Old 10-27-2009, 08:24 PM #1
pullbangdead's Avatar
Class 3R Laser
 
Join Date: Aug 2007
Posts: 2,045
Rep Power: 788
pullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond repute
pullbangdead pullbangdead is offline
Class 3R Laser
pullbangdead's Avatar
 
Join Date: Aug 2007
Posts: 2,045
Rep Power: 788
pullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond repute
Default Quick and Dirty High V Boost Driver

Alright, so I know there are people working on various higher-voltage boost drivers, especially with the 8x and 12x Blu-ray diodes in mind.

But I need a quick and dirty solution to get higher voltage output from a boost driver with adjustable constant current drive mode. Doesn't need to be small, or fancy, or elegant, or efficient for the time being. Ideally, at some point in the near future, I'll have time to work on a switching regulator or someone else will come out with a pre-made driver that can do higher voltages, but for the time-being I need something quick and easy.

So like I mentioned, I need the variable current control mode also. So, would I be able to, say build an LM317 driver in constant-current mode like everyone does now, and instead of putting Vin as the battery voltage, throw a single IC or VERY simple circuit that I can grab at Radio Shack tonight on the input side and kick the input voltage up to, say, 20V? Is there some easy way to take the 7.2V output from 2 rechargeable lithiums, kick it up to 20V or so, and feed that higher voltage to an LM317, which will then regulate my current nicely while supplying anywhere from 10 to 18 or so V to the diode?

Seems there should be some very simple circuit that could accomplish this, to feed the LM317 a higher voltage than the batteries allow?

Anyone have a very simple idea like this?

I figure this is easier than doing all the legwork to get a switching regulator working perfectly with clean current control on the output, it seems from my initial searching that getting such a thing working properly would take me a lot longer than just finding a way to bump the Vin to an LM317 up to a higher V. All that, and I'm just an idiot with circuits too.



Last edited by pullbangdead; 10-27-2009 at 08:30 PM.
pullbangdead is offline   Reply With Quote


















Old 10-29-2009, 06:20 AM #2
Bionic-Badger's Avatar
Class 4 Laser
 
Join Date: Oct 2007
Location: Oregon, USA
Posts: 5,478
Rep Power: 18104
Bionic-Badger has a reputation beyond reputeBionic-Badger has a reputation beyond reputeBionic-Badger has a reputation beyond reputeBionic-Badger has a reputation beyond reputeBionic-Badger has a reputation beyond reputeBionic-Badger has a reputation beyond reputeBionic-Badger has a reputation beyond reputeBionic-Badger has a reputation beyond reputeBionic-Badger has a reputation beyond reputeBionic-Badger has a reputation beyond reputeBionic-Badger has a reputation beyond repute
Bionic-Badger Bionic-Badger is offline
Class 4 Laser
Bionic-Badger's Avatar
 
Join Date: Oct 2007
Location: Oregon, USA
Posts: 5,478
Rep Power: 18104
Bionic-Badger has a reputation beyond reputeBionic-Badger has a reputation beyond reputeBionic-Badger has a reputation beyond reputeBionic-Badger has a reputation beyond reputeBionic-Badger has a reputation beyond reputeBionic-Badger has a reputation beyond reputeBionic-Badger has a reputation beyond reputeBionic-Badger has a reputation beyond reputeBionic-Badger has a reputation beyond reputeBionic-Badger has a reputation beyond reputeBionic-Badger has a reputation beyond repute
Default Re: Quick and Dirty High V Boost Driver

If you can find the parts, you can build something like this. Radio shack usually has a pretty shoddy collection of parts though, so good luck with that.

I would instead look at something like rectifying (another) AC power into DC and then using a regulator on that. That only requires some rectifier diodes and a transformer, and even then you can get by without a transformer if you're okay with a full 120V. If you have a crappy ol' LED light bulb from DX it should contain enough components to build one directly. Just watch out, since it's AC.

