DIY LED driver for reef lighting
- Thread starter der_wille_zur_macht
- Start date
question about the driver with the CAT .... what is the frequency you guys are using ? I am at 1200Hz and the dimming is not that great ... when I am at the value 1 (max is 255) the led still pretty bright ! (little more than a bright moonlight). My concern is I can't go less than 1200Hz because the uP I do use (PIC18F4620) is running at 30Mhz (need this speed to control my TFT screen with touch screen)
Individual CAT 4101 control?
Individual CAT 4101 control?
Quick Question with the CAT 4101 Triple. I'm planning on building a setup which will use 12 XP-G warm whites, 12 XP-E Royals and up to 6 XP-E blues. I only need 5 CAT's to run these.
I have already redesigned the triple board to have separate PWM controls for each CAT with all currents at 700mA. I have also included 'blank' SMD tabs on the bottom layer that can be soldered together to connect two or all three back together. I've attached the PWM mod below if anyone is interested in checking it out for errors.
Would it be worth it to modify the board so that each individual CAT can have a separate PWM AND the resistors needed to modify the voltage supplied to each group? For example, the XP-G's running at 1A and XP-E's at 700mA? I realize this might take more than a voltage drop to accurately supply each group of LEDs. Just looking into methods to reduce purchasing costs by combining boards and components as needed.
Thanks!
Individual CAT 4101 control?
Quick Question with the CAT 4101 Triple. I'm planning on building a setup which will use 12 XP-G warm whites, 12 XP-E Royals and up to 6 XP-E blues. I only need 5 CAT's to run these.
I have already redesigned the triple board to have separate PWM controls for each CAT with all currents at 700mA. I have also included 'blank' SMD tabs on the bottom layer that can be soldered together to connect two or all three back together. I've attached the PWM mod below if anyone is interested in checking it out for errors.
Would it be worth it to modify the board so that each individual CAT can have a separate PWM AND the resistors needed to modify the voltage supplied to each group? For example, the XP-G's running at 1A and XP-E's at 700mA? I realize this might take more than a voltage drop to accurately supply each group of LEDs. Just looking into methods to reduce purchasing costs by combining boards and components as needed.
Thanks!
Last edited:
I have been following this thread for some time now and want to thank you all for your efforts. I ordered some CAT4101s but am yet to order LEDs. I had decided to order cree XP-Gs but now the cree XM-Ls seem tempting... There is a mention in the CAT4101 datasheet that they can be run in parallel to run a LED string with more than 1 Amp. Would it mean just connecting the led pin of 2 CAT4101s together. What happens to the PWM? should the same signal be applied to both CAT4101s? I have some 1W /350 ma leds to experiment on. Was thinking of supplying 150 ma each through 2 CATs to see if a total of 300 ma is output. Please let me know your thoughts.
TheFishMan65
New member
I had not thought of PWM, but I think they could be different. However, you are probably better keeping them the same so heat issues are similiar in both chips.
Simon I think you and I are thinking a like. Is this the design you have in mind?
Then replicate the everything but the 7805 and C1. How many times are people interested in? I figure and even number and have two PWM (white and royal blue). Seems like a waste to have to add the 5V circuit every time, so I lean torward a larger number, but most people are getting the 24V at 6.5 amps supply from mjpa. Which might support six if not at a true 1 amp (upto about 866 ma). Any other good power supplies out there?
From this diagram, pin 1 is left open, but it is use for dimable, correct?
Thanks.
ghellin
New member
ok my driver PCBs are in and I have a few questions.
1. the power supply listed in this thread over and over says no longer available so what is the cheapest alternative?
2. I will be running 48 LEDs off of 4 different PCB's for dimming with an arduino uno. so how many power supplies would I need?
3. I will be running XP-Es and XP-Gs what resistors should I use to run at 1000 mA? (a mouser part# would be best here if possible)
4. And finally is this the cat 4101 I want from Future http://www.futureelectronics.com/en...-linear-mode/Pages/4593497-CAT4101TV-T75.aspx
Thanks in advance!
And I do need one more driver PCB if anyone has any.
1. the power supply listed in this thread over and over says no longer available so what is the cheapest alternative?
2. I will be running 48 LEDs off of 4 different PCB's for dimming with an arduino uno. so how many power supplies would I need?
3. I will be running XP-Es and XP-Gs what resistors should I use to run at 1000 mA? (a mouser part# would be best here if possible)
4. And finally is this the cat 4101 I want from Future http://www.futureelectronics.com/en...-linear-mode/Pages/4593497-CAT4101TV-T75.aspx
Thanks in advance!
And I do need one more driver PCB if anyone has any.
bradstokes
New member
I ran into the same problem as I am starting my build as well.
