Re: #ubitx Power Supply For uBitx? #ubitx

Jerry Gaffke

12v at 5A = 60 Watts, more than enough if powering the IRF510 finals from 12v.

If you plan  to someday use that 12v supply to power a boost mode switching power supply 
that generates 24v for the IRF510's, then 5 Amps is marginal, you might want more like 10A.

Perhaps more than you want to know:

UBitx power output at 12v is around 10 Watts, maybe a bit more.
The IRF510's are about 50% efficient, so 20 Watts into the IRF510's, and the rest of the
rig probably needs about 5W.   So will draw around 25 Watts from your 60 Watt supply.

Power out of the IRF510's is proportional to the square of the voltage
there are some losses involved so it really wont' rise that high.
But this means that if you double the voltage to the IRF510's from 12 to 24v,
the power into the IRF510's may rise from 20 Watts to as much as 80 Watts.
Exceeding the capabilities of your 60 Watt 12v supply.
So maybe you need a 10A supply?

It might be possible to get a power supply for free from an old computer.
These often have multiple 12v outputs, each giving 10 or 20 Amps.
There are notes on the web for how to make use of such a beast as a 12v bench supply.
Primary issue is that it may create too much interference for the receiver
without extra filtering.   With some work it may be possible to create a 24v output
by running two 12v ;output windings in series.  This would require cutting one of
those windings free from the power supply's ground reference, and may not be trivial to do.

Be sure to include fuses, perhaps 0.5A into the main uBitx board and a separate fuse
into the IRF510 finals. A 3 Amp fuse should be sufficient if operating the IRF510's from 12v.

On Mon, Jan 15, 2018 at 06:01 pm, Michael Monteith wrote:
My thought is probably a 12v 5A power supply.  

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