
Very high current power supply (2012) - mindcrime
http://danyk.cz/proud_en.html
======
taneq
A while ago there was a discussion here
([https://news.ycombinator.com/item?id=20293041](https://news.ycombinator.com/item?id=20293041))
about right-angle bends in PCB traces and why we avoid them. One of the
suggested reasons was that they distribute current poorly and can cause
failures under high current. This video
([https://youtu.be/weJdXaGRJGY](https://youtu.be/weJdXaGRJGY)) from the
article is a great illustration of this in action, giving a literal heat map
of current density.

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ragerino
I recommend looking into so called Super Capacitors or Ultra Capacitors. They
are widely used where a quick and high initial load (power)is required.

AFAIK super capacitors are used for backup power systems and electric car
batteries. I think I hear that Tesla battery packs have super capacitors to
protect those Litium cells from getting damaged during short high load needs.

I am currently planning a small hobby project where I want to build a small
autonomous sensor station using ESP32 and LORA, powered with solar cells using
super capacitors as energy buffer charged through a buck boost converter with
simple MPPT functionality.

A protection circuit in front of you appliance is mandatory since super
capacitors can unleash high loads for a short period of time. I use here a
second buck-boost converter which outputs constantly 3.3 volts for the ESP32
board and sensors.

~~~
nickpsecurity
My favorite use would be rail guns. Cuz they're awesome. :)

[https://www.youtube.com/watch?v=fKEaDhDTciQ](https://www.youtube.com/watch?v=fKEaDhDTciQ)

Some are funnier than they are awesome:

[https://www.youtube.com/watch?v=vAs9EHtKfVc](https://www.youtube.com/watch?v=vAs9EHtKfVc)

~~~
rubidium
I've worked at a much smaller scale then those (12" length), but yes
capacitors are very fun.

I used a screwdriver taped to a meter stick to complete the circuit : )

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snops
Having needed something like this recently, I would recommend utilising
48V-12V convertors designed for servers. Telecoms equipment has long been 48V
(actually -48V) but some datacenters are moving that way too for internal
distribution.

There are some automotive designs for 48-12V conversation, but these are not
really available as modules as automotive is large volume and high
integration. Using discrete components gets expensive fast at these power
levels, a Renesas 2KW reference design I saw needed a 4 layer, 6oz PCB which
would have cost ~$500 to prototype in China.

The Vicor BCM series can do 48V->12V 150A out in a very nice self contained
module, with excellent EMI shielding, and takes cables directly, although
definitely needs a heatsink!
[http://www.vicorpower.com/products?productType=cfg&productKe...](http://www.vicorpower.com/products?productType=cfg&productKey=BCM3814V60E10A5C02)

~~~
H8crilA
What did you need so many amps for? My imagination falls short of melting
things (like OP did).

~~~
Bouncingsoul1
Switchgear testing, for HighVoltage (~110KV++) or MediumVoltage (~10KV to 110)
you usually will test only the secondary side, for LowVoltage (~400V -10KV)you
can test the Breaker with a primary source, these Breakers range from 100A to
5000A.

~~~
rurban
But then you would need IGBT's not MOSFET converters.

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rathel
This guy has a YT channel DiodeGoneWild. If you're into EE or dodgy stuff from
eBay, do check him out. Recently he tore down a modern ATX power supply and
did a very in-depth explanation.

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segfaultbuserr
Interestingly, working with low-voltage, high-current power supply has an
uncommon danger: it won't kill you by giving an electric shock, but you may
suffer from serious injury due to joule heating. You would create a massive
electric cooker if there's any accidental short from power to ground,
especially, don't wear any jewel or ring.

~~~
H8crilA
You mean 12 volts at ~unlimited amps supply ran through my body may heat me up
from the inside? Isn't the human body resistance too high for that, even if
you go below the skin on both ends? At 10 ohm it would be just ~15 watts,
hardly dangerous given that human bodies at rest produce ~100 watts of heat.

