Inexpensive DC-DC converter/SMPS design idea and suitable topologies

[Tony Stewart]

Simple does not get you great specs. He must have made flybacks beforehand the chip proposed looks simple in parts yet is far from simple. Harmonic aliasing of cascaded Bucks needs careful design to avoid cross step load errors.

 

[ronsimpson]

He must have made flybacks beforehand

No. He as this same question on at least two forums. It appears he has no experience. Link to All About Ele.

Simple does not get you great

Complex = will not happen.
Simple = maybe he can get it done. With help from everyone.

 

[MD MUBDIUL HASAN]

No. He as this same question on at least two forums. It appears he has no experience. Link to All About Ele.

Complex = will not happen.
Simple = maybe he can get it done. With help from everyone.

Ok. Lets say I have no knowledge on it.
Now come in just a one design. Other forum you said flyback needs high voltage MOSFET.
Its fine.

 

[MD MUBDIUL HASAN]

Here is an example. TI You will need to remove the PFC part of the design. I think it is only 150 watt.

Did you see its design parameters? Does it applicable for wide input range.

 

[MD MUBDIUL HASAN]

He needs simple. This project is too much for the first one. It is way beyond his skill set. One option is this circuit to make 24V and then add two simple buck circuits to get 12 and 5.
View attachment 134508View attachment 134510View attachment 134511
Hi Tony, If you want to teach him how the below circuit works go ahead. Neither of us are getting paid to teach today. Choose a simple option.
View attachment 134509

Among all lets take first one UCC28740. In post # 12, infineon solution looks expensive.
I am tryng to calculate parameters. Lets change the transformer turns ration, inductance and so on.

 

[ronsimpson]

You need some tools and a chance to play with a circuit.
Here is a 400VDC to 24V isolated flyback. Not what you want but a start.
Attached is a file. Down load LTSPICE and put it on your computer. Then open my file.
You should see the schematic. Click on "run" and wait for a while. Click on the output voltage. It will take 150mS for it to start and make voltage.
This is a good place to learn how things work and what happens when changes are made.
Save the schematic to a different name before making changes so you can get back.

Red trace is the voltage on M1.
Good luck
RonSimpson

 

[MD MUBDIUL HASAN]

You need some tools and a chance to play with a circuit.
Here is a 400VDC to 24V isolated flyback. Not what you want but a start.
Attached is a file. Down load LTSPICE and put it on your computer. Then open my file.
You should see the schematic. Click on "run" and wait for a while. Click on the output voltage. It will take 150mS for it to start and make voltage.
This is a good place to learn how things work and what happens when changes are made.
Save the schematic to a different name before making changes so you can get back.

View attachment 134513
Red trace is the voltage on M1.
Good luck
RonSimpson

Yes. Great!
I have LTspice in my PC.
It will be fun to play with it.
Thank you!

 

[rjenkinsgb]

How did you become good engineer without homework ? Did you climb top of the tree in the first day?

Not at all - but I did not ask other people to do it for me, or create or format reports and reasoning for me:

I have no problems with questions and helping people, but doing homework for them is a step too far.