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1  Using Arduino / Project Guidance / Re: 3w RGB color bar (BOM w/ TLC5940, Fets, UNL's on: July 06, 2013, 02:34:59 pm
Can anybody validate this design for a single 3w RGB using a mini 3 ch RGB controller, see attachment.
2  Using Arduino / Project Guidance / Re: 3w RGB color bar (BOM w/ TLC5940, Fets, UNL's on: February 16, 2013, 12:55:26 am
How about this config to drive 1x3wRGB (r=2.5v, b/g=3.5v) at 350ma per color

(eg. 3chRGB Controller output for Red(only) from 12vDC > 3ch RGB controller(each separate output to) > NPN > ZXLD1352

12v+ ----47k 5% .25w----\  prevent flicker when power on
R  -------10k -------------/ (gate) BC848(npn)-collector -> ADJ(zxld1352)
B                                   (emitter)--GND           

Grnd  ---- power grnd of zxld

Any better way or different part configurations for doing so?  The ZXLD1352 has 1000:1 dimming vs 100:1 for the 1350 (assuming would this give better dimming spectrum)
3  Using Arduino / Project Guidance / Re: 3w RGB color bar (BOM w/ TLC5940, Fets, UNL's on: February 12, 2013, 02:23:52 pm
Would I a pull-up in this scenario, like a 10k pull-up between ADJ and controller's output?   
would it be close to this model below?
(each color 350ma)

3ch RGB controller output1(12v >)  -> 10kpull-up -> Adj 
10kpullup -> c1=100nF -> Grnd

12v -> Vin -> Rsense(.1ohm) -> RGB(eg.Red) -> 47uH -> Lx

I think also it might better to the use the ZXLS1350(350ma) vs 1360(1a)
4  Using Arduino / Project Guidance / Re: 3w RGB color bar (BOM w/ TLC5940, Fets, UNL's on: February 09, 2013, 03:07:15 am
since my output from the 3chRGB controller... each color output ranging from 12v and below, I will need to regulate before connecting to the ADJ pin bc the zxld1360's ADJ pin max is +6v. It seems the only way to do so is use a NPN transistor so the 1360 only receives voltages from 0 to +6 volts, is this the correct way to do this?  In reading the specs, do I regulate the NPN operational at +6v or is it +2.5v (according to the DC voltage method) ?
(1360's specs)
Driving the ADJ input via open collector transistor
The recommended method of driving the ADJ pin and controlling the amplitude of the PWM waveform is to use a small NPN
switching transistor as shown below:
This scheme uses the 200k resistor between the ADJ pin and the internal voltage reference as a pull-up resistor for the

• Drive with DC voltage (0.3V < VADJ < 2.5V) to adjust output current from 25% to 200% of
• Drive with PWM signal from open-collector or open-drain transistor, to adjust output current.
• Adjustment range 25% to 100% of IOUTnom for f>10kHz and 1% to 100% of IOUTnom for f <
• Connect a capacitor from this pin to ground to increase soft-start time. 
(Default soft-start time = 500µs. Additional soft-start time is approximately 500µs/nF)
5  Using Arduino / Project Guidance / Re: 3w RGB color bar (BOM w/ TLC5940, Fets, UNL's on: February 07, 2013, 11:39:46 pm
ah, I can see now how it would not be possible... which is why vendors use individual colors led in their washes, floods and bars as it is overall less expensive on the hardware side. I was wondering why RGB's are hardly used in out of the box led fixtures, although, it's just a bit more of a task when having multiple RGBs per fixture.  Alternatively, If I could use a multi-channel IC like the TLC5940 would probably be the preferred route, but, it would need to accept 3 pwm outputs from DMX RGB controller, not sure if it's possible.

