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Re: [Xylo-SDR] RFC - Powers



Phil

I am with you on this one. We don't want our little project to get out of $
control. Also the FPGA board, case, MB would be a good product for Leon or
other entrepreneur to sell for profit, IF we didn't need a $100 dc-dc brick
inside.  Now if we could run a PA off 3.2 V at 25 amps and maintain
linearity this Would be the station supply! 

What ARE our buss powers?. Can we do it with the standard molex 4 pin on the
MB? 

Eric

 

-----Original Message-----
From: xylo-sdr-bounces@lists.ae5k.us [mailto:xylo-sdr-bounces@lists.ae5k.us]
On Behalf Of Phil Harman
Sent: Monday, January 16, 2006 7:15 AM
To: Xylo-SDR Discussion
Subject: Re: [Xylo-SDR] RFC - Powers

All,

At work I've built a number of commercial projects built around PC power 
supplies.  They give +/-12/5/3.3v etc at high currents and are very low cost

and very small.  For  9-15v input you can get  DC to DC PC power supplies 
with the same voltages from Taiwan that are again small, low cost and highly

efficient.

If we base our rear panel power connector on PC power sockets then we have 
1000's of potential power supplies to choose from.  I had one made specially

for me in Taiwan recently and it has low EMC and not much more expensive 
than an off the shelf unit.

For shack use they come free from junked PC's!   My 100w PA uses one that I 
rewound the transformer to give 13.5v @ 20A and it's been working for years.

Phil...VK6APH




----- Original Message ----- 
From: "Eric Ellison" <ecellison@comcast.net>
To: "'Xylo-SDR Discussion'" <xylo-sdr@lists.ae5k.us>
Sent: Monday, January 16, 2006 7:06 PM
Subject: Re: [Xylo-SDR] RFC - Powers


> Guys
>
> Thanks for all the comments re power.
>
> I am in favor of single 11-14 volt input to the back of the radio.
>
> However, I do realize that, due to heat, noise, etc. this might not be
> do-able.
>
> Possibly an external computer power supply? I think all the voltages we
> might need are present except for perhaps the - voltage.
>
> There are quite a few DC-DC converters available, in chip-dip, fractional
> brick etc, but I have not Googled much.
>
> Eric
>
>
> -----Original Message-----
> From: xylo-sdr-bounces@lists.ae5k.us 
> [mailto:xylo-sdr-bounces@lists.ae5k.us]
> On Behalf Of Ahti Aintila
> Sent: Monday, January 16, 2006 2:22 AM
> To: Xylo-SDR Discussion
> Subject: Re: [Xylo-SDR] RFC - Powers
>
> Due to the international electrical safety and electromagnetic
> compatibility regulations (UL, UR, CE, FCC, etc.) I prefer 13.8 V DC and
> a separate UL/CE approved power supply for the 100 - 240 V, 50 - 60 Hz
> wall outlet connections. Only very quiet switching power supplies are
> acceptable, otherwise use bulky linear regulated equipment.
>
> Be extremely careful with shielding and filtering, if you have to use
> switching regulators inside the box. Leon is right, generating the low
> voltage logic power directly with linear regulators from 13.8 V DC
> certainly will heat up the small box too much.
>
> 73, Ahti OH2RZ
>
>
> ----- Original Message ----- 
> From: "KD5NWA" <kd5nwa@cox.net>
> To: "Xylo-SDR Discussion" <xylo-sdr@lists.ae5k.us>
> Sent: Monday, January 16, 2006 2:15 AM
> Subject: Re: [Xylo-SDR] RFC - Powers
>
>
> +5V, +- 13.8V
>
> Three scenarios, #1 is the most practical,  when
> you try to do too many things it cost too much.
>
> Scenario 1
>
> Input power source is either 13.8V or 110V-220V
> power cord, using a switcher to generate all power.
>
> The +5 at 5 to 8 amps, logic power, can be used
> in a card when 3.3V is required.
> The +13.8 2 to 3 amps used with local regulation
> for op-amps. Raw power for a modest amplifier.
> The -13.8 at .5A or less, very little power
> needed, used mostly with op-amps that use +-
> power, local regulated to a lower voltage for noise consideration.
>
> Scenario 2
>
> +13.8 is the input power source, desire to have
> fairly high power out from an amplifier.
>
> The +5 at 5 to 10 amps, logic power, can be used
> in a card when 3.3V is required.
> The +13.8 5 to 10 amps used with local regulation
> for op-amps. Raw power for a amplifier.
> The -13.8 at .5A or less, is derived from the
> +13.8, very little power needed, used mostly with
> op-amps that use +- power, local regulated to a
> lower voltage for noise consideration.
>
> Scenario 3
>
> Power supplied by wall outlet (110V-220V) using a switching power
> supply.
>
> High fidelity audio modes desired, running RF final at 28Volts.
>
> The +5 at 5 to 10 amps, logic power, can be used
> in a card when 3.3V is required.
> The +13.8 5 amps. Used to power op-amps with
> local regulation, raw power for power amplifier.
> The -13.8 at 5 amps ,  very little power needed,
> used for op-amps that use +- power, local
> regulated to a lower voltage for noise
> consideration. Used for power output stage to run
> on 28V for higher efficiency, better quality RF in voice modes.
>
>
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