Trying to design an SMPS, Stuck on working out the cores.

L

Light

New member
Hello diysmps,

Im just getting into SMPS design and im trying to work out a few things.

How can i work out how much power each core is capable of safely?

I have various cores:
ETD34 3C90
ETD44 3C90
ETD59 3C90

is there any way i can work it out?

Also trying to find the equations useful for design.

The topologys i am interested in using are mostly Half-Bridge and Full-Bridge.
I can sort that part out myself mostly, however i need more information on designing and winding the cores


Huge thanks for anyone who can help out!
 
L

Light

New member
MicrosiM said:
Check here first

http://www.diysmps.com/forums/showthread.php?72-Necessary-Equipments-needed-for-SMPS-development


The power of each core depends on frequency, so I think you will get around 3KW from ETD59 @80khz for example

Hope that helps
Click to expand...

Thanks for that. Thats some useful information.

Already seen it however, i have most of the gear now. only difference is my scope is 50MHz. Ordering a pair of x100 probes...

Also is there any reason you should not use more then one probe? I haven't had any problem doing so.
 
MicrosiM

MicrosiM

Administrator
Staff member
Light said:
Thanks for that. Thats some useful information.

Already seen it however, i have most of the gear now. only difference is my scope is 50MHz. Ordering a pair of x100 probes...

Also is there any reason you should not use more then one probe? I haven't had any problem doing so.
Click to expand...


50Mhz will do the Job, just get those x100 Probes.

No need to try connecting two probes to the same SMPS while its running, simply because you will connect two points together, because of common GND of your oscilloscope.


So , don't try that, even you think it will work !!!: :x:
 
L

Light

New member
MicrosiM said:
50Mhz will do the Job, just get those x100 