Is the led driver malfunctioning? or am I?

the led driver 

Im using an arduino to fade LEDs through PWM. The code works on normal rgb LEDs, but i need it to be much brighter. I bought 3, 3 watt, HPLEDs. they are very very nice and bright. but only work with all colors full brightness... i have attached the arduino pins that controlled the normal rgb LEDs to the driver. but this does nothing different then if the pins were disconnected. also if i dont power up the driver and just plug in the arduino it will change the colors of the leds. but it will be just as bright as the normal ones because its only getting 5 volts instead of 13.5. also the color fade cycle acts really weird. not sure what thats all about or why it even does anything just with the arduino plugged in.

Does anyone know where to get a decent LED driver? i have looked around for days and could not find what im looking for. this looked like my best option but its not working...

thanks for your help.


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frollard4 years ago
I would be interested to see your exact circuit diagram; a friend and I are building 100+Watt RGB pwm leds, and our drivers are active low, so it inverts the pwm frequency. (When the pwm input pin is drawn low it turns the leds on). Looking at your spec sheet, they suggest it's active high (+5v to on, gnd to off)

Remember to tie the grounds together! The arduino gnd pin should connect to the power supply - input side of your driver (s) as well as the wire going to the pwm input, otherwise the driver doesn't know what the 5v input is in relation to.

Circuit Diagram2.png
RexHex (author)  frollard4 years ago
100 watts WOW thats going to be interesting. how do i determine if its active low or high on the arduino?

i was putting the ground coming out of the driver not into it so i will give that a try when i get home. originally i did not put ground in :/

frollard RexHex4 years ago
Ground coming OUT of the driver might actually be switched, in which case when the leds are off it will ignore ground; also, ground on the output side could be isolated (not actually connected to logic ground).
RexHex (author)  frollard4 years ago
So it's better to ground on the IN side so it's always connected? steve is saying that my schematic is not going to work. Well he is saying its wrong. How are you doing your 100w system? You must be using a lot more LEDs and drivers.
frollard RexHex4 years ago
We are using 3w single colour leds for the 45 watt system, and will be using 25 watt rgb for the 100.

The drivers are custom (chip, resistor, and inductor for each channel).
RexHex (author)  frollard4 years ago
where did you find 25watt rgb leds?
frollard RexHex4 years ago
the googles are your friend. :)
frollard RexHex4 years ago
...and yes, ground to the INPUT side of the driver.
Test your PWM, by grounding the PWM pin. If the driver's working, the driver should shut down.

If you raise it high, the driver should go on.

You HAVE connected the grounds betweeen the arduino and the driver together haven't you ?
RexHex (author)  steveastrouk4 years ago
i just got to my room and tested this out. grounding the driver did nothing so it must be the drivers. thankfully i put in a order for 6 luxdrive buck pucks.
they look like they are going to work.
this time i will ground the driver properly.
i think im still going to wire it with 3 drivers controlling two lamps. lamp = 3 3watt leds. i dont understand why this is not going to work.
RexHex (author)  steveastrouk4 years ago
i was not in the beginning.. :/ but i have been lately. it still was not working.

does it matter what ground pin is used?
Did you check your PWM frequency ? It needs 1kHz.
RexHex (author)  steveastrouk4 years ago
yea i was confused about that earlier in the day. thats what i thought my problem was originally.

im using an arduino to control the pwm

it was looking to me like it puts out a 16mhz but someone pointed me to another section of the arduino website that says it puts out 500hz.

the data sheet says that the driver will work on 100hz to 1khz
RexHex (author)  RexHex4 years ago

i dont know why your comment below was removed..
I did it. I wrote something wrong, and there's no edit here.
RexHex (author) 4 years ago
i was hoping to buy one because the projects due on the 10th this month. but what your saying makes a lot of sense. Its safe to say im new at all of this but i have been obsessive from the beginning. now a few months in..

i have a 13.5vdc power supply.(eventually will plug in a 30vdc to power another lamp) and i will put this to the collector of the mosfet. then i would put the LEDs to the emitter. and have the arduino connected to the base so that when it gets a 5v push the gate opens till it stops with the 5v. only to repeat this cycle again and again and again?

what mosfet would you recommend for this?
iceng RexHex4 years ago
Try an IRF510 for 79¢ at JAMECO Electronics
BTW the pin names are different for MOSFETs

This is a rugged device that can turn on a Drain of 1_Amp at a Gate of 5V

Or an IRFZ34N for  a Dollar and can drive a Drain of 10A at a gate of  4V..


RexHex (author)  iceng4 years ago
Thanks for all this information. Im going to continue making LED light installations and will probably start making my own drivers soon. But like I said this is due on the 10th and theres a lot of work to be done and I dont have the time to figure this out right now. Do you think that this is a good driver?

my goal is to have 4 lamps. each has 3, 3 watt LEDs. the drivers only have the ability to power 6 LEDs. so im thinking i will have 3 drivers to control two lamps.

but because these are expensive...

im thinking i should have 3 drivers power 4 lamps by having the second set of lamps come from the same drivers as the other set. is this possible or will the load be to high for the drivers? I think this would make sense.
iceng4 years ago
Make your own drivers using logic driven MOSFETs


iceng iceng4 years ago
RexHex (author)  iceng4 years ago
do you have any idea why the drivers i already bought dont work?
iceng RexHex4 years ago
I suspect the drivers you have use an internal regulator.

And so they will  not react to a PWM Signal.