LD-4B 17mm buck driver at IOS

I just saw this newly listed 17mm buck driver at IOS

Features:

*Suitable for 1-2-3 18650, 16340 or 18350

*Input voltage: 3-16V

*Drives LEDs up 6.6V

*Output current 2.4A

*Constant current circuit

*PCB Diameter: 17mm

*Total height: 10mm

*Gold plated contacts

*Copper leads already soldered

*Always starts in High mode

*Reverse polarity protection

*The driver does not have an input voltage monitoring function, it is recommended to be used only with protected cells.

You can power 2*XP-L / 2*XP-G2 / 2*XP-E2 in series, MK-R 6V, MT-G2 6V or other higher Vf LEDs while using 2-3*18650 or 2-3*18350 cells in series.

Please Choose:

Modes

1 Mode: High (2400mA)
3 Modes: High (2400mA) - Medium (750mA) - Low (50mA)





The fact that it's only 17mm is the main point of interest. It can run two 3V emitters in series, although I don't know of any two emitter lights per say. It can also drive a 6V MTG, although I don't know why I'd want to drive an MTG at 2.4A.


If anyone has any good ideas for this driver, please post them here.

this would be a good driver to convert my 12 volt ( eight D-cell) Coleman remote controlled lantern over to a MT-G2, and still have good run times on low and medium. ( or a flashlight with a floody MT-G2 to have a great tint but not over driven to high amps. and have better run times.

I saw your thread on th LD-44 Comfy, but wasn’t sure if it was the same as this LD-4B. The picture of The LD-4B isn’t great for comparison. Must be a different resister for the extra 0.4A. I also noticed that the leads come up through the center of the toroid.

Is there any reason this couldn’t be powered from a 12 volt automotive lead acid battery? Also I see it says output current 2.4 amps, how many amps would this draw from a 12 volt lead acid battery.
I’m thinking this might make a good driver for a light for off the grid.

Input current required to do 2.4A output depends on the output voltage. Convert it to watts for the output side, then de-convert it to get the required input current. Assume 85-90% efficiency.

Single XML2, at 2.4A needs about 3.3v. 2.4 x 3.3 = 7.92 watts. With 85% efficiency, the input will be 15% (1.19 watts) higher than the output. Input power should be around 9.1W, divided by 12.4 battery voltage gives around 730mA.

Might be useful for driving 9mm laser diodes, they’re great at 2.40A.

Should be scoped for ripple and current spikes though, laser diodes aren’t as forgiving as LED’s.

Hi,

Off-topic: I noticed that your location has changed to “Pittsburgh”… are you on-campus already? Howzit going :)?

Thanks

Yup, school has started and everything is just as I had imagined what college life would be, thanks for asking ohaya!

I really like the robotics club, it has a nice machine shop with a milling machine and a lathe. I’ll be able to work on my personal projects there. :slight_smile:

That (the machine shop) sounds like fun, but don’t forget why you’re there. Oops, starting to sound like a parent… sorry :)!!

Thanks Dad! :stuck_out_tongue:
Yup, I do prioritize my academics over anything else, or else I would have been modding a flashlight a day. :party:

Have you not heard the long held view of medical practitioners?

Modding a flashlight a day keeps the doctor away.

Nothing like a healthy lifestyle.

After thinkin' on this for a while, this driver probably isn't the best choice for that kind of thing. It's likely compromises were made to get the size down, and a larger driver would make sense in an application where space isn't the most critical factor. The 'new' 32mm DRY driver would probably be more efficient in the same setup, something to do with the driver architecture I don't fully understand, but it uses a beefier inductor, and two big FETs instead of one tiny one (synchronous vs. ...whatever the name is for the version used on this driver, with just one FET & a diode).

Also, using more LEDs in a series/parallel circuit will further improve efficiency, both in the driver and in the LEDs. Adding LEDs in series raises the output voltage closer to the input which helps the driver somewhat (as long as the Vf will always be less than the minimum input voltage), and adding series strings in parallel divides the total driver output between them, and LEDs at lower currents can have drastically better efficiency.

How many leds will the 32 mm dry driver run and how many amps will each one get from a 12 v lead acid battery

Stock output is 3.5A, though it has multiple resistors, you can remove one or some to lower the current to whatever you want. It's also a buck driver so the total forward voltage for whatever LEDs you use will have to be less than the minimum input voltage if you want it to run at the driver's full output.

Same math as earlier applies, it's easy to figure out. I use Match's Vf graph here, it's close enough for estimates like this. There are other graphs out there for other LEDs.

Just putting it out there if there was any interest in this driver starting on low instead of high. It can be done but Hank would have to get another batch made.

http://www.cnqualitygoods.com/goods.php?id=2173

I was aware of this driver CC but it is supposedly 2 amps against the IOS driver 2.4 amps.

Same driver with different firmware and a different sense resistor (which most of us lunatics will 'adjust' anyway). :)