In using a switching regulator per color per RGB, what's consider the best choice considering dimming to be important, does the zxld1360 suffice or what other IC's, Fets..etc  I know many others have gone this route so curious as to what would be the best /cost effective way... ULN2003,LM317...etc

I had a lapse,  here's what I would need to do with 1360, as stated by John....
" Yes, you can run the Open Collector PWM signals from your controller to the "ADJ" pin of the ZXLD1360."
6  Using Arduino / Project Guidance / Re: 3w RGB color bar (BOM w/ TLC5940, Fets, UNL's on: February 07, 2013, 06:42:30 pm
Thankyou John... that's right, can't do series with CA, I've read so much material I keep forgetting the basics, althought, is this regardless of the driver I use or is there a circuit build possible for CA in series?
7  Using Arduino / Project Guidance / Re: 3w RGB color bar (BOM w/ TLC5940, Fets, UNL's on: February 07, 2013, 05:44:28 pm
With the ZXLD1360, can I directly connect pwm output from an 3ch RGB controller to the 1360?  They're not logiclevel (I think).  If I limit current to 300ma per color, could I then take the Blue from 3 of the RGB's connect to single 1360, do the same for RED, Green...thus needing only 6x1360s for a fixture with 6x3wRGB?  Aka, run colors in series to each 1360 chip separately.
8  Using Arduino / Project Guidance / Re: IC w/ individual PWM for RGB high current application on: February 07, 2013, 04:59:31 pm
Great find on the LM3406... then it would regulate the current appropriately to each color based on the pwm input?  With 6x3wRGBs (18w total per fixture), since LM3406 is rated at 2a could I use 1 per color and only use 3x3406's per fixture?  Aka, 1x3406 blue, 1x3406 green, 1x3406 red.  I don't need multiplexing but only control per color.   I want to use the pwm output from an RGB DMX controller to each IC, as the 3406 will do both logic and voltage regulated pwm signaling...will this work?  

I'm a bit confused on the difference between the 3406 and CAT4109...

With the TLC5940, can I input the pwm signal voltage from the pwm-output of RGB DMX controller?   Basically, I need an IC that can direcly take pwm from an 3CH RGB controller decoder, prefer to use 1 ic per color and/or 3 ic's per fixture versus using 1 for each color on each RGB then be 18 regualtors/ic's (in using LM317's).  I believe the pwm coming from the 3ch RGB controller is 12v > so input voltage on IC needs to be 12v at min, otherwise, would need to regulate voltage down to appropriate input voltage.

I think I'd need another voltage and/or current regulator (mosfet)along with the 1360 to pull it off...
9  Using Arduino / Project Guidance / IC w/ individual PWM for 3wRGB (Cat4109 vs LM3406) on: February 06, 2013, 02:03:36 pm
I'm looking for the most efficient(least amperage) and cost effective way to power several 3w RGBs (300-350ma)utilizing 3 Ch RGB DMX controller. Aka, output from controller will have 3 wires (RGB) and ground from 12v controller and want these to connect to the IC (assume it needs 3 separate individual pwm inputs&outputs -- cat4103..etc).  Is this possible, or is there a DMX to PWM module?  if so, I know I'll need to amplify the output current of each channel on the IC to 300-350ma.  Using LM317s per channel might be the most cost effective, but, certainly not most efficient with 3v dropout per module.
10  Using Arduino / Project Guidance / Re: 3w RGB color bar (BOM w/ TLC5940, Fets, UNL's on: February 01, 2013, 05:46:43 pm
Posting my learnings here today,

Just discovered WS2803D (in place of the TLC) and it's datasheet says it can handle up to 12V directly so no need for the NPN's in some cases, can drive 6RGB's per chip, serial interface

Here quick breakdown I could use for either 5-6 RGB3w fixtures:

WS2803 = 18 channels (1 IC needed)
TLC5940 = 16 channels (2 IC = 32 channels)
74HC595+ULN2803 (pair) = 8  ( 3 pairs of IC = 24 channels

