Problem with TL431 regulation, plse help me.

[commstech]

Hi!

It is almost there- everything right except that You have 2.5mA running through the voltage divider. So if You want better calculation then add that current to Your 55mA - it would not affect the value of the series resistor much. Also if the TL431 is running to hot (with 10mA) than put a little bit bigger series resistor and that is it.
You got the point of it.

Please don't thank me for the patience- You don't know how much mistakes and don't know's I make 🙁 . It is my duty to help You since a lot of guys also helped me. I AM GLAD THAT I CAN HELP YOU IN SOME WAY....😀


best regards
daniel

Hi Daniel,
It is working perfectly well now!! Thanks !!! and thanks to all who helped to answer my queries.

🙂 🙂
Nick

 

[peranders]

What minimum current does TI's file use for the TL431?

I think it is 1mA, but I read on this forum that 10mA as a minimum current is recommended

It depends what you are using it for but at max load, the 431 current should not go under 0.5 mA.

 

[sparkle]

Hi Daniel,
It is working perfectly well now!! Thanks !!! and thanks to all who helped to answer my queries.

🙂 🙂
Nick

I'm happy beacuse of that..
regards
daniel

 

[ridwans]

ask to calculate value of R

Hallo.
i want to ask anyone whose know
how to calculate R
(R1,R2,R3 /R1A,R2A,R2B) value of combination Reg LM317/337 and TL 341

i plant to use for reg +15 -15 output current 300Ma.
input volate +- 20V dc
output 15V
output current 300Ma - 600Ma
this the schematic.

please heelp anyone.
thx

 

[peranders]

300 mA is too much I'm afraid.

http://focus.ti.com/lit/ds/symlink/tl431.pdf
Check figure 21.

I assume that you already have download the datahseet?

The LM317 is a separate circuit. I recommend that you download this datasheet also.

 

[AndrewT]

that's basically what I told him on the other thread.
Naughty boy posted the same thing twice.

 

[ridwans]

that's basically what I told him on the other thread.
Naughty boy posted the same thing twice.

hi andrew..
in what treath the reference.
sorry i dont know that i can't post same topic.
thx

 

[AndrewT]

in what treath the reference.

is this a question?
Post again on the other thread and leave the Digital thread.