Low voltage op amp to control high voltage series pass transistor

AI Thread Summary
The discussion revolves around designing a low drift, low ripple power supply using a low voltage op amp to control high voltage series pass transistors. The user initially employed a high voltage op amp but faced failures, prompting a shift to a low voltage op amp powered from +/- 5V. Key challenges include translating a 0-5V signal to control the +/- 40V rails while ensuring stability and preventing damage to the op amp. Suggestions include using a common emitter amplifier followed by a Darlington pair, with emphasis on feedback mechanisms to manage high voltage safely. The conversation also touches on circuit design intricacies, such as current limiting and the importance of understanding basic transistor configurations.
  • #51
meBigGuy said:
The output "MUST" swing much more as opposed to "can".

Is this the implementation you will use? Now that you understand this circuit, look at the simpler two transistor solution using T1 and T5 in http://www.bogobit.de/bogobox/

I will most like not be using it. I just HAD to understand it. I am using a NPN transistor that sinks base current from a PNP. The NPN is driven by an op amp. Pretty much how T1 and T5 are configured.
 
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  • #52
Well, I'm glad you persisted because I learned a bunch in the process.
 
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  • #53
meBigGuy said:
Well, I'm glad you persisted because I learned a bunch in the process.

Likewise. I'm glad both of you persisted.
 
  • #54
I'm just glad you guys were very helpful.
 
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