building my own PSU and don't know what parts to choose

[17030644]

EDIT: THIS PSU WON'T BE INSTALLED IN ANY COMPUTER, IT'S JUST A DIY PROJECT THAT NEEDS TO SHOW ONE APPLICATION OF TRANSISTORS

 

Ofc this ARE NOT all the parts, just the main components for an ATX SMPS

 

I have no idea on what transformer, inductors, X, Y capacitors, resistors to choose.

 

I just selected stuff with similar voltage/current/capacitance rating to what I read on PSU reviews

 

This is the store I used:

 

https://agelectronica.com/index.php

 

Are this things OK?

 

1X 150V RMS / 395V CLAMPING VARISTOR
https://hardtofind.com.mx/pdfs/textos/2/20XD241K.PDF

 

1X 1.3 OHM 12 AMP TERMISTOR
https://hardtofind.com.mx/pdfs/textos/T/TEMIORES.PDF

 

4X 600V 10A RECTIFYING DIODES
https://hardtofind.com.mx/pdfs/textos/1/10A6.PDF

 

2X 120UF 420V BULK CAPACITORS
https://hardtofind.com.mx/pdfs/textos/S/SH.PDF

 

2X 500V 12A N-CHANNEL MOSFETS (for switching)
https://hardtofind.com.mx/pdfs/textos/2/2SK3568.PDF

 

1X 55V 80A N-CHANNEL MOSFET (FOR 12V)
https://hardtofind.com.mx/pdfs/textos/S/ST80N506.PDF

 

3X 60V 70A N-CHANNEL MOSFET (OTHER OUTPUTS)
https://hardtofind.com.mx/pdfs/textos/F/FS70UM06.PDF

 

2X 2200UF 16V CAPACITORS (FOR 12V)
https://hardtofind.com.mx/pdfs/textos/C/CE-XXYY-TEAPO.PDF

 

2X 2700UF 6.3V CAPACITORS (OTHER OUTPUTS)
https://hardtofind.com.mx/pdfs/textos/C/CE-XXYY-TEAPO.PDF

[Wolly9102]

Why do even want to make an PSU? It's safer for you and your PC if you don't.

[LukeSavenije]

i hope you know what you doing...

[Curious Pineapple]

1 hour ago, 17030644 said:

Ofc this ARE NOT all the parts, just the main components for an ATX SMPS

 

I have no idea on what transformer, inductors, X, Y capacitors, resistors to choose.

 

I just selected stuff with similar voltage/current/capacitance rating to what I read on PSU reviews

 

This is the store I used:

 

https://agelectronica.com/index.php

 

Are this things OK?

 

1X 150V RMS / 395V CLAMPING VARISTOR
https://hardtofind.com.mx/pdfs/textos/2/20XD241K.PDF

 

1X 1.3 OHM 12 AMP TERMISTOR
https://hardtofind.com.mx/pdfs/textos/T/TEMIORES.PDF

 

4X 600V 10A RECTIFYING DIODES
https://hardtofind.com.mx/pdfs/textos/1/10A6.PDF

 

2X 120UF 420V BULK CAPACITORS
https://hardtofind.com.mx/pdfs/textos/S/SH.PDF

 

2X 500V 12A N-CHANNEL MOSFETS (for switching)
https://hardtofind.com.mx/pdfs/textos/2/2SK3568.PDF

 

1X 55V 80A N-CHANNEL MOSFET (FOR 12V)
https://hardtofind.com.mx/pdfs/textos/S/ST80N506.PDF

 

3X 60V 70A N-CHANNEL MOSFET (OTHER OUTPUTS)
https://hardtofind.com.mx/pdfs/textos/F/FS70UM06.PDF

 

2X 2200UF 16V CAPACITORS (FOR 12V)
https://hardtofind.com.mx/pdfs/textos/C/CE-XXYY-TEAPO.PDF

 

2X 2700UF 6.3V CAPACITORS (OTHER OUTPUTS)
https://hardtofind.com.mx/pdfs/textos/C/CE-XXYY-TEAPO.PDF

My advice is stop now before you throw hundreds at a project you won't be able to complete. Power supplies are not easy things to build unless you plan on making a linear supply, in which case good luck drawing potentially hundreds of amps from the grid, and getting rid of kilowatts of heat.

