Re: [Xylo-SDR] RFC - Powers

[KD5NWA <kd5nwa@cox.net>]

+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.

At 04:03 PM 1/15/2006, you wrote:
> Folks
>  
> Changed the subject in the header. 
>  
> I hope folks like Bill ? KD5TFD, Phil ? VK6APH, Phil ? N8VB are designing
> their projects based on some of the constants we are defining are NOT
> reading all this stuff based on subject. Hopefully they WILL trust that
> we are commenting and deciding and are keeping their project in
> mind.
>  
> What powers do we want coming into the MB?
>  
> Do we want to create a power board within the enclosure or have power
> source external to the enclosure?
>  
> I?ll kick it off.
>  
> I would like to see us use the ?rest? of our 100 x 156 (ID) x 113 mm
> enclosure for a powers board.
> I would like to see a SINGLE 12 volt input to the back of the enclosure
> with other voltages derived from that via DC-DC regulators.
> On project board regulators should use the power supplied from this slide
> in board for component power, from the buss.
>  
> Thoughts for the ?rest of the space? is take +12 Volt input from the back
> of the enclosure to a DC to DC converter to supply:
>  
> +12 V ( passthru from back panel regulated, not highly filtered,
> unlimited current)
> 5 V
> +/- 15 V.
>  
>  
> Comments?
>  
> Eric
>  
>  
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Cecil Bayona
KD5NWA
www.qrpradio.com

"I fail to see why doing the same thing over and over and getting the same results every time is insanity: I've almost proved it isn't; only a few more tests now and I'm sure results will differ this time ... "