5volt power supply
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Posts: 46,084
It is quite fashionable to use a 7805 regulator to provide 5 volt power from
a 12 volt power source (read car battery). Because of the large voltage gap
between the car battery and the 5 volt output, considerable power is wasted
as heat. The major advantages of using the 7805 are simplicity and cost. A
power supply can be built on a tiny board at a very low cost. However, the
heat becomes a problem, especially at somewhat high (300-400ma) power
levels.
I am looking for a way to build a power supply on a relatively small board
at a reasonable cost that could avoid, or at least minimize this thermal
problem. Suggestions would be appreciated as would a CC reply to my e-mail
address.
TIA
Vic
________________________________________________________
Victor Fraenckel - The Windman vfraenc1@n...
KC2GUI www.windsway.com
Home of the WindReader Electronic Theodolite
Read the WIND
a 12 volt power source (read car battery). Because of the large voltage gap
between the car battery and the 5 volt output, considerable power is wasted
as heat. The major advantages of using the 7805 are simplicity and cost. A
power supply can be built on a tiny board at a very low cost. However, the
heat becomes a problem, especially at somewhat high (300-400ma) power
levels.
I am looking for a way to build a power supply on a relatively small board
at a reasonable cost that could avoid, or at least minimize this thermal
problem. Suggestions would be appreciated as would a CC reply to my e-mail
address.
TIA
Vic
________________________________________________________
Victor Fraenckel - The Windman vfraenc1@n...
KC2GUI www.windsway.com
Home of the WindReader Electronic Theodolite
Read the WIND
Comments
also help to share the heat.
To improve efficiency a switching DC-DC converter is the choice.
There are many manufacturers of isolated or non isolated modules with
reasonable prices. PowerTrends have 78xx similar regulators but
switchers. Now company was purchased by Texas and was difficult to me to
locate a specificic module.
ACJacques
Vic Fraenckel wrote:
>
> It is quite fashionable to use a 7805 regulator to provide 5 volt power from
> a 12 volt power source (read car battery). Because of the large voltage gap
> between the car battery and the 5 volt output, considerable power is wasted
> as heat. The major advantages of using the 7805 are simplicity and cost. A
> power supply can be built on a tiny board at a very low cost. However, the
> heat becomes a problem, especially at somewhat high (300-400ma) power
> levels.
>
> I am looking for a way to build a power supply on a relatively small board
> at a reasonable cost that could avoid, or at least minimize this thermal
> problem. Suggestions would be appreciated as would a CC reply to my e-mail
> address.
>
> TIA
>
> Vic
>
> ________________________________________________________
>
> Victor Fraenckel - The Windman vfraenc1@n...
> KC2GUI www.windsway.com
>
> Home of the WindReader Electronic Theodolite
> Read the WIND
Power Trends makes little switcher modules that work very well. A bit
pricey, but very cool and most require no external components (some require
an external cap). A little more noise on the output compared to a 7805 as
you might expect.
I've used them. They have been hard to get but now that TI bought them,
maybe that'll let up some.
Look up Power Trends on DigiKey's site or http://www.powertrends.com/
Regards,
Al Williams
AWC
* New! 20MHz PAK-I does math twice as fast -- act now and save $5.
http://www.al-williams.com/awce/pak1.htm
>
Original Message
> From: Vic Fraenckel [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=5xGemllg4ehqlQbhgE6ia4LZ0QGrryJcAk7qAbtonMJclw1sT6rFz35sEOZnToIFjtoIthgptC3aH4qNGDtIHg]vfraenc1@n...[/url
> Sent: Sunday, December 03, 2000 5:12 AM
> To: Stamp Mailing List
> Subject: [noparse][[/noparse]basicstamps] 5volt power supply
>
>
> It is quite fashionable to use a 7805 regulator to provide 5 volt
> power from
> a 12 volt power source (read car battery). Because of the large
> voltage gap
> between the car battery and the 5 volt output, considerable power
> is wasted
> as heat. The major advantages of using the 7805 are simplicity and cost. A
> power supply can be built on a tiny board at a very low cost. However, the
> heat becomes a problem, especially at somewhat high (300-400ma) power
> levels.
>
> I am looking for a way to build a power supply on a relatively small board
> at a reasonable cost that could avoid, or at least minimize this thermal
> problem. Suggestions would be appreciated as would a CC reply to my e-mail
> address.
>
> TIA
>
> Vic
>
> ________________________________________________________
>
> Victor Fraenckel - The Windman vfraenc1@n...
> KC2GUI
> www.windsway.com
>
> Home of the WindReader Electronic Theodolite
> Read the WIND
>
>
>
>
Switchers are the elegant (and expensive)
solution, but first take
a good look at your loads. What is taking most of
the current?
If it is relays or indicators(lamps, LEDs, etc.),
most of these can
be made to work from the 12v itself, thus
bypassing the regulator.
Just a thought.
--Stu
Original Message
From: Vic Fraenckel <vfraenc1@n...>
To: Stamp Mailing List <basicstamps@egroups.com>
Sent: Sunday, December 03, 2000 3:11 AM
Subject: [noparse][[/noparse]basicstamps] 5volt power supply
> It is quite fashionable to use a 7805 regulator
to provide 5 volt power from
> a 12 volt power source (read car battery).
