leads

Cut leads as close to PCB as possible.


Solder diodes

Pay attention to polarity, diode's cathode (stripe) should be on the left side of PCB, pointing towards the LED.


Solder monolithic capacitor, transistors, and LDO

Check markings on components, 78L05 is LDO (IC4,) 3904 are transistors. LDO and transistors should be soldered about 0.1" from PCB, total height should be ~0.3".


Solder inductors

Inductors should be as close as possible to PCB. Apply pressure when soldering, heat for ~2-3 seconds, 2-3 times each lead.

Some inductors may have isolation sticking out on the bottom, trim if that's the case.


Solder electrolytic capacitor

Use PCB to bend capacitor's leads. Pay attention to polarity.


"-" lead should be facing 33R resistors.


Trim leads

Trim all leads, remove excess solder if necessary.



Solder LED

Pay attention to polarity and alignment. LED's "+" (anode) should be on the top (left side on the image below,) close to 0.33R resistors. LED's pins cannot touch GND pour. Lead frame should be cut off (see bottom of this page.)



C2 capacitor

There are 2 different sizes of 0.1uF capacitors that I may ship, 2.5mm or 5mm.


RGB mode

Starting with version 4 of the board, there is one extra pad next to T2 which allows switching collectors of G & R transistors.

This is the default GRB configuration. T1 - green transistor, T2 - red


This is RGB configuration, move C2 to extra pad (G) and C1 to C2's place


Version 6 of the board (Sept 2016)


To fix flickering problem on version 6 of the board, add 33pf capacitor as shown below

Input cap.jpg

Preparing LEDs

Make sure to cut the lead frame off. There should be no connections between colors.

Led-uncut.jpg Led-cut.jpg