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Does anyone have a working schematic for a boost that can do 38V output @ 2A ?

rhd

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Input specs 9V to 12V and output needs to be 38V @ 2A (can be constant current or constant voltage).

I ordered a (genuinely) 11,000 lumen LED that requires quite high voltage. I'm going to run it from 3S3P Panasonic 18650s, but that will still require quite a bit of boosting.

There are a number of drivers out there that can handle it, and I've ordered this in the meantime:
DC DC 250W Constant Current Boost Step UP Module Mobile Power Supply LED MAX 10 | eBay

However, I need something smaller. As a contingency plan, I'll reverse engineer the PCB of that ^ and try to shrink it by double-siding and violating good design rules. But I'd rather not have to do that. It can be painstaking, and if it turns out to be a 4 layer board, I'm screwed.

EDIT: As I look at that board a little closer, I'm left wondering if perhaps it's an aluminum board (implying 1 side) rather than just a white standard PCB? I see that the blue pots are surface mounted, which you'd probably only do if you couldn't use through-hole for some reason (like it being a metal board). If it's a 1-sided board, then I'm less opposed to having to reverse engineer it, and maybe I should just stick with that solution.
 
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This post is of no help, but that is the smallest I've seen. I bought some 600W "10A" boost power supplies to push some 100 watt LED's at 38VDC and the most current I could get out of each one was a bit more than 3 amps when driving with 12VDC. I paralleled the output of 12 of them through blocking diodes to push a 800 watt array of RGB LED's.

The kind I bought is huge compared to the one you found:

NEW 10A DC DC 600W 10 60V TO 12 80V Boost Converter Power Supply M8 | eBay
 
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rhd

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This post is of no help, but that is the smallest I've seen. I bought some 600W "10A" boost power supplies to push some 100 watt LED's at 38VDC and the most current I could get out of each one was a bit more than 3 amps when driving with 12VDC. I paralleled the output of 12 of them through blocking diodes to push a 800 watt array of RGB LED's.

The kind I bought is huge compared to the one you found:

NEW 10A DC DC 600W 10 60V TO 12 80V Boost Converter Power Supply M8 | eBay

When you got 3A from 12V input, what was the boosted output voltage?

Your board may actually be helpful if the one I ordered is under powered. There's a ton of space that can be eliminated by going two sided, removing the fuse, switching the aluminum caps for ceramic, and removing the terminals and screw holes. I could probably get that board down to 25% its current size. Thanks!
 

sinner

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This looks a lot like Aluminium MCPCB to me.

Easy to drive 65W 90W dual-core notebook.
Main application seems to be a laptop car charger
 
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When driving at 12VDC with the output voltage set to 38 VDC I could only get about 3 amps out, maybe a bit more, 3.5 amps, but not 4 amps. Earlier before buying the 600W unit, I had tried a 100 watt boost to do the same thing and could only get about 1 amp out, maybe less, I don't remember clearly now for that one but I have 10 of them I can't use due to the low current at 38VDC, they are really low power junk: http://www.ebay.com/itm/DC-DC-100W-...-Mobile-Power-Supply-LED-Driver-/181031410566

The higher the boost voltage, the less current they can put out. Roughly, if you triple the voltage, the rated output current is cut to 1/3 out, 4 X the voltage boost 1/4 the current out (actually a bit less due to losses). All of this is elementary to you as a driver designer, my main point is if they rate them for 100 watts, that rating is only good if your input voltage is close to the output voltage, otherwise these run out of steam.
 
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rhd

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When driving at 12VDC with the output voltage set to 38 VDC I could only get about 3 amps out, maybe a bit more, 3.5 amps, but not 4 amps. Earlier before buying the 600W unit, I had tried a 100 watt boost to do the same thing and could only get about 1 amp out, maybe less, I don't remember clearly now for that one but I have 10 of them I can't use due to the low current at 38VDC, they are really low power junk: DC DC 100W Constant Current Boost Step Up Module Mobile Power Supply LED Driver | eBay

The higher the boost voltage, the less current they can put out. Roughly, if you triple the voltage, the rated output current is cut to 1/3 out, 4 X the voltage boost 1/4 the current out (actually a bit less due to losses). All of this is elementary to you as a driver designer, my main point is if they rate them for 100 watts, that rating is only good if your input voltage is close to the output voltage, otherwise these run out of steam.

It may be the case that these drivers are using external MOSFETS (in fact, I suspect it is), so I may be able to use the board I ordered, with a slightly better MOSFET and inductor with higher saturation current, and get more out of it.
 




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