Because of the large voltage gap
> between the car battery and the 5 volt output,
considerable power is wasted
> as heat. The major advantages of using the 7805
are simplicity and cost. A
> power supply can be built on a tiny board at a
very low cost. However, the
> heat becomes a problem, especially at somewhat
high (300-400ma) power
> levels.
>
> I am looking for a way to build a power supply
on a relatively small board
> at a reasonable cost that could avoid, or at
least minimize this thermal
> problem. Suggestions would be appreciated as
would a CC reply to my e-mail
> address.
>
> TIA
>
> Vic
>
>
__________________________________________________
______
>
> Victor Fraenckel - The Windman
vfraenc1@n...
> KC2GUI
www.windsway.com
>
> Home of the WindReader Electronic
Theodolite
> Read the WIND
>
>
>
>
>
>
>It is quite fashionable to use a 7805 regulator to provide 5 volt power from
>a 12 volt power source (read car battery). Because of the large voltage gap
>between the car battery and the 5 volt output, considerable power is wasted
>as heat. The major advantages of using the 7805 are simplicity and cost. A
>power supply can be built on a tiny board at a very low cost. However, the
>heat becomes a problem, especially at somewhat high (300-400ma) power
>levels.
>
>I am looking for a way to build a power supply on a relatively small board
>at a reasonable cost that could avoid, or at least minimize this thermal
>problem. Suggestions would be appreciated as would a CC reply to my e-mail
>address.
National Semiconductor simple switcher series - you can build a 5V 1A power
supply on a 1" square board.
dwayne
Dwayne Reid <dwayner@p...>
Trinity Electronics Systems Ltd Edmonton, AB, CANADA
(780) 489-3199 voice (780) 487-6397 fax
Celebrating 16 years of Engineering Innovation (1984 - 2000)
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Do NOT send unsolicited commercial email to this email address.
This message neither grants consent to receive unsolicited
commercial email nor is intended to solicit commercial email.
Marlin P. Jones has a neat switcher for $15. You can't build it for that
price. It may be larger than you want, about 3"x5"x1.25".
10-20V in
OUTPUTS:
+5V @2a
+12V @ 0.1a
-12V @ 0.125a
+20V @ 0.02a
stock #12588
www.mpja.com
Ray McArthur
Original Message
From: Vic Fraenckel <vfraenc1@n...>
To: Stamp Mailing List <basicstamps@egroups.com>
Sent: Sunday, December 03, 2000 6:11 AM
Subject: [noparse][[/noparse]basicstamps] 5volt power supply
> It is quite fashionable to use a 7805 regulator to provide 5 volt power
from
> a 12 volt power source (read car battery). Because of the large voltage
gap
> between the car battery and the 5 volt output, considerable power is
wasted
> as heat. The major advantages of using the 7805 are simplicity and cost. A
> power supply can be built on a tiny board at a very low cost. However, the
> heat becomes a problem, especially at somewhat high (300-400ma) power
> levels.
>
> I am looking for a way to build a power supply on a relatively small board
> at a reasonable cost that could avoid, or at least minimize this thermal
> problem. Suggestions would be appreciated as would a CC reply to my e-mail
^Try to find a 78SR05,
This is a switchmode regulator that have all components inside.
it's just a little bigger than a 7805 .
and the powerdisipation (heat) is gone.
Best regards , Cees.
Original Message
From: "Ray McArthur" <rjmca@u...>
To: <basicstamps@egroups.com>
Cc: <vfraenc1@n...>
Sent: Sunday, December 03, 2000 10:56 PM
Subject: Re: [noparse][[/noparse]basicstamps] 5volt power supply
> Vic:
> Marlin P. Jones has a neat switcher for $15. You can't build it for that
> price. It may be larger than you want, about 3"x5"x1.25".
>
> 10-20V in
> OUTPUTS:
> +5V @2a
> +12V @ 0.1a
> -12V @ 0.125a
> +20V @ 0.02a
>
> stock #12588
> www.mpja.com
>
> Ray McArthur
>
>
Original Message
> From: Vic Fraenckel <vfraenc1@n...>
> To: Stamp Mailing List <basicstamps@egroups.com>
> Sent: Sunday, December 03, 2000 6:11 AM
> Subject: [noparse][[/noparse]basicstamps] 5volt power supply
>
>
> > It is quite fashionable to use a 7805 regulator to provide 5 volt power
> from
> > a 12 volt power source (read car battery). Because of the large voltage
> gap
> > between the car battery and the 5 volt output, considerable power is
> wasted
> > as heat. The major advantages of using the 7805 are simplicity and cost.
A
> > power supply can be built on a tiny board at a very low cost. However,
the
> > heat becomes a problem, especially at somewhat high (300-400ma) power
> > levels.
> >
> > I am looking for a way to build a power supply on a relatively small
board
> > at a reasonable cost that could avoid, or at least minimize this thermal
> > problem. Suggestions would be appreciated as would a CC reply to my
e-mail
>
>
>
>
>
>