High-power voltage doubler? - Page 1
Forum section: electronics / beginners

author: ok_cool
author_rank: Contributor
timestamp: May 12, 2015, 03:19:14 pm
content: What am I doing wrong when I cannot get such thing to work? Is it simply not possible?I need to step 12 volts up to 24 volts but my simulation simply doesn't work (yield the results I expect it to) when I run it with high loads and MOSFETs.So is it even possible to get it done? Like amps and amps of current.

author: PSR B1257
author_rank: Frequent Contributor
timestamp: May 12, 2015, 03:33:58 pm
content: QuoteAC or DC?QuoteIt would be good to see the circuitQuoteDefineamps.

author: ok_cool
author_rank: Contributor
timestamp: May 12, 2015, 03:55:27 pm
content: 12A DC

author: ok_cool
author_rank: Contributor
timestamp: May 12, 2015, 04:02:04 pm
content: But I mean, I only need the knowledge if it can be done. Like, if I can boost 12V to 24V at ONE MILLION amps.Or if there is something that literally fucks it up.

author: PSR B1257
author_rank: Frequent Contributor
timestamp: May 12, 2015, 04:11:37 pm
content: QuoteNo, all a matter of money

author: ok_cool
author_rank: Contributor
timestamp: May 12, 2015, 04:37:58 pm
content: Quote from: PSR B1257 on May 12, 2015, 04:11:37 pmGod damn man, now I have to figure it out on my own

author: PSR B1257
author_rank: Frequent Contributor
timestamp: May 12, 2015, 04:46:21 pm
content: If you come up with a meaningful (or at least reasonable specified) question, you maybe get a meaningful answer.

author: ok_cool
author_rank: Contributor
timestamp: May 12, 2015, 05:19:13 pm
content: Too bad, I only want intelligent answers. If you know anything about anything you should probably be able to understand what I am after.

author: PSR B1257
author_rank: Frequent Contributor
timestamp: May 12, 2015, 05:24:24 pm
content: Am I a clairvoyant, I don't think so.

author: ok_cool
author_rank: Contributor
timestamp: May 12, 2015, 05:28:03 pm
content: Quote from: PSR B1257 on May 12, 2015, 05:24:24 pmThat's a beautiful word.

author: Sebastian
author_rank: Regular Contributor
timestamp: May 12, 2015, 06:27:03 pm
content: Quote from: ok_cool on May 12, 2015, 03:19:14 pmWhat you need is a switched mode converter. Boost topology in your case.What you are probably trying to use is a charge pump circuit, which is very uncommonly, or never, used for higher currents than a few hundred milliamps. (At least I can't think of any application where that would be useful.)

author: Neilm
author_rank: Super Contributor
timestamp: May 12, 2015, 06:33:36 pm
content: Quote from: Sebastian on May 12, 2015, 06:27:03 pmCould also use a flyback circuit or resonant circuit - I have used both for step up applications which needed high voltage isolation.One simple thing to try would be changing a couple of components - for instance I have had issues with some of the FETs in LTSpice not working correctly. Changing to another FET makes the simulation run.

author: Sebastian
author_rank: Regular Contributor
timestamp: May 12, 2015, 06:38:39 pm
content: Quote from: Neilm on May 12, 2015, 06:33:36 pmYep, of course there are topologies like flyback with isolated secondary side if you need that. Boost is just the simplest one.

author: ok_cool
author_rank: Contributor
timestamp: May 15, 2015, 05:26:17 pm
content: Quote from: Sebastian on May 12, 2015, 06:27:03 pmYeah that was my original design. 5 LTC1624 each boosting 12V to 33V at 3A each. But if I got my calculations correct the peak inductor current would be larger than my 6A inductors so it might require larger and more expensive inductors, so I thought maybe it would be possible to first use voltage doubler to do 12V to 24V and then boost it to 33V.

author: ConKbot
author_rank: Super Contributor
timestamp: May 15, 2015, 10:36:04 pm
content: No schmatic, just "simulation doesnt work, why?"Sure, you can build a voltage doubler that can handle a few A. Big enough capacitors, big enough switching mosfets, and you're in business.

author: Delta
author_rank: Super Contributor
timestamp: May 16, 2015, 11:40:50 am
content: If your simulator is running on a PC with a standard ATX PSU, then the maximum voltage it can produce is 12v.

author: Psi
author_rank: Super Contributor
timestamp: May 16, 2015, 12:28:59 pm
content: Quote from: ok_cool on May 12, 2015, 04:02:04 pmyou would need liquid helium cooled superconductors to carry voltage that low with that current and not lose everything in the wiring.

author: max_torque
author_rank: Super Contributor
timestamp: May 16, 2015, 12:42:52 pm
content: Quote from: ok_cool on May 15, 2015, 05:26:17 pmIt's "possible" to do pretty much anything, given enough money & Time.However, (as far as we understand today) the lawd of basic physics cannot be changed #startrekSo, no matter how many stages you use, increasing 12V to 33V is still a step up of 21V.The efficiency of such a step up is broadly speaking determined by the resistive losses in the path across which the current flows. ie, the mosfets, inductors, capacitors etc in the circuit.You may choose to do this power conversion in one step, or multiple parallel paths (21Vdc increase, but lower current per path, to limit the size of components, and bringing the advantages of a multiphase architecture to bear etc), or multiple series paths (ie a lower voltage step per stage, but each at full current).Regardless, this doesn't somehow magically improve efficiency or make it easier to do.Think about trying to lift 1 ton of rocks up to the 3rd floor of a building. You could pay lots of people to each take 1 rock up, or pay a lesser number of stronger people to carry say 10 up at once. In either case the work done is the same. And although starting with those rocks already on the 3rd floor means they don't have to be lifted as far to reach the 3rd floor, how did they get to the 2nd floor in the first place?

author: mzzj
author_rank: Super Contributor
timestamp: May 16, 2015, 03:45:51 pm
content: Quote from: Psi on May 16, 2015, 12:28:59 pm24000 pcs of 1kW switcher modules wired in parallei, 25mm2 cable to each module, busbars with 600000 mm2 = 0,6m2cross section should do.