1. After some serious looking, found this http://www.circuitspecialists.com/prod.itml/icOid/9590
2. 48 / 6 = 8 channels of leds * 1A = 8 amps, so at least 2 of those 6.5 amp power supplies
3. Someone else might want to help out here, but according to the datasheet for the cat4101 you need a 549ohm resistor, I think this would be acceptable, from mouser, 660-RK73H2BLTD5490F
4. That is the exact cat4101 I just bought.
@shikhyung : Yes pin 1 is for pwm dimming, however, if you don't want to dim just tie it to 5v.
Hope this helps.
Brad
Last edited:
I know it can be daunting but try searching and reading DIY LED threads... specially the humongous Write-Up.
This thread is about the DIY driver. :beer:
ghellin
New member
bradstokes
New member
Just got in my order from Mouser,
I ordered it yesterday about 2:00pm CST. Pretty fast even for being in the same state. Man these components are tiny! :fun2:
Brad
I ordered it yesterday about 2:00pm CST. Pretty fast even for being in the same state. Man these components are tiny! :fun2:
Brad
pleas do accept my apologise, as I'm not a 100% elec. tech, but don't have 2 left hand and not shy to learn as I do lots of DIY projects, and build already one DIY LED unit.
when building the first LED unit it came with a driver (se picture), but now want to build the driver to save some $
as it is almost the same as the one mentioned above, I'm locking for some info, so it makes more sense for me, as I'm more like, part A needs to go in spot 1 and part B in spot 2
so could need some help on revers engineering this thing, so I understand it better (as schematics is a bit hard for me)
I have 100 CREE led's that I want to start putting together, I previously both this driver for $ 65, however in components it is only about $ 15 I think
so here we go:
A= negative from power supply (24V)
B= positive from power supply (24V) the bridge in between is in case I want to put a electronic dimming function on)
C= connections for a regular pot dimmer (that's on it now)
D= negative to LED
E= positive to LED
1= what the hack is this, and what douse it do
2= what is this ? is this the resistor (I found a online resistor calculator to find out what one I need) but is this the resistor yes / no) if no what is it and what douse it do !!
this one sits between the pin 2 from the driver chip and the negative
3= what is this one ? when locking with a magnifying glass it is printed don it T680 "“ what douse it do? ---- this one goes in the middle from pin 4 on the driver chip to the positive from the LED's
*= 5 V DC voltage regulating chip 7805 CG
+= CAT 4101 led driver from onsemi
plan is to build one of these units to drive my XP-G's and one for my XP-E's (6 led's for each LED driver chip cat 4101)
reason why I want to stay whit this driver is because I'm not a electro tech, and when I can re build this driver I have something I can copy right on the table, as schematics dot tell me anything, for me it is more like: I need 1 of part A and put it there, I need 1 of part B and put it there
TheFishMan65
New member
I don't understand a bridge at B. You would use the PWM for dimming.
I htnk a lot of theunknonw parts ar capacitor for stabilizing the voltage. Sorry not real familiar with the 3 board version.
1) llok like a cap on the 5 volts.
3) I am guessing this is a 24 volt cap.
2) thius is the sense resirotr should go to ground.
ghellin - thre resitor depends on the board it has to match the board layout. There is ahcart in the datahseet that tells ohm for a varietyof currents.
I htnk a lot of theunknonw parts ar capacitor for stabilizing the voltage. Sorry not real familiar with the 3 board version.
1) llok like a cap on the 5 volts.
3) I am guessing this is a 24 volt cap.
2) thius is the sense resirotr should go to ground.
ghellin - thre resitor depends on the board it has to match the board layout. There is ahcart in the datahseet that tells ohm for a varietyof currents.
B is there in case you have a PWM control (than the conection is going in B, as I dont have the PWM yet it is bridged)
I now have a regular pot to dim (never dimed the ligets, ony the first 3 weeks, I went from 50% to 100% light output
ghellin
New member
Sorry I am not that great with this. I am using the 3 cat4101 boards I plan on using all XP-Gs and XP-Es. I will use a micro controler the arduino uno to create sunrise sunset. I want the driver boards able to push the LEDs up to 1000mA. But plan on keeping them at 700mA. I can't find the data sheet to which you are referring. If anyone has already built a 3 cat 4101 driver with a 1000ma drive capacity you parts list would greatly help thanks.
The only parts you have to change to run the 3 CAT4101 driver at 1000mA are the resistors (R1, R2, R3). As bradstokes already stated, you will need 549 ohm resistors instead of 768 ohm resistors (768 ohm resistors would allow a max current of 700mA).
Last edited:
