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A starting point for Switching Mode Power Supply Design

Hello

I am studying Power Supply Cook Book, MARTY BROWN, 2nd Edition, Newnes Copyright 2001.

I have constructed linear power supplies, I know every details about one zener, one resistor regulation, one zener, one transistor regulation and I know the basis and constructed regulators with three terminal regulators as well as floating regulators.

I have tested and understand characteristics bipolar, some types of MOSFETs and PWM ICs.

I understand how SMPS works in general as well as some specifications. I know very well that to be able to design SMPS well, I need to construct Swith Mode Power Supplies practically. Studying without practical experiments is not good.

The problem here is I do not know where to start with SMPS designs because I am not familiar especially with the ferrite core transformers ( I have designed Iron Core, 50 Hz, Auto Transformers for Voltage Regulators).

And I am worried the first SMPS I construct would not work well.

I am afraid High Voltage Spikes because I just could not figure out what would happen if I do things wrong (especially with turn ratios)

More over I do not have an oscilloscope yet.

My friend told me to try with a relay, a 2M resistor, 1N4007 Diode and a filter capacitor.

Do you have any suggestion?

I am doing all this because I would like to be a real electrical engineer who could design power supplies for any devices. ( I found that almost all of power supplies of consumer and industrial electronic systems use SMPS )

Regards

Reply to
Myauk
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When trying to learn about SMPS, start out simple. Buck, and buck boost supplies only need an inductor, not a transformer. National Semiconductor, and TI web sites are a good source for all kinds of application notes. Also, some of the National literature gives manufacturer's part numbers for inductors, and possibly transformers.

You really don't want to start from scratch, there are many ICs available for various configurations.

Tam

Reply to
Tam/WB2TT

Have a look at the HP Power Supply Cookbook:

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Also, application notes from the manufacturers of SMPS control chips (like Micrel for example) are an excellent source of design info.

Try here for starters:

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You don't need transformers for some types of SMPS's, DC-DC buck converters for example. Start with them and build your confidence in the design and measurement techniques used. Don't play around with mains powered SMPS's until you have the skills.

Go to eBay and get yourself an oscilloscope!!

Dave :)

Reply to
David L. Jones

You certainly want (not need) a transformer for the first stage (AC voltage reduction). It would be much easier to work with a 30V to 60V second stage. Of course, you can switch directly from 300V DC (200V AC), but not really necessary.

Same goes for linear supplies.

Reply to
linnix

An excellent learning tool is available for free. It is LTSpice/Switcher CADIII and it is a PSpice tool for SMPS and general circuit simulation. There are lots of example SMPS circuits included. You can see the waveforms by probing around the circuit with your mouse.

Download @

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Good luck - Roger

Myauk wrote:

Reply to
sailtamarack

Myauk wrote: (snip)

Start collecting ferrite cores, bobbins and magnet wire any where you can scrounge them. Study design guides from the core manufacturers and others:

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(design guide at end of)
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Quite likely, the second, third and fourth also. There is a lot to learn between basic concepts and practical details.

Sorry, I can't imagine developing a good SMPS design without both a good simulator and a good oscilloscope.

You lost me.

Until you get an oscilloscope, you can study, simulate and blow stuff up. And you might even make some supplies that function.

Download a free copy of LTspice, the best switch mode simulator available:

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Study:

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Reply to
John Popelish

Good point. a +12 to +5 V converter might be a good place to start.

Tam

Reply to
Tam/WB2TT

Yes, get one. Perhaps from ebay.

Rene

--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net
Reply to
Rene Tschaggelar

Thank you very much for the resources and suggestions.

I have a good reference book but application notes are essential!

More over I am going to test simulation software.

SMPS with 12 V output should be my starting point.

I will start buying things now. (going to ebay)

I will try to come up with more detailed questions practically and theoractically in six months

Regards

Rene Tschaggelar wrote:

Reply to
Myauk

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