switching power supply for +48?

[substitute]

I don't really know the difference between linear and switching supplies, would something like this work for phantom?

http://www.mouser.com/ProductDetail/Phihong/PSA065-480-R/?qs=sGAEpiMZZMvsF1bnc1hVLfglykq6I224d9fsKRv%2f4gI%3d

 

[ruffrecords]

Yes, except it is far, far too powerful and as a result most likely far too noisy for use as a phantom power supply. The one you linked to will provide an output current of 1.65 amps and rarely will you need more than 0.1 amp.

Switch mode power supplies can be used for phantom power - the Neve phantom power supply of 40 years ago was a simple SMPSU operating from the main +24V supply.

Cheers

Ian

 

[JohnRoberts]

You can calculate the worst case current draw (shorted inputs) at around 14 mA per input, most large consoles ASSume that every input won't get shorted at the same time, so budget a fraction of the 14 mA worst case per.

The Peavey Mark VIII (live sound) console used a switching supply for 48V, conventional rails for all else. 

I have rolled my own high frequency charge pump (variant on cap doubler/tripler), but driven from the main switching frequency used inside a switching supply for the low voltage regular rails, instead of doubling at the mains frequency. This was adequate for a small one mic input DSP, using tiny cap values.

JR

 

[PRR]

> it is far, far too powerful

OTOH, it is only $24.

For that price he can put 2 ohms and 1,000uFd on it to clean the HF crap.

And seems to be the only 48V supply Mouser has in-stock today (12 units).

 

[substitute]

> it is far, far too powerful

OTOH, it is only $24.

For that price he can put 2 ohms and 1,000uFd on it to clean the HF crap.

And seems to be the only 48V supply Mouser has in-stock today (12 units).

That's really where I was coming from, I know it's way more juice than I need, if mouser had something smaller I'd go with that, I wanted to keep my parts order down to one vendor.  I didn't know that excess available current would lead to noise though so thanks for pointing that out. 

I have rolled my own high frequency charge pump (variant on cap doubler/tripler), but driven from the main switching frequency used inside a switching supply for the low voltage regular rails, instead of doubling at the mains frequency. This was adequate for a small one mic input DSP, using tiny cap values.

Normally I'd probably do something like that, this is for a rack job for some friends (i.e. free of charge) so my goal is to keep it really simple.

Thanks for the insights everyone

 

[Jean Clochet]

If you can deal with Digikey, there's a smaller one for a bit less $ here:

http://search.digikey.com/scripts/DkSearch/dksus.dll?x=13&y=10&lang=en&site=us&KeyWords=102-2043-ND

It's always a good idea to filter the output from a SMPS anyway, regardless of size, so PRR's suggestion of a small R with a big cap still holds. 

 

[substitute]

That's a cool option, digikey not so much. 

It's funny the web developer I work for was pitching them last year, they had no interest in a new site.

 

[peterc]

Could try one of these:

http://www.nomad.ee/micros/mc34063a/

 

[ruffrecords]

> it is far, far too powerful

OTOH, it is only $24.

For that price he can put 2 ohms and 1,000uFd on it to clean the HF crap.

Except 99.99% of all cheap  SMPSU specify that you must not load them with a significant capacitance.

Cheers

Ian

 

[MagnetoSound]

Igor designed a great little add-on switcher, the UniPhan. I don't know how far along he is with production but it seems like a tidy solution if you already have a positive audio rail available. 

 

[substitute]

Except 99.99% of all cheap  SMPSU specify that you must not load them with a significant capacitance.

I didn't see this mentioned in the data sheet, doesn't mean it wouldn't be a problem though.  What would go wrong if this were the case?

Could try one of these:

http://www.nomad.ee/micros/mc34063a/

Nice calculator, but the mc34063 is $62 at mouser.

In this particular instance I decided that the best solution is the JLM +48v supply and go betweens.  Those things get a little pricy, but since I'm doing this as a favor I figure they can pay a bit extra to make it easier for me. 

 

[peterc]

the mc34063 is $62 at mouser

Ok! At my local electronics store they are under a dollar! 

Try this one:

http://za.mouser.com/ProductDetail/ON-Semiconductor/MC34063AP1G/?qs=sGAEpiMZZMtqO%252bWUGLBzeCl00v6tT3KJ

Peter

 

[gemini86]

try 63 cents...

http://www.mouser.com/ProductDetail/STMicroelectronics/MC34063ACN/?qs=sGAEpiMZZMu%252byDKIQBKlyfr1rQzq2Atyi9gSZl0WP10%3d

don't by the eval board, the datasheets contain pcb etch artwork to make your own...

 

[substitute]

Ooooooohhhhhh, I get it.  I searched "MC34063A" and saw these...

http://www.mouser.com/Search/Refine.aspx?Keyword=MC34063A

That's actually really cool Peter!

try 63 cents...

http://www.mouser.com/ProductDetail/STMicroelectronics/MC34063ACN/?qs=sGAEpiMZZMu%252byDKIQBKlyfr1rQzq2Atyi9gSZl0WP10%3d

don't by the eval board, the datasheets contain pcb etch artwork to make your own...

Very cool

What's the "L" inductor about?

 

[gemini86]

check out the following image.

The controller turns the MOSFET on and dumps your low voltage through the inductor to ground, saturating it. Then when the controller turns the MOSFET off, the stored energy in the inductor must go through the diode (D1) and charge C5 with whatever voltage spike it outputs. It does this repeatedly until the voltage on the output is high enough to cause 1.25 volts on pin 5 of the controller which is fed by a voltage divider (R3, P1, R1) hanging off the HV output. The output could be set up for whatever.. 24v, 48v, 400v... The inductor should be able to pass about 2A to be safe, and about 220uH should do it (although I used a 100uH part from radioshack with success). Shielded will be better for audio use, but an unshielded inductor will give higher efficiency, if that's something you're worried about at all.

 

[e.oelberg]

this is a good place for PSUs, theey are not cheap but dead quiet, check the specs...all german though
http://funk-tonstudiotechnik.de/NETZTEILE.htm