wide range voltage input

L

ltj

Guest
If you had a small 3.3V, 50mA circuit how could you make it to accept a
5-24VDC input range? Cost is an issue.
 
ltj wrote:
If you had a small 3.3V, 50mA circuit how could you make it to accept a
5-24VDC input range? Cost is an issue.
Click to expand...
Are you talking about responding to logic signals or measuring analog
signals?

--
John Popelish
 
oops...for powering the circuit. A regulator will get too hot if I drop too
much voltage across it, so what is a good way to have a wide power input
range?

"John Popelish" <jpopelish@rica.net> wrote in message
news:40AAD8B4.EC2096A8@rica.net...
ltj wrote:

If you had a small 3.3V, 50mA circuit how could you make it to accept a
5-24VDC input range? Cost is an issue.

Are you talking about responding to logic signals or measuring analog
signals?

--
John Popelish
Click to expand...
 
ltj wrote:
"John Popelish" <jpopelish@rica.net> wrote in message
news:40AAD8B4.EC2096A8@rica.net...
ltj wrote:

If you had a small 3.3V, 50mA circuit how could you make it to accept a
5-24VDC input range? Cost is an issue.

Are you talking about responding to logic signals or measuring analog
signals?

oops...for powering the circuit. A regulator will get too hot if I drop too
much voltage across it, so what is a good way to have a wide power input
range?
Click to expand...
A switching regulator converts one voltage to another with minimal
power loss. Here is a tutorial on the subject to get you started.
http://www.national.com/appinfo/power/files/f5.pdf

This page on the National Semiconductor site will design a switching
regulator for you, to your specifications:
http://www.national.com/appinfo/power/

That said, 50 ma drawn from a 24 volt source represents only 1.2
watts, total. So a linear regulator would have to waste no more than
(24-3.3)*.05=1.03 watts. That is about what a square inch of heat
sink could dump.

--
John Popelish
 
"John Popelish" <jpopelish@rica.net> wrote in message
news:40AB7C9D.ACD619E4@rica.net...
A switching regulator converts one voltage to another with minimal
power loss. Here is a tutorial on the subject to get you started.
http://www.national.com/appinfo/power/files/f5.pdf

This page on the National Semiconductor site will design a switching
regulator for you, to your specifications:
http://www.national.com/appinfo/power/

That said, 50 ma drawn from a 24 volt source represents only 1.2
watts, total. So a linear regulator would have to waste no more than
(24-3.3)*.05=1.03 watts. That is about what a square inch of heat
sink could dump.

--
John Popelish
Click to expand...

Wow, so helpful.!

A switching regulator is what I'm looking for.

This is a MUST READ for rookies!
http://www.national.com/appinfo/power/files/f5.pdf.

Don't know what I'd do without S.E.(...),
Thank you very much
 
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