 

There's thermal issues to consider, choosing switching controllers, PCB design, filtering, isolation, plenty of maths, the expense of tools and test gear, the list really is quite long.

[17030644]

1 hour ago, Wolly9102 said:

Why do even want to make an PSU? It's safer for you and your PC if you don't.

THIS WON'T BE INSTALLED IN ANY PC it's just a proyect for semiconductors and I have to design a circuit that shows a usecase for transistors

1 hour ago, Mr. horse said:

Strongly agree. And this is coming from someone that has made tube amps and repairs old CRT TVs.

 

if you do know how to make a PSU then grate. Go for it. But if you never done anything like this or are not highly educated with electronics It would be a grate idea to not to make your own PSU.  

It's for a project but the point is to learn

1 hour ago, NunoLava1998 said:

-SNIP-

 

@jonnyGURU how bad are the parts he chose

If you are not giving any useful advice on why the parts are bad just don't post

36 minutes ago, Curious Pineapple said:

My advice is stop now before you throw hundreds at a project you won't be able to complete. Power supplies are not easy things to build unless you plan on making a linear supply, in which case good luck drawing potentially hundreds of amps from the grid, and getting rid of kilowatts of heat.

 

There's thermal issues to consider, choosing switching controllers, PCB design, filtering, isolation, plenty of maths, the expense of tools and test gear, the list really is quite long.

I see, thanks for the info

Edited April 14, 2019 by W-L
Moderation Content

[17030644]

1 hour ago, Mr. horse said:

I am from mexico by the way

 

Edit:

mouser electronics is a grate place for buying parts for projects like this. 

 

[W-L]

Please keep discussion related to the topic at hand. 

 

 

-Thread Cleaned and Moved to Hobby Electronics- 

[Curious Pineapple]

2 minutes ago, 17030644 said:

THIS WON'T BE INSTALLED IN ANY PC it's just a proyect for semiconductors and I have to design a circuit that shows a usecase for transistors

It's for a project but the point is to learn

If you are not giving any useful advice on why the parts are bad just don't post

I see, thanks for the info

If it's just a design project, then go a bit simpler than a full ATX supply. Anything running from the grid needs a decent understanding of electronics to be remotely safe, you'd also be dealing with (depending on country) between 220 and 390VDC on a high value capacitor. A 12v to 1.3v buck converter would be a very similar (and related) project without any of the dangers involved. Basically a fixed voltage version of the mainboard CPU power supply. You could still design it to handle hundreds of amps on the output, as that's what CPU's can draw but it's still a relitively low power.

[17030644]

16 minutes ago, Curious Pineapple said:

If it's just a design project, then go a bit simpler than a full ATX supply. Anything running from the grid needs a decent understanding of electronics to be remotely safe, you'd also be dealing with (depending on country) between 220 and 390VDC on a high value capacitor. A 12v to 1.3v buck converter would be a very similar (and related) project without any of the dangers involved. Basically a fixed voltage version of the mainboard CPU power supply. You could still design it to handle hundreds of amps on the output, as that's what CPU's can draw but it's still a relitively low power.

Ok, a buck converter sounds ok, or just a simpler SMPS without input filtering, apfc, protection IC, etc

[Stefan Payne]

6 hours ago, 17030644 said:

I have no idea on what transformer, inductors, X, Y capacitors, resistors to choose.

Then you need to read a book like the "Powersupply Cookbook" or other stuff.

You also might to want to ask in a real electronics forum, not a PC Forum.

