Feedback loop of TL431 based linear regulator?

[cupoftea]

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.

 

[betwixt]

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]

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?

 

[Johnelectronics]

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.

Did you analyze the stability of the regulator?

 

[FvM]

Make R38 = 0R
Not fit C38, C37, R40, C36, R39, R37, C25

You don't necessarily need the complex cpmpensation schema, but I would be surprized if the regulator is stable without basic PI compensation.