Forum: GNU Radio Mobile Power Supply for USRP

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Eric A. Cottrell (Guest)
on 2007-05-06 19:00
(Received via mailing list)
Hello,

Is there a off-the-shelf product to power the USRP from 13.8 volts?  My
understanding is the USRP needs a couple of amperes at 6 volts.  The
best I saw was 1 Ampere maximum output.

73 Eric
Daniel O'Connor (Guest)
on 2007-05-07 04:41
(Received via mailing list)
On Monday 07 May 2007 00:29, Eric A. Cottrell wrote:
> Is there a off-the-shelf product to power the USRP from 13.8 volts?
> My understanding is the USRP needs a couple of amperes at 6 volts.
> The best I saw was 1 Ampere maximum output.

I think you could use DC-DC converter that outputs 5V.

The dropout on the regulator used is 1.5V, and 3.3 + 1.5 = 4.8V. Not a
lot of headroom but it should work OK.. Right? :)

You could test it using your PC power supply before spending money too.

Farnell sell DC/DC converters that will do the job but they are not
cheap (>AU$100)
http://au.farnell.com/jsp/Electrical/Power+Supplie...

They also sell DC/DC converters that will go down to 3.3V but then you
would need to remove the existing regulator and it would almost
certainly be much noisier without the linear regulator in there.
Matt E. (Guest)
on 2007-05-07 05:55
(Received via mailing list)
Most of the daughterboards regulate the 6V down to 5V, so you really
need about 5.5 to 5.75 V to operate correctly.

Matt
Daniel O'Connor (Guest)
on 2007-05-07 06:15
(Received via mailing list)
On Monday 07 May 2007 11:24, Matt E. wrote:
> Most of the daughterboards regulate the 6V down to 5V, so you really
> need about 5.5 to 5.75 V to operate correctly.

Ah right, I didn't realise they powered off the "before" section of the
regulator.

Going straight to 3.3V would be suboptimal for noise anyway and probably
not save you that much.
Daniel O'Connor (Guest)
on 2007-05-08 07:41
(Received via mailing list)
On Monday 07 May 2007 10:09, Daniel O'Connor wrote:
> They also sell DC/DC converters that will go down to 3.3V but then
> you would need to remove the existing regulator and it would almost
> certainly be much noisier without the linear regulator in there.

Or you could try finding something like this..
http://www.morex.com.tw/products/productdetail.php?fd_id=62

A retailer .au gets them, and I think you'd be able to find someone who
imports it in the US easily enough.
Greg T. (Guest)
on 2007-05-09 19:47
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Charles S. (Guest)
on 2007-05-10 03:27
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On Sun, 2007-05-06 at 10:59 -0400, Eric A. Cottrell wrote:
> Hello,
>
> Is there a off-the-shelf product to power the USRP from 13.8 volts?  My
> understanding is the USRP needs a couple of amperes at 6 volts.  The
> best I saw was 1 Ampere maximum output.
>

There's these from Jameco, YM12S05:

<http://www.jameco.com/webapp/wcs/stores/servlet/Pr...

9.6 to 14V in, 5.5V at 5A out. I was worried about the ripple in the
output (see data sheets) but has not been a problem.

Just needs one small resistor to set output voltage (1.2k for 5.5v)

http://musicriver.homeunix.com:8737/usrp_dcps_1.jpg

--Chuck
Daniel O'Connor (Guest)
on 2007-05-10 04:05
(Received via mailing list)
On Thursday 10 May 2007 08:56, Charles S. wrote:
> 9.6 to 14V in, 5.5V at 5A out. I was worried about the ripple in the
> output (see data sheets) but has not been a problem.

I think that even if there is the input filtering and regulator should
cope with it. Or if not it should be re-designed ;)
Eric A. Cottrell (Guest)
on 2007-05-14 21:36
(Received via mailing list)
Hello,

I went to the local electronics store and got a 2 Ampere Car Adapter.
http://www.velleman.be/fr/en/product/view/?id=350662

I tried it last night and it seems to work.  I was able to use the USRP
in the car with my laptop.

I may get something bigger at Dayton since I have a number of mobile
devices that need 6 volts.

73 Eric
hanwen (Guest)
on 2007-05-15 07:03
(Received via mailing list)
Wether it's OK to pluged the AC-to-DC converter atatched with USRP
directly
on a UPS?

2007/5/15, Eric A. Cottrell <removed_email_address@domain.invalid>:
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