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Can someone PLEASE check schematic

Cube777

Cube777

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Hi, I designed this CC and CV power supply that runs of a standard 12V transformer, can someone please check that this schematic is correct. My electronics knowledge is not very good and when I tried comparing it to Wolfman's power supply I couldn't open the schematic.SC1 and SC2 are an digital volt- and ammeter. Any suggestions would be greatly appreciated!

hjgf_zps3d8cd90b.jpg


EDIT: I can change the LM338 to a LM317 but prefer not to as the LM338 can handle higher currents.
 
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Cyparagon

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That. Is. Horrible.

It looks like somebody threw a bin of BJTs in a spider web. Sorry, but it needs to be redrawn so it's readable.

Cube777 said:
can someone please check that this schematic is correct.
Click to expand...

Correct for what? Probably not. What sort of performance are you shooting for? I suspect you can do it with 80% fewer parts.
 
Hiemal

Hiemal

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Jeez...

Yeah, what Cyparagon said.

You can make an adjustable CC-CV power supply using an LM338, and a voltage regulator after it...

That's how I made a custom battery charger.

The LM338 handles the CC aspect, then once it reaches 4.20 volts, the CV part kicks in preventing the voltage from rising any higher. It's actually pretty cool.
 
Cube777

Cube777

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Hi, I am very sorry for horrible schematic. It's goal is to switch between CC an CV and at both modes read the the voltage and current. Both modes are controlled by the potentiometer and the reason for all the transistors is so that the two regulator's output don't touch each other, making that it is not CC or CV. I will try to redraw the schematic once I get home this afternoon.
 
Cyparagon

Cyparagon

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Just put the CC regulator in series before the CV regulator. Throw all those BJTs away. The pot action won't be linear and the output can only go down to 1.25V though.
 
Sigurthr

Sigurthr

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I think I spent too much time trying to follow the traces and now my brain is leaking out of my ears.

This reminds me of a joke piece of sheet music where the "composer" purposely obfuscates it to the point of illegibility.

Personally, I got a chuckle out of how none of the BJTs are biased.

Cyparagon and Le Quack are right; it takes TWO ICs (and their decoupling/filter caps, and control pots), that is ALL. A CC stage feeds a CV stage; the CV stage cannot draw more current than the CC stage supplies, and the CV stage adjusts the voltage supplied to the load.

Edit: found the sheet music:
http://imageshack.us/a/img31/7641/faeriesaire.gif
 
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foulmist

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oh my god :D

I am sure noone will ever be able to help you with that schematic :( :D

look throughout the internet (gooogle) there are plenty of CC/CV schematics that might work better than this (if this works at all) :beer:
 
Cube777

Cube777

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Thank you for all the replies, I tend to over-complicate things. Will put the CC in front of the CV. :thanks:
 
Hiemal

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Don't be too offended :p

Some people on the forums tend to be skeptical of new people. But yeah, CC then CV and you have your awesome power supply. Not CV then CC.
 
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