If you rectify the AC the output is not going to be clean at all. I'm not sure how well the regulator can handle this, but you could put a capacitor before it to try and smooth out the signal a bit.
Bionic-Badger is offline   Reply With Quote
Old 10-31-2009, 12:52 AM #3
charliebruce's Avatar
Class 3R Laser
 
Join Date: Nov 2008
Location: London, UK
Posts: 1,550
Rep Power: 124
charliebruce has a reputation beyond reputecharliebruce has a reputation beyond reputecharliebruce has a reputation beyond reputecharliebruce has a reputation beyond reputecharliebruce has a reputation beyond reputecharliebruce has a reputation beyond reputecharliebruce has a reputation beyond reputecharliebruce has a reputation beyond reputecharliebruce has a reputation beyond reputecharliebruce has a reputation beyond reputecharliebruce has a reputation beyond repute
Send a message via MSN to charliebruce
charliebruce charliebruce is offline
Class 3R Laser
charliebruce's Avatar
 
Join Date: Nov 2008
Location: London, UK
Posts: 1,550
Rep Power: 124
charliebruce has a reputation beyond reputecharliebruce has a reputation beyond reputecharliebruce has a reputation beyond reputecharliebruce has a reputation beyond reputecharliebruce has a reputation beyond reputecharliebruce has a reputation beyond reputecharliebruce has a reputation beyond reputecharliebruce has a reputation beyond reputecharliebruce has a reputation beyond reputecharliebruce has a reputation beyond reputecharliebruce has a reputation beyond repute
Send a message via MSN to charliebruce
Default Re: Quick and Dirty High V Boost Driver

I remember seeing discussion about this before, but the primary reason against this is that the efficiency will be incredibly low - whilst a good buck-boost driver could hit 85-90% on a good day, I doubt that a circuit built along these lines would be able to hit more than 10-30% efficiency. Plus, it wouldn't be as compact either, it would make just as much sense to design a boost driver with heavy-duty components which are able to take the strain of the higher currents - if you look on Linear's site, there are several "power system" designers, where you specify input and output ranges, and it does most of the work for you.
charliebruce is offline   Reply With Quote
Old 10-31-2009, 01:20 AM #4
pullbangdead's Avatar
Class 3R Laser
 
Join Date: Aug 2007
Posts: 2,045
Rep Power: 788
pullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond repute
pullbangdead pullbangdead is offline
Class 3R Laser
pullbangdead's Avatar
 
Join Date: Aug 2007
Posts: 2,045
Rep Power: 788
pullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond reputepullbangdead has a reputation beyond repute
Default Re: Quick and Dirty High V Boost Driver

K.

Yeah, I don't care about efficiency at this point, I just wanted something quick that I could throw together this weekend, without having to order parts. Just something I could put together quickly and throw in a project box, size and efficiency be damned. If I can't get something fast, then I might as well put it off and design a circuit that works well, like a good switching boost drivers.

But it turns out some of the other parts aren't ready yet this week either, so oh well. Looks like it'll be January for this project.
pullbangdead is offline   Reply With Quote
Old 10-31-2009, 02:34 AM #5
pseudolobster's Avatar
Class 3R Laser
 
Join Date: Jan 2008
Location: BC, Canada
Posts: 1,734
Rep Power: 487
pseudolobster has a reputation beyond reputepseudolobster has a reputation beyond reputepseudolobster has a reputation beyond reputepseudolobster has a reputation beyond reputepseudolobster has a reputation beyond reputepseudolobster has a reputation beyond reputepseudolobster has a reputation beyond reputepseudolobster has a reputation beyond reputepseudolobster has a reputation beyond reputepseudolobster has a reputation beyond reputepseudolobster has a reputation beyond repute
pseudolobster pseudolobster is offline
Class 3R Laser
pseudolobster's Avatar
 
Join Date: Jan 2008
Location: BC, Canada
Posts: 1,734
Rep Power: 487
pseudolobster has a reputation beyond reputepseudolobster has a reputation beyond reputepseudolobster has a reputation beyond reputepseudolobster has a reputation beyond reputepseudolobster has a reputation beyond reputepseudolobster has a reputation beyond reputepseudolobster has a reputation beyond reputepseudolobster has a reputation beyond reputepseudolobster has a reputation beyond reputepseudolobster has a reputation beyond reputepseudolobster has a reputation beyond repute
Default Re: Quick and Dirty High V Boost Driver

How about a joule thief?
Make a Joule thief.

If there's a simpler or cheaper boost driver out there, it'd be news to me.
__________________
Custom Text
pseudolobster is offline   Reply With Quote
Reply





Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

























Privacy Policy | Advertising Disclaimer | Terms of Use


 


All times are GMT. The time now is 10:31 PM.


Powered by: vBulletin
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO
Privacy Policy | Advertising Disclaimer | Terms of Use
Copyright (C) 2017 Laser Pointer Forums, LLC