Using the WS2803 chip (or chips) you don't use PWM to talk to them but a form of serial using 2 digital pins. These 2 pins will talk to all the WS2803 chips (not 2 pins per chip) as there control pins are daisy chained together CKI > CKO & SDI > SDO   (not sure I understand this yet)
The VCC pin on the WS2803 needs connecting to the +5V pin on the UNO and the GND pin needs connecting to the GND pin on the UNO and to the 12V ground. The CKI and SDI pins need connecting to a couple of the UNO's digital pins as these program the WS2803 chip(s).
The IREF needs connecting to the shared ground (preferably not ground through the UNO as I'm not sure of IREF output level)
A couple of capacitors to just reduce potential electrical noise and smooth out loads. I would try one 16V 10uF electrolytic and one 16V 100nF ceramic per WS2803 connected between VCC & ground close to the WS2803

I need to learn more about the high current output of this 2803D IC... sounds like a possible upgrade from the TLC

11  Using Arduino / Project Guidance / Re: 3w RGB color bar (BOM w/ TLC5940, Fets, UNL's on: February 01, 2013, 03:52:49 pm
Would there be any advantage to use this circuit below using ULN2803's ?  Would only need 2 x 2803's  vs 15x1360's (3 per RGB for 5 RGB fixture) is that correct?  My concerns are is performance change w\ multiplexing...etc.  You can reach 300ma with 3v on the 2803's if you look at the spec sheet.

 I did order a few 10w RGB, once I get the 3wRGB driver figured out I'l just change to accommodate the 10w...  I'm new into this but tech enough and detailed so that it's pretty fun doing so....
12  Using Arduino / Project Guidance / Re: 3w RGB color bar (BOM w/ TLC5940, Fets, UNL's on: February 01, 2013, 12:33:13 am
After look up the ZXLD1360, that's exactly what I need... (also HV9910 possible supposedly), would need one per 3wRGB.  Do you have a drawling of your circuit available, what parts would I need besides the 1360 and 5940, capacitors, resistors..etc  for 350ma per ch for each RGB?  Would the flow go as folllows:  12v(power) > 1360 > TLC5940 > RGB led  and/or what pieces hang off of any of these?   R1, R2, uf's...etc

Thank you, this will be such a big help!

13  Using Arduino / Project Guidance / Re: 3w RGB color bar (BOM w/ TLC5940, Fets, UNL's on: January 31, 2013, 02:31:15 pm
Thankyou... I tried following the threads (gets a bit confusing for me) not great at reading circuits, moreless better at drawlings ,lol.   I'll look up the ZXLD1360 and do some learnings about it.  If I do use the TLC  it would give me multiplexing capabilities or individual control over each RGB within fixture (nice to have), but, could go either way.  Have you used the ZXLD1360  ?     
14  Using Arduino / General Electronics / Re: Using BC327 instead of BC337 but not working as expected? on: January 30, 2013, 08:24:16 pm
Hello...  I was putting together 5 * 3wRGB(350ma per color) to create single RGB wash fixture and wanted to use the TLC5940, seen you guys went thru some trial/errors in the post.  I'm techy but not with electronics so much, does anyone have the exact circuit I could see or the BOM and parts.   Knowing the TLC can't reach 350ma and there's a solution around it, as was discussed in this thread early but can anyone summarize this recent build?  It was a bit hard for me to follow at 100%.... Thanks!
15  Using Arduino / Project Guidance / Re: 3w RGB color bar build-out on: January 30, 2013, 05:33:56 pm
I know the TLC5940 can only do 120ma per channel 16 which is 5 RGBs but I'd have to mosfet p (I believe) do regulate current before entering the TLC, does this sound right?  It would be more feasible to just do 5 RGBs(3w) per fixture and therefore only needing single TLC per fixture, however, wouldn't I need a mosfet per color so in this case 15 of them?

I suppose you must run these 4pin 3w RGB in parallel?  or could it done in series?

What need to find is several circuits used with high voltage/current LED drivers..etc
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