[Unimportant]

11 hours ago, 17030644 said:

<snip>

With the questions you're asking, you probably should not be doing any live mains projects. Not only because of the obvious dangers involved, but also because you won't learn much when you blow up the prototype with every little mistake you make. With a low voltage project you can use a current limited bench power supply and keep your prototype relatively safe.

 

I'd agree with @Curious Pineapple and aim for a buck converter. Check out the TL494 PWM controller. It will handle the PWM generation and most of the loop (might require extra external frequency compensation). You can then design your own synchronous output stage with 2 MOSFETS and a half bridge gate driver. I'm particularly fond of the MIC4605 with automatic dead time control and a low price tag. Read up about MOSFET theory to be able to pick the right parts for your requirements. You can't just haphazardly pick random MOSFETS like you were doing. Other things to look out for are inductor selection (TI has some nice appnotes about this) and proper power supply decoupling. Board layout is absolutely critical or the thing will ring like a bell. Learn what the 2 main current loops in a buck converter are so you can figure out where there's large dI/dt's so you can design the PCB accordingly. Don't try to build any of this on breadboard or prototype board, go straight to manufactured PCB.

 

Then you'll need equipment like a current limited bench power supply and a oscilloscope (a real one, not a toy ebay kit). Check out Siglent and Rigol for affordable but decent low end DSO's. Or find an older second hand analog scope, there seem to be some nice cheap Hameg's out there lately. If you're not prepared to make this investment then forget about the project, you can't measure and troubleshoot something like this with a plain multi-meter, you need to be able to see your PWM signals, ripple, etc... It'll also teach you proper probing techniques because scoping a buck converter will show the naive technician lot's of ghosts.

 

Relevant reading:

http://www.ti.com/lit/an/slva001e/slva001e.pdf

http://www.ti.com/lit/an/slva477b/slva477b.pdf

http://www.ti.com/lit/an/slyt670/slyt670.pdf

http://ww1.microchip.com/downloads/en/AppNotes/00799b.pdf

 

[mariushm]

You can do something with transistors WITHOUT dealing with high voltage.

 

For example, do a basic linear adjustable or fixed power supply, where transistors are used to control voltage or limit current

A classic transformer will reduce 110-230v to a low voltage (let's say 10-30v AC) which you can rectify to DC using bridge rectifier and smooth with a capacitor.

Then use a voltage reference and opamp/comparator to adjust base current on transistor to set output voltage.

 

See the attached files... both contain parts list, schematic, explanations..

The HP one can be simplified by using two separate transformers...no need for custom ones with multiple secondary windings.

---

 

edit: or, you could even go more basic and download a bunch of datasheets for linear regulators and look at the building blocks (darlington transistor, error amplifier, voltage reference etc) ... think how they did power supplies before ICs got cheap

google "linear regulator using discrete components"

see

http://www.rason.org/Projects/discreg/discreg.htm

http://www.learningelectronics.net/circuits/discrete-voltage-regulator.html

http://www.tedpavlic.com/teaching/osu/ece327/lab3_vreg/lab3_vreg_procedure.pdf

https://tangentsoft.net/elec/opamp-linreg.html

 

Attached files:

HP361xA 30w bench series dc power supply EN.pdf

Variable Adjustable Linear Power Supply.pdf

[17030644]

On 4/14/2019 at 10:49 PM, Stefan Payne said:

Then you need to read a book like the "Powersupply Cookbook" or other stuff.

You also might to want to ask in a real electronics forum, not a PC Forum.

Yes I thought it would be a better idea to ask in electronics forum, the thing is I don't know which ones are good, can you recommend some? I only know badcaps.net

[17030644]

On 4/15/2019 at 3:35 AM, Unimportant said:

With the questions you're asking, you probably should not be doing any live mains projects. Not only because of the obvious dangers involved, but also because you won't learn much when you blow up the prototype with every little mistake you make.

I've made high voltage projects before and yes I accept you always end up frying a lot of parts hence I've decided to recycle smps parts instead