"Dude, I like making things do what they're not supposed to do."

That's all fine, but it is hard see the value in doing this for learning or any other purpose. Learn what you need to, but skip the self aggrandizement.

I did learn what I had to. I learned all of the formulae for all of the discrete components, transformers(Steel Core and Ferromagnetic), inductors while ICs have in depth datasheets. For instance MCUs and CPUs have the entire instruction set in their datasheets.

I'm learning EE to be inventive, not just to perform mundane tasks.

 

I did learn what I had to. I learned all of the formulae for all of the discrete components, transformers(Steel Core and Ferromagnetic), inductors while ICs have in depth datasheets. For instance MCUs and CPUs have the entire instruction set in their datasheets.

I'm learning EE to be inventive, not just to perform mundane tasks.

Your disdain for mundane tasks is going to lead to future disappointment. Good engineering is mostly the competent performance of mundane tasks.

 

You will need more peripheral components to do a less better job than you would with a proper chip, but go ahead and learn.....

 

The word that comes to mind is hubris. Just because a thing can be done does not necessarily mean that doing it is a good idea. If you want to do it then do it, and stop wasting our time trying to make everything look like a nail because the only tool you have is a hammer.

Dude what is wrong with you? SMH...

 

This forum is horrible and I'll never use it again. I had no Idea how many negative people (with the exception of 2 or 3) there were here. I came here for knowledge and all I left with were insults. .

I understand the NE555 isn't the best PWM chip for this purpose but, why did anyone post anything other than an answer to my question?

Your disdain for mundane tasks is going to lead to future disappointment. Good engineering is mostly the competent performance of mundane tasks.

You make it sound like bad IT (Inability to think outside of the box).
Nearly every attempt at something new ends in failure and disappointment. However, with perseverance nearly any task can be completed.

 

You will need more peripheral components to do a less better job than you would with a proper chip, but go ahead and learn.....

More peripheral components will not necessarily do a "less better" job. I do believe it's more about how you use those peripheral components and which ones you use.

 

This forum is horrible and I'll never use it again. I had no Idea how many negative people (with the exception of 2 or 3) there were here. I came here for knowledge and all I left with were insults. .

I understand the NE555 isn't the best PWM chip for this purpose but, why did anyone post anything other than an answer to my question?


You make it sound like bad IT (Inability to think outside of the box).
Nearly every attempt at something new ends in failure and disappointment. However, with perseverance nearly any task can be completed.

It's unfortunate that you've received the treatment that you did. It was clear pretty early on in your thread that your goal was to learn about these kinds of supplies by trying to implement one from the ground up with little in the way of pre-packaged solutions. I applaud that. It's also pretty evident that you have used the pre-packaged solutions successfully in the past and are now trying to gain an in-depth appreciation for what the underlying issues are and how to overcome them. You expected to run into problems and you have -- and you seem to have been dealing with them as they arise and learning much in the process.

I can only recommend that you ignore the naysayers and focus on the good interactions. Any forum is going to be a mix of both.

 

Your disdain for mundane tasks is going to lead to future disappointment. Good engineering is mostly the competent performance of mundane tasks.

Isn't it pretty evident that the TS has been doing a LOT of the "mundane tasks" in getting his design to the point that it is? He is trying to learn underlying principles and concepts by applying them at a low level. Using a pre-packaged, off-the-shelf solution is pretty much mutually exclusive to his goals. He is NOT trying to make a polished, optimized solution. He is trying to learn from the process of designing a solution that works and than improving that solution. He expects to run into problems and is dealing with them as they arise. In the process he is learning a lot about the issues associated with these kinds of circuits and how to solve them.

If his approach is unacceptable to you and some others because he won't use the purpose-designed chips that you recommended, then just wish him well and move on (or just move on). There is no need to keep badgering him.