Edit: fixed numbers.

~~~
segfaultbuserr
> _You mean 12 volts at ~unlimited amps supply ran through my body may heat me
> up from the inside?_

No. But you'll be injured if you short it with any metallic objects while
touching it, like the wiring, the board, your probe, the ring on your finger,
etc.

~~~
klingonopera
Yep. Imagine a ground plane and a positive +12V pole able to supply infinite
amps.

You can short circuit using your body and you'd probably feel a tingle (your
body resistance is not high, but not too low either). But if the ring you're
wearing on your finger is causing the short circuit, thousands of amps will
flow through it, as it has an ultra-low resistance, and heat it up to
temperatures that will quickly cause burns and whatnot.

If the device does not have infinite amps, then this is the case where
normally the power supply's fuse would blow, and thus the ring would never
heat up and nobody would get hurt.

To summarize: Low-voltage, high-current electricity is indirectly dangerous,
whereas any high voltage electricity is inherently directly dangerous.

~~~
dreamcompiler
> Low-voltage, high-current electricity is indirectly dangerous, whereas any
> high voltage electricity is inherently directly dangerous.

Very high voltage with very low current is not inherently dangerous. Static
electricity is this case. The total energy (voltage x current x time) passing
through the body is the critical determinant of harm.

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cr0sh
These are very strangely drawn circuits, particularly the power supply that
powers this power supply; in that one, the circuit seems to almost be drawn
right to left, at least for the low-voltage portion (which is tapped off the
high voltage portion if I read things right).

This strangeness is probably - in all likelyhood - due to regional differences
(east vs west schematic "standards"), plus the fact that we are dealing with
power supplies, which are always messy and strange for non-trivial
implementations.

Also something to keep in mind here - for the 60 volt power supply that powers
this high-current supply, the AC input is 230 VAC, likely at 50 Hz (ie -
European AC power standard). The circuit as-is likely won't work or will work
poorly, without being redesigned for the US standard wall-power (120 VAC, 60
Hz) - or even if you use the higher US standard (220-240 VAC, 60 Hz).

Just something to keep in mind - that basically the initial input stage to the
first power supply will need to be altered (and perhaps that weird low-voltage
supply tap, too); everything after that will probably be OK, since it is DC
after that point (albeit 300+ volt DC - so be careful!).

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unnouinceput
Having created for my personal use low voltage/high amperage transformers
myself to use for house repairs when need it and already knowing the danger of
using too much voltage with hundreds of amperes (where the total power would
rise well above 1.5kW) I wonder about this circuitry long term usability. I
know from personal experience that melting metal using such a transformer is
generating a lot of heat that goes back to your transformer isolation. And my
transformer would be 1.75 V in secondary or as high I ever went was 2.25
volts. So reading this diagram that has hundreds of amperes at 12V seems
highly unlikely. That would be over 2kW easily and using this more then 1
minute would definitely destroy the transformer at least. I use my
transformers for maximum 5 minutes then I let them cool for 30 minutes on the
cold concrete.

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sephamorr
This appears to just be a 60v->12v isolated converter at ~2kW. I've never seen
a push-pull topology used for this power level since it makes such inefficient
use of the transformer and FETs (note it uses 4 parallel FETs for each branch
of the primary). Looks fun though

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TD-Linux
Interesting design, though I think if isolation isn't needed, you would do
much better with just a buck topology - half the fets, and no output diodes.
Or a surplus supply as other comments mention.

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jesperhh
Damn, he is doing some crazy stuff - take a look at the x-ray experiments:
[http://danyk.cz/rtg_en.html](http://danyk.cz/rtg_en.html)

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dTal
Some of those videos seem a mite unsafe. What's the purpose of surrounding a
white-hot piece of metal with highly flammable paper? It combusted on two
occasions that we see. The he just removes the paper, and you realize that all
that radiant heat is now hitting the worktop and circuitry...

~~~
phoe-krk
> What's the purpose of surrounding a white-hot piece of metal with highly
> flammable paper?

He likely wanted a nice white background for his video. But, well, it
backfired.

