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Twospoons
International Hazard
Posts: 1349
Registered: 26-7-2004
Location: Middle Earth
Member Is Offline
Mood: A trace of hope...
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Electronics is a vast field - I've been doing it professionally for 35 years, and I was a hobbyist since age 8, and I'm still learning stuff.
Switching power supplies are one of those things that look simple on the surface, but actually require a lot of knowledge to build a functional
device. As usual, the devil in in the details.
Helicopter: "helico" -> spiral, "pter" -> with wings
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Rainwater
National Hazard
Posts: 987
Registered: 22-12-2021
Member Is Offline
Mood: Break'n glass & kick'n a's
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These 3 are public domain now.
Oldies but goody.
I keep all 3 on my desk just to have the equations handy and still use the protoboard to test stuff when doing work
https://archive.org/details/Radio_Shack_-_Basic_Electronics_...
https://engineering.unt.edu/ee/files/Radio_Shack_Electronics...
https://www.zpag.net/Electroniques/Kit/Radio_Shack_Electroni...
Here is a free dr level education about semiconductors
https://youtube.com/playlist?list=PLyYrySVqmyVPzvVlPW-TTzHhN...
[Edited on 24-2-2025 by Rainwater]
"You can't do that" - challenge accepted
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Twospoons
International Hazard
Posts: 1349
Registered: 26-7-2004
Location: Middle Earth
Member Is Offline
Mood: A trace of hope...
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"The Art of Electronics" by Horowitz and Hill is a very good general reference book.
Helicopter: "helico" -> spiral, "pter" -> with wings
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bnull
National Hazard
Posts: 596
Registered: 15-1-2024
Location: Home
Member Is Offline
Mood: Sneezing like there's no tomorrow. Stupid cat allergy.
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Schematics. Coupled with simulations, there is much to learned from them, specially alternative solutions to problems.
World Radio History (https://www.worldradiohistory.com/index.htm), formerly known as American Radio History, has a huge collection of electronics and radio books and
magazines.
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khlor
Hazard to Others
Posts: 111
Registered: 4-1-2014
Location: Who knows, really...
Member Is Offline
Mood: No Mood
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Helo Again, sorry for the long hiatus, work scheduled has been hectic the last two months. all time I had was the commute to and from work, so I did
simulations on my phone, I used everycircuit and ECStudio, I didn't got to simulate the whole thing as I wanted, but I did simulate bits and pieces
just so I got the idea of what to do, these simulators don't play well with the 555, both gave me a hard time, but they did plenty well with linear
circuits and simple stuff.
Now, to the business at hand, I did rebuilt the "control board/portion" for the sixth time, this time nothing fried, which is G O O D. the gate
drivers I still hadn't changed, but based on rainwater work, I might just change it a little, by replacing the bc327 and 337 for something beefier, I
think BD140/139 will do fine.
I considered the idea of elevating the ground, but since the voltage control is done only for the gate driver of the mosfets and the current design is
holding its ground, I think I will keep it this way, keep using the 7809 and work at 0 v without that idea f virtual ground. I finished assembly of
the board and here are the facts:
Picture 01: Circuit Diagram update.
As you can see, the 555 is now halted by cutting the reset pin, all is on the same ground level. I did. bit of a "level shifter" on the output pin of
the 555 and it feeds on a current divider that feeds the circuit for the mosfet gate driver, which remains the same to date(planned changes after I
decided what to do with this mess) this circuit worked just fine, RV-control is the potentimeter I use to regulate voltage and it works fine, like
before. I scoped the mosfet gate on both sides and, no more quasi-linearity issues, it is oscillating like it should with Vgs -12v. The problem, like
before, remains with current control.
As shown in the diagram, I did as rainwater suggested and made a lowpass filter, but initially it did not quite worked, then I looked at the internet
for sugestions and came up with the current control loop you can see the diagram above and situation improved, but it is still very bad, as it can be
seen on Picture 02.
Picture 02: Scoped Output
When the circuit is on voltage control mode, all is smooth, ripple bellow 0.07V(70mV) but once current control starts to kick in, things get ugly and
this, on the Picture 02 is the result. it used to be worse, but still, far from tolerable, and everyday that goes one and I think of this, makes me
question my decisions in life, I mean, I might just go forth with the idea of switched voltage control and linear current control, if any has a
suggestion on this particular issue, I am all ears, however I believe that the way my circuit works won't allow for proper current control, though, in
the future, I will make sure to go with the commercial options.
grievances aside, I am glad I decided to "reinvent the wheel" in the hardest way possible because the goal wasn't the wheel(though it was a desired
byproduct ) but the learning that came with it was absurd, the amount of things I got to at least get a glance at is incredible and the help you guys
gave is truly something else!
"NOOOOOO!!! The mixture is all WROOOOOOONG!"
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