ShadowNoob
New member
Guess this thread is dead
DIY LED driver for reef lighting
- Thread starter der_wille_zur_macht
- Start date
The SN3910 is a great led driver tan can be run directly off rectified AC. So you can run something like 30 leds on it no problem.
Also, I am making LM3429 led boards. Great boost boards, with a max vout of 40v at least, but can go up to 70v with care in the components.
They get 94% efficiency across a wide range of voltages.
Also, I am making LM3429 led boards. Great boost boards, with a max vout of 40v at least, but can go up to 70v with care in the components.
They get 94% efficiency across a wide range of voltages.
I'm just going to point out something that's been covered more than a few times, but needs to be reiterated from time to time for the newbies and inexperienced hobbyists that reed these forum posts.
Exceeding 50 volts on a DIY LED build is extremely dangerous to the DIY'er. Voltage over 50 volts presents a serious risk of fatal electrocution should you touch a live wire or have an led shorted to the heatsink, which is very common and often the lights still work just fine despite the short.
Exceeding 50 volts on a DIY LED build is extremely dangerous to the DIY'er. Voltage over 50 volts presents a serious risk of fatal electrocution should you touch a live wire or have an led shorted to the heatsink, which is very common and often the lights still work just fine despite the short.
I apologize. I assumed anybody reading this thread would have ample knowledge of how to handle large voltage, as they would need a reflow oven to use either of the chips I posted.
The LM3429 is a boost driver, so it only provides however many volts are needed. So there is little risk of electrocution.
Is this thread dead? I don't think DWZM has been online for more than six months.
anyway, I'm working on making a driver using the 3066 but none of the documents or images from 2009 are available or viewable on my tablet. I took a schematic from the driver manual and have been modifying it accordingly but there are things mentioned in the initial couple pages that don't exist in ky schematic.
I'm not going to post. Any specs yet in case this is dead,but if someone who can assist could reply or pm me I have it available.
Lastly, I know. This was a discussion thread but it's painful scrolling through 108 pages just to stay relevant with a reply especially since only the first 15 or so pages were really crucial. Someone should have made a closed thread sticky with all the PSU Led and driver DIY information seperate from the discussions. Dwzm did a good job with links to other threads in his first post,but without a recapture when the bulk of the discovery is done it has a diminished effect.
That being said this website is absolutely one of the best places on the Internet for this type od DIY
anyway, I'm working on making a driver using the 3066 but none of the documents or images from 2009 are available or viewable on my tablet. I took a schematic from the driver manual and have been modifying it accordingly but there are things mentioned in the initial couple pages that don't exist in ky schematic.
I'm not going to post. Any specs yet in case this is dead,but if someone who can assist could reply or pm me I have it available.
Lastly, I know. This was a discussion thread but it's painful scrolling through 108 pages just to stay relevant with a reply especially since only the first 15 or so pages were really crucial. Someone should have made a closed thread sticky with all the PSU Led and driver DIY information seperate from the discussions. Dwzm did a good job with links to other threads in his first post,but without a recapture when the bulk of the discovery is done it has a diminished effect.
That being said this website is absolutely one of the best places on the Internet for this type od DIY
Looks like I'm too late for this thread but I'll ask this question anyway. I have 5 LM3409's that are controlled by a single digital pot that seems to have an issue. I can select the individual drivers, and the more I turn on, the more voltage seems to be injected into the iAdj pin. Any ideas? I'm wondering if I need lower value resistors to create a stiffer potential divider and maintain the desired dimming voltage. Currently using 10K on the 5V end, and a 5K digital pot to GND giving a max of 1.667V Seeing as the iAdj pin is internally clamped I might bring that 10K down to 1K and provide a few mA instead of the 0.3mA it currently has. Thoughts?
Can you post up a schematic of the digital pot circuit? I've built plenty of LM3409 based drivers using conventional 250k ohm potentiometers for analog dimming. Since digital pots should behave similarly to their analog cousins, may be a "higher value" digital pot will cure your problem?
Post a schematic please?
I think your pictures or attachments are being blocked by the Mods until your post count is a little bit. I'd love to be able to help you, but without being able to see what you're doing, it's impossible right now.
Hi guys,
I am working on a project, using the LM3409 buck converter. I saw that you had some interesting discussions going on about that chip, and I wondered if you could have a look at my problem?
The constraints are:
Vin 12 - 40V, Vout: 9V, Iout: 1-5A, frequency: approx. 500kHz.
Shunt: 47m Ohms
Coff: 2nF, Roff: 220 - 10k Ohms.
I simulated the project, and everything was fine.
When I built it, I saw that there are several very short on- and off- switching states within one free-wheeling cycle. The time between them is approximately the off-time.
Now I red the datasheet, and that says, that the LM3405 switches the + and - comparator inputs with every cycle - leading to an offset of 24mV.
-> the current has to decrease by more than 0.5A before the next switching cycle - if a shunt of 47m Ohms is used.
This is a problem, because it leads to a very high inductor current ripple and to many switching cycles, which leads to a thermal problem of the switch.
If the current is reduced, or the off-time is reduced, the switching cycles within one free-wheeling period become less.
Does someone have an idea where this problem might come from and what could be done about it?
Did anyone have a similar problem?
Thanks,
Philipp
I am working on a project, using the LM3409 buck converter. I saw that you had some interesting discussions going on about that chip, and I wondered if you could have a look at my problem?
The constraints are:
Vin 12 - 40V, Vout: 9V, Iout: 1-5A, frequency: approx. 500kHz.
Shunt: 47m Ohms
Coff: 2nF, Roff: 220 - 10k Ohms.
I simulated the project, and everything was fine.
When I built it, I saw that there are several very short on- and off- switching states within one free-wheeling cycle. The time between them is approximately the off-time.
Now I red the datasheet, and that says, that the LM3405 switches the + and - comparator inputs with every cycle - leading to an offset of 24mV.
-> the current has to decrease by more than 0.5A before the next switching cycle - if a shunt of 47m Ohms is used.
This is a problem, because it leads to a very high inductor current ripple and to many switching cycles, which leads to a thermal problem of the switch.
If the current is reduced, or the off-time is reduced, the switching cycles within one free-wheeling period become less.
Does someone have an idea where this problem might come from and what could be done about it?
Did anyone have a similar problem?
Thanks,
Philipp
common ground?
common ground?
Hi,
I'm using the CAt4101 board with an arduino.
My LED strings don't turn on. I think the issue might be the ground but I'm just not sure how to wire it to the arduino and the power supply.
I have a 24v 5A power supply with 100-240v input. It has V- V- V+ V+, do I connect the ground pin on the arduino to the V- on the power supply?
I fried an arduino by connecting the digital ground to V- (I wasn't paying attention)...
Thanks
common ground?
Hi,
I'm using the CAt4101 board with an arduino.
My LED strings don't turn on. I think the issue might be the ground but I'm just not sure how to wire it to the arduino and the power supply.
I have a 24v 5A power supply with 100-240v input. It has V- V- V+ V+, do I connect the ground pin on the arduino to the V- on the power supply?
I fried an arduino by connecting the digital ground to V- (I wasn't paying attention)...
Thanks
Yes- Make sure that your CAT4101 board & the Arduino's ground pin all connect back to the V- terminal of your power supply.
