Super Regulator, swedish bikini team sidetrack

[Fred Dieckmann]

You've all been asleep, you would not believe me
Them voices tellin' me, you will soon receive me
Standin' on the beach, the sea will part before me
Fire wheel burning in the air!

You will follow me and we will ride to glory, way up, the middle of
the air!

And I'll call down thunder and speak the same and my work fills the
sky with flame
and might and glory gonna be my name and men gonna light my way.

[mrfeedback]

Fred Dieckmann
Fred is dressed in a casual sweater, and carries that sad,
serious look of a man who sees too far and cares too much.
Priceless.

[jam]

Well let's see...........................

http://www.muppetworld.com/cooking/




Jam

[Christer]

Jam, how on earth did you get that idea? Did I miss Fred saying
köttbullar somewhere??

[jam]

Well, Fred has a musical side to him, by the way what is 'kottbuller'?

I better hide now, Fred knows where I live!

[andy_c]

Originally posted by Fred Dieckmann
>100 mA DC. The regulators will work better with load currents above 100 mA
than low current loads like 10 or 20 mA.

There is an extremely simple explanation for this for anybody who knows a little electronics.....

Since there's two major low-frequency poles (one from the op-amp and one from the pass transistor output resistance and load capacitor), the phase lag of the loop gain is 180 degrees at frequencies much higher than the second pole. Then you hit the series resonant frequency of the load capacitor which is about 100 kHz. At that frequency, the phase lag of the loop gain is about 90 degrees because the load capacitor is purely resistive there. If you run the pass transistor at low currents, the pole due to the load capacitor and pass transistor becomes lower in frequency, reducing the unity loop gain frequency accordingly. This can cause the phase lag at the unity loop gain frequency to get larger because you haven't seen all the benefits of the reduced phase lag due to hitting the series resonant frequency of the capacitor yet. A further effect happens due to the reduced ft of the pass transistor at low currents. This causes the output inductance of the pass transistor to increase, which can cause a really nasty increase in phase lag because of its interaction with the load capacitor.

At any rate, that's what I saw when simulating a +90V version of this thing with a Darlington configuration for the pass transistor. The transient response to a step of load current sucked at low currents due to the poor stability margin.

[Elso Kwak]

Hi,
I have a hard time understanding the Swedish Chef. My knowledge of the Swedish is nill and the Swedish Chef is hard to understand. Fred could you provide a English translation?

[Christer]

Originally posted by Elso Kwak
Hi,
I have a hard time understanding the Swedish Chef. My knowledge of the Swedish is nill and the Swedish Chef is hard to understand. Fred could you provide a English translation?

Just don't fall into the trap of believing that we swedes
understand him either.

[Elso Kwak]

Originally posted by Christer


Just don't fall into the trap of believing that we swedes
understand him either.

Christer, This thread is sooooo confusing!

[Christer]

Originally posted by Elso Kwak



Christer, This thread is sooooo confusing!

So it's like most other long threads on this forum then.