Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Feedback loop of TL431 based linear regulator?

cupoftea

Advanced Member level 4
Joined
Jun 13, 2021
Messages
1,158
Helped
28
Reputation
56
Reaction score
55
Trophy points
48
Activity points
6,389
Hi,
Is the feedback loop of the attached 60v to 5v linear regulator the way you would do it?
I am treating the TL431 like a “normal” opamp.
 

Attachments

  • 5V Linear regulator.pdf
    184.1 KB · Views: 39

betwixt

Super Moderator
Staff member
Joined
Jul 4, 2009
Messages
15,523
Helped
5,026
Reputation
10,076
Reaction score
4,864
Trophy points
1,393
Location
Aberdyfi, West Wales, UK
Activity points
131,559
You can do it that way but what does the 5V rail have to supply power to? If it is just the circuitry shown you can probably manage without the two pass transistors. If the load is fairly constant you can probably remove the capacitors from around the TL431 as well as the supply should be clean of transients. There is no power advantage to dropping 55V this way, you could use a single resistor and Zener diode, the V*I in the dropping components will be the same.

Brian.
 

cupoftea

Advanced Member level 4
Joined
Jun 13, 2021
Messages
1,158
Helped
28
Reputation
56
Reaction score
55
Trophy points
48
Activity points
6,389
Thanks, sorry i should have said, it could be up to 10mA flowing in that opto....then again, maybe as you suggest, i could use less components and just use a TO220 NPN /zener/resistor...

...than again, i may just leave it like it is...but....
Make R38 = 0R
Not fit C38, C37, R40, C36, R39, R37, C25

...I mean, d'you think for this low power with just 10mA, i can do without the feedback compensation?
 

LaTeX Commands Quick-Menu:

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top