LM7812 Data Sheet Parameter

[Animesh Maurya]

I was reading the data sheet of LM7812 voltage regulator, here two
parameters : Short Circuit Output Current & Peak Output Current are
confusing me.

Short Circuit Output Current & Peak Output Current for LM7812 are
350mA and 2.2A respectively.

According to me Peak Output Current will occur when output is short
circuited, so the values for both the above parameters should be same.

Textbook says that Peak Output Current occurs for a short duration of
time, for what duration of time will I get 2.2 A current ?

I need some explanation.

Regards

Animesh Maurya

 

[Thomas C. Sefranek]

"Animesh Maurya" <animesh_m@eudoramail.com> wrote in message
news:9f6c9f5d.0310270355.452fbbc9@posting.google.com...

I was reading the data sheet of LM7812 voltage regulator, here two
parameters : Short Circuit Output Current & Peak Output Current are
confusing me.

Short Circuit Output Current & Peak Output Current for LM7812 are
350mA and 2.2A respectively.

According to me Peak Output Current will occur when output is short
circuited, so the values for both the above parameters should be same.

Textbook says that Peak Output Current occurs for a short duration of
time, for what duration of time will I get 2.2 A current ?

I need some explanation.

Regards

Animesh Maurya

Short circuit curent is the current foldback value.
This is a protection.
With the proper attention to the maximum dissipation,
you may expect to get 2.2 amps when operating normally.


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*
| __O Thomas C. Sefranek WA1RHP@ARRL.net
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[Animesh Maurya]

animesh_m@eudoramail.com (Animesh Maurya) wrote in message news:<9f6c9f5d.0310270355.452fbbc9@posting.google.com>...

I was reading the data sheet of LM7812 voltage regulator, here two
parameters : Short Circuit Output Current & Peak Output Current are
confusing me.

Short Circuit Output Current & Peak Output Current for LM7812 are
350mA and 2.2A respectively.

According to me Peak Output Current will occur when output is short
circuited, so the values for both the above parameters should be same.

Textbook says that Peak Output Current occurs for a short duration of
time, for what duration of time will I get 2.2 A current ?

I need some explanation.

Regards

Animesh Maurya

At what temperature thermal shut down takes place.

Thanks

 

[Luhan Monat]

Animesh Maurya wrote:

At what temperature thermal shut down takes place.

Thanks

I don't know the exact temperature, but its hot enough to burn your
fingers!!!
--
Luhan Monat
"LuhanKnows" At 'Yahoo' dot 'Com'
http://members.cox.net/berniekm

 

[Animesh Maurya]

Luhan Monat <bogus@yahoo.com> wrote in message news:<51uob.114938$La.106593@fed1read02>...

Animesh Maurya wrote:



At what temperature thermal shut down takes place.

Thanks

I don't know the exact temperature, but its hot enough to burn your
fingers!!!

Surely it will burn my fingers.

But I can make a guess about that temperature, data sheet says that
operating temperature is in between 0 to 125 C.

So one can think that thermal shut down may take place at temperature
above 125 C.

Iam not sure I just want to confirm it. What do you think?

Animesh Maurya

 

[Christian HOSTELET]

Le 01/11/2003 12:11:09, a écrit:

Luhan Monat <bogus@yahoo.com> wrote in message news:<51uob.114938$La.106593@fed1read02>...
Animesh Maurya wrote:



At what temperature thermal shut down takes place.

Thanks

I don't know the exact temperature, but its hot enough to burn your
fingers!!!

Surely it will burn my fingers.

But I can make a guess about that temperature, data sheet says that
operating temperature is in between 0 to 125 C.

So one can think that thermal shut down may take place at temperature
above 125 C.

Iam not sure I just want to confirm it. What do you think?

Animesh Maurya

Hello,

I've 've found a japanese site on which they are giving some explanation on
protection circuits in 3-Terminal Voltage Regulators. The site URL is
http://www.njr.co.jp/index_e.htm (for english; no french :-( Then look for
Products Data Sheets -> Integrated Circuits. Then LINEAR IC. In the POWER
SUPPLY paragraph look at the 3rd document.

Hope this will help

--
Christian - Grenoble