 

It's unfortunate that you've received the treatment that you did. It was clear pretty early on in your thread that your goal was to learn about these kinds of supplies by trying to implement one from the ground up with little in the way of pre-packaged solutions. I applaud that. It's also pretty evident that you have used the pre-packaged solutions successfully in the past and are now trying to gain an in-depth appreciation for what the underlying issues are and how to overcome them. You expected to run into problems and you have -- and you seem to have been dealing with them as they arise and learning much in the process.

I can only recommend that you ignore the naysayers and focus on the good interactions. Any forum is going to be a mix of both.

I Thank you and Dick, for understanding my position. You've hit the nail on the head.

 

I Thank you and Dick, for understanding my position. You've hit the nail on the head.

As you can tell from the likes my posts got, Dick and I are not alone in your corner.

In fact, you are doing something that I would love to do someday -- I have no background in SMPS circuits and would like to do this same type of design at this same level for the same reasons you are. I think that, this might even make a good addition to the Completed Projects forum once you get it all done, particularly if the write-up is centered on the issues involved and how different parts of the circuit address them.

Good luck to you.

 

It appears that your schematic was drawn in LTSpice. Would you please post your simulation file and if you have some component models that don't normally come with the package please post those files too so we can get a closer look at the problem?

 

We all stick the keyboard in our mouths from time to time. Please stay around and get to know us properly.

 

Gilbert;
Having designed PSUs for a living................
An important issue with any offline supply is the startup current. Once that it starts, it self biases, but the first hundred milliseconds are very, very, very critical.

Your startup circuit is a little convoluted. Would you kindly explain it?

 

It appears that your schematic was drawn in LTSpice. Would you please post your simulation file and if you have some component models that don't normally come with the package please post those files too so we can get a closer look at the problem?

I did post a sim file earlier on when you requested it, but the models came in a bundle of models that I got from the LTWiki

 

As you can tell from the likes my posts got, Dick and I are not alone in your corner.

In fact, you are doing something that I would love to do someday -- I have no background in SMPS circuits and would like to do this same type of design at this same level for the same reasons you are. I think that, this might even make a good addition to the Completed Projects forum once you get it all done, particularly if the write-up is centered on the issues involved and how different parts of the circuit address them.

Good luck to you.

Thank you!

I've actually changed the schematic quite a bit since you last saw it. I've added a second boost inductor operating on an opposite phase to provide less ripple on the output and I've Improved on the ZeroCrossing detection circuit.

I'm actually getting close to build, but there are a few equations I need to work out for the inductor windings and transformers. As you probably already know, the outcomes in sim and reality can be very different. So I've been concentrating on the physics of the magnetics in the circuit ( very interesting stuff) because I'm planning on winding everything myself.

Once I've got a working, stable PSU, I'll be more than happy to post it as a completed project.

 

Gilbert;
Having designed PSUs for a living................
An important issue with any offline supply is the startup current. Once that it starts, it self biases, but the first hundred milliseconds are very, very, very critical.

Your startup circuit is a little convoluted. Would you kindly explain it?

The schematic you saw is completely different at this juncture, but the basic rundown was pre-regulation until the boosted voltage reached the desired voltage of 360V DC then it would startup the switching cycle for the flyback coupled inductor, shutting off the pre-regulator once the output of the flyback reached optimal voltage where it would take over powering the circuit. There is a Zero Crossing detection circuit that would prevent any startup switching to occur during an AC half cycle. The entire circuit that you see posted was designed to power a full bridge topology. I removed the input cap placed before the boost inductor because that isn't really PFC is it, lol. I've learned quite a bit since then.

You say the first 100ms is critical. I tend to act on the first 16ms following the first detectable zero crossing and work from there(I won't allow any HV switching to occur). I just figured that was the best way to go being Vs is at zero and will rise to peak within 8ms.
Can you please elaborate?

You've done this for a living, so you're exactly the guy who's brain I'd like to pick, lol.
I've been having issues getting straight answers on magnetics. The physics behind MMF is so beautiful, yet confusing, when I ask questions on it. The books say one thing, I think I've got it, then forum users seem to each have their own understanding of it.