30-60V DC power source for arduino... how?

For a project I need to get nice (as in no spikes or outages) 9V to my Arduino. Unfortunately the supplied voltage can range anywhere from 30 - 60 V (there is no way around this).

From what I know so far, I will need a transformator to bring the voltage down, a voltage regulator to stabilize the power to 9V, and a capacitor (the power may be very briefly disconnected).

That's the theory, now in practice... I have no idea what kind of elements I need to buy to accomplish this.

Can anyone with a little more knowledge of electronics point me in the right direction?

Thanks!

the supplied voltage can range anywhere from 30 - 60 V

Is that a DC or AC voltage? If DC, is the voltage 'floating' or is one side terminal grounded. If grounded, is the other terminal voltage a positive or negative voltage?

Also how much current are you going to require for your application, just the normal Arduino board's requirement or are you powering external component loads. If so what will the total current load be?

PS: just noticed you said DC in the posting title, other questions still apply. PS #2: Also what is the current capacity of the 30-50vdc source supply? PS #3: You mentioned "power may be very briefly disconnected". How long at the most may it be disconnected?

Sorry for all the questions, but a good solution requires knowing all the variables involved.

Lefty

DC voltage.

I think the voltage is floating, not entirely sure.

The arduino will power an RFID reader (like this one: http://www.parallax.com/Store/Microcontrollers/BASICStampModules/tabid/134/ProductID/114/Default.aspx?SortField=ProductName%2CProductName)and an XBee module (multi-point, up to 300ft), and also needs to be able to close a relay (the line it needs to close is also 30-60V and up to 8A, I think, not sure).

The reason I'm not sure about certain things is that I need to contact an engineer in italy to know, and it's already past office hours here.

The reason I'm not sure about certain things is that I need to contact an engineer in italy to know

Understood. The quality of the solution is dependent on the specific answers to the questions. I'm sure a simple solution could be offered but rather wait for specific values asked for.

Lefty

Okay, I'll call first thing in the morning.

Thanks for your help!

Unfortunately the supplied voltage can range anywhere from 30 - 60 V (there is no way around this).

This is normal in the telecomm world: the nominal 48V battery backup system can vary across a wide range, depending on whether it's charging or discharging.

When I was working in that area, the engineers built the equipment with what was called a "wide-mouth power supply": a DC-DC converter that tolerates a big range of inputs and produces a stable output. It's pretty much a switching power supply that runs off DC, instead of AC.

You might find something suitable on the surplus market: I think Marlin P. Jones carries some. If not, the usual industrial electronics dealers like Mouser and Digi-key can probably help you (just be sure you're sitting down when you check the prices :o).

(Just for the heck of it, I peeked at MPJA, and they have this unit real cheap. But watch out for "minimum load" requirements: some switchers won't regulate properly if you're not drawing some minimum percentage of their rated output. You definitely don't want 48V going into your Arduino!)

Ran

This chip will accept up to 60V and buck it down to any voltage you need, at 1A: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=LM2591HVT-ADJ-ND

You have to supply a coil, a diode, two capacitors, and some resistors.

The chip alone is $5 so total cost may be $8-$10. It’s possible to build a cheaper DC-DC converter, but it requires a lot more design calculations and hunting down parts.

Is that a DC or AC voltage? If DC, is the voltage 'floating' or is one side terminal grounded. If grounded, is the other terminal voltage a positive or negative voltage?

Also how much current are you going to require for your application, just the normal Arduino board's requirement or are you powering external component loads. If so what will the total current load be?

PS: just noticed you said DC in the posting title, other questions still apply. PS #2: Also what is the current capacity of the 30-50vdc source supply? PS #3: You mentioned "power may be very briefly disconnected". How long at the most may it be disconnected?

Just got an answer back.

Checked with my electrician and he told me negative pole of DC circuit is grounded.

20A at 48V DC is possible normally, could get up to 30/33A if needed. (there will be enough power)

Power can be briefly disconnected. This should take no longer than a second.

Power can be briefly disconnected. This should take no longer than a second.

A second is a long time for a power supply to hold up. This is a function of the output smoothing capacitor size and the current load you are drawing. So you have to be sure of the current drain to ensure you will get the hold up time.

So as it is DC then no transformers will be needed (nor would actually work) it is down to either a liner regulator or a switching regulator. What else besides the arduino board are you wanting to power with this?

Only the arduino chip would have to keep working to ensure Xbee connection.

There is a 48V DC electric motor that is also powered with the original power source, and what I want to do is create a circuit different from that one to power the arduino.

One second is really the maximum, 99% percent of the time it will not be that long. I think more like half a second or less.

NATIONAL SEMICONDUCTOR LM2574HVN-5.0

This is the fixed 5v version of DC-DC converter mentioned above.

Used to power Diecimila Board, work great, this is 500mA max output an DIP8 package.