diyAudio (
-   Power Supplies (
-   -   SMPS Transformer Turns Equations Help (

venki 21st January 2006 05:01 PM

SMPS Transformer Turns Equations Help

I am planning to make an SMPS for my new ampilfier. It requires a power supply of +-20 V 10A (rms). I would like to know the equations for Calculating
1. the number of turns in primary/Secondary

2. the guage of wire to be used.

I intend to use 230V ac (rectified) as input. It would be of great help if somebody could post the equations.

Thanks in Advance,


poobah 21st January 2006 09:04 PM

This application note applies to a specific part... which would not work for you... but it is still a good collection of data & formulas.

You will be looking for a "buck" or "forward" convertor.



N-Channel 13th February 2006 07:16 PM

Turns Ratio

Here is a laundry-list of books I regularly recommend to members asking questions about SMPS design in general, or specific ones about the different sections of a Switcher:

1) High Frequency Switching Power Supply Design - Geo. Chryssis (c) 1989 (Don't know ISBN) :confused:

2) Power Supply Cookbook (EDN Series for Design Engineers)
by Marty Brown; 2nd edition May 2001 ISBN: 075067329X

3) Switchmode Power Supply Design - Abraham I. Pressman (Don't know year or ISBN) :confused:

Chryssis' book is, perhaps the best on transformer design. He includes design procedures for both Forward and Flyback topologies. I have used his procedure to design many SMPSs with great success! :cool:

Hope this helps!

Steve :D :cool:

cerrem 14th February 2006 10:48 PM

Hi Venki.....
I believe I Emailed you a few weeks ago regarding this design...
I need much more info.....
What is the input voltage range for this switcher....
I recomend a Push-Pull converter in current mode...


jackinnj 16th February 2006 02:02 AM

got Excel?
here's a link to a spreadsheet I cobbled for push-pull converters -- works pretty well with the Linear Tech series of switching chips so it should work with others:

All times are GMT. The time now is 04:17 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 18.75%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio