Issacsutt

modified 7 years ago

Voltage Regulator using Feedback

298

05:00:04

Increase input voltage from 1v to about 1kV, you'll see it flatten out at around 4.8v on the blue trace... and remain pretty steady throughout. The green trace is a very simple buffer stage, nothing fancy; which is why it's a couple 10ths of a volt lower. I've ran into many complications trying to put together a voltage regulator circuit that could supply enough power without loading down too much on the buffer stage...  come to find out, it was because I've been using a zener diode when I should've been using feedback, now that makes things a whole lot Less complicated to achieve even better results! 
Thanks to Hurz! :)

published 8 years ago

hurz

8 years ago

I dont like messy circuits

hurz

8 years ago

But in principle its this while you have two more gain stages which will sharpen the regulating behaviour. http://everycircuit.com/circuit/5821666767929344

Issacsutt

8 years ago

Ok cool, thank you!

Issacsutt

8 years ago

Also, is there any other way to further stabilize this circuit besides adding more states to improve gain?

hurz

8 years ago

OpAmps do have open loop gain of 1Mio if you want. So this is plenty enough

GingerKing

8 years ago

See what actually happens --> 10ns/s

hurz

8 years ago

Right, such a lot gain can cuz big trouble 😁 an OpAmp would also need a cap as frequency compensation to not start oscillating.

Issacsutt

8 years ago

What is Mio?

hurz

8 years ago

1000000

Issacsutt

8 years ago

I mean, io? I know current is usually i, and voltage v, but io?

Issacsutt

8 years ago

Oh never mind, now I see where you said it was open loop gain of... just didn't notice that the first time

Issacsutt

8 years ago

Thanks Hurz, for pointing out how to use feedback rather than a zener diode! 🙂

hurz

8 years ago

The difference of control and regulating, even engineers do that wrong.

Issacsutt

8 years ago

Wow! I guess that's how you learn huh

njan24

8 years ago

Has anyone tested it with rectified AC? Would be interesting to learn how this works.

Issacsutt

8 years ago

Sure, Try it out!

njan24

8 years ago

I just did. I wonder why the negative wave is not being rectified.

njan24

8 years ago

http://everycircuit.com/circuit/4659220179058688

Issacsutt

8 years ago

Ok, it is rectifying the negative half too, but you have to use the volt meter between the two diode pairs to see it, you couldn't really see it before, because the scope compares everything to a 0v ground reference and isn't considering the negative half on the one side of your bridge rectifier. http://everycircuit.com/circuit/5988960575946752

Issacsutt

8 years ago

http://everycircuit.com/circuit/4506990700396544

njan24

8 years ago

Ah, that makes more sense. Thanks!

Issacsutt

8 years ago

No problem man!

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