Was- Stamps and automotive applications. NOW-automotive po...
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In a message dated 8/14/2003 11:42:26 AM Pacific Daylight Time,
madams@a... writes:
> I have a similar problem and was wondering if anyone has a rock solid power
> supply design for automotive applications. I have a .jpg with what I have,
> why it doesnt work and suggestions if I can post it here. Just let me know.
> Here is what was suggested using a LM2931. I think my major problem was the
> use of a LM341.
>
> Mark
>
> The best route to follow is:
> Power in to a parallel 1000pf/1000v cap to ground connected to a series
> diode (1N4004) connected to a 30v MOV(varistor)to ground followed by a
> 330uF 35 v electrolytic feeding a LM2931 low dropout 5v regulator
> properly heat sinked. The output feeds a 0.1uf and 1.0uF in parallel.
> This will get you a great starting point.
> Make sure all module inputs have .01uf to ground.
> Make sure all ICs have 0.1uf across power and ground.
> Make sure your resonator/crystal has the proper series resistance.
> Make all traces as short as possible and use 2-z copper if possible on
> your PCB.
> Finally, place your design in a grounded metal box and you are sure to
> have success.
>
>
Along with the items mentioned above.....automotive "power" is usually dirty.
If you continue to have trouble after employing the items above, you may want
to consider a high quality low noise DC to DC converter, which will isolate
the stamp from the vehicle power and ground. Digital I/O is then input and
output from the stamp with Opto isolators......
These suggestions however cost $$ and board space......
[noparse][[/noparse]Non-text portions of this message have been removed]
madams@a... writes:
> I have a similar problem and was wondering if anyone has a rock solid power
> supply design for automotive applications. I have a .jpg with what I have,
> why it doesnt work and suggestions if I can post it here. Just let me know.
> Here is what was suggested using a LM2931. I think my major problem was the
> use of a LM341.
>
> Mark
>
> The best route to follow is:
> Power in to a parallel 1000pf/1000v cap to ground connected to a series
> diode (1N4004) connected to a 30v MOV(varistor)to ground followed by a
> 330uF 35 v electrolytic feeding a LM2931 low dropout 5v regulator
> properly heat sinked. The output feeds a 0.1uf and 1.0uF in parallel.
> This will get you a great starting point.
> Make sure all module inputs have .01uf to ground.
> Make sure all ICs have 0.1uf across power and ground.
> Make sure your resonator/crystal has the proper series resistance.
> Make all traces as short as possible and use 2-z copper if possible on
> your PCB.
> Finally, place your design in a grounded metal box and you are sure to
> have success.
>
>
Along with the items mentioned above.....automotive "power" is usually dirty.
If you continue to have trouble after employing the items above, you may want
to consider a high quality low noise DC to DC converter, which will isolate
the stamp from the vehicle power and ground. Digital I/O is then input and
output from the stamp with Opto isolators......
These suggestions however cost $$ and board space......
[noparse][[/noparse]Non-text portions of this message have been removed]
Comments
for something that will eliminate it completely.
Can I post a JPG here?
Mark
Original Message
From: smartdim@a... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=7hEFDqTicwC2M4rYZfNFTE0EJ9fUJ-BWkhhJuEXwJIKP9A_wYmMFR6Y6f9gwBZFPOw43atF-KQ]smartdim@a...[/url
Sent: Thursday, August 14, 2003 2:12 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Was- Stamps and automotive applications.
NOW-automotive po...
In a message dated 8/14/2003 11:42:26 AM Pacific Daylight Time,
madams@a... writes:
> I have a similar problem and was wondering if anyone has a rock solid
power
> supply design for automotive applications. I have a .jpg with what I
have,
> why it doesnt work and suggestions if I can post it here. Just let me
know.
> Here is what was suggested using a LM2931. I think my major problem was
the
> use of a LM341.
>
> Mark
>
> The best route to follow is:
> Power in to a parallel 1000pf/1000v cap to ground connected to a series
> diode (1N4004) connected to a 30v MOV(varistor)to ground followed by a
> 330uF 35 v electrolytic feeding a LM2931 low dropout 5v regulator
> properly heat sinked. The output feeds a 0.1uf and 1.0uF in parallel.
> This will get you a great starting point.
> Make sure all module inputs have .01uf to ground.
> Make sure all ICs have 0.1uf across power and ground.
> Make sure your resonator/crystal has the proper series resistance.
> Make all traces as short as possible and use 2-z copper if possible on
> your PCB.
> Finally, place your design in a grounded metal box and you are sure to
> have success.
>
>
Along with the items mentioned above.....automotive "power" is usually
dirty.
If you continue to have trouble after employing the items above, you may
want
to consider a high quality low noise DC to DC converter, which will isolate
the stamp from the vehicle power and ground. Digital I/O is then input and
output from the stamp with Opto isolators......
These suggestions however cost $$ and board space......
[noparse][[/noparse]Non-text portions of this message have been removed]
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madams@a... writes:
> Yes, that is what I have now, but those things are expensive. I am looking
> for something that will eliminate it completely.
>
> Can I post a JPG here?
>
> Mark
Don't think you can post a jpeg...
Another possible alternative is an LC filter.......the values of L and C are
dependant on what noise you have, you would need a good quality o-scope to see
the frequency of the noise and design the filter accordingly
+v cap to gnd L cap to gnd +v to stamp
[noparse][[/noparse]Non-text portions of this message have been removed]
regulator and I think it was the problem. I was just following the
improvements, but seem to be having a hard time finding that rock solid
design without the dc-dc convertor.
Mark
Original Message
From: smartdim@a... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=MPOpEy09Kp_p2bGexYAUI0yNUAcZDIMPBl-KsP0NjzlwNB3zc4qPzb45E6-y6HNPVaEbTo015Q]smartdim@a...[/url
Sent: Thursday, August 14, 2003 2:56 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Was- Stamps and automotive applications.
NOW-automotive po...
In a message dated 8/14/2003 12:27:58 PM Pacific Daylight Time,
madams@a... writes:
> Yes, that is what I have now, but those things are expensive. I am
looking
> for something that will eliminate it completely.
>
> Can I post a JPG here?
>
> Mark
Don't think you can post a jpeg...
Another possible alternative is an LC filter.......the values of L and C are
dependant on what noise you have, you would need a good quality o-scope to
see
the frequency of the noise and design the filter accordingly
+v cap to gnd L cap to gnd +v to stamp
[noparse][[/noparse]Non-text portions of this message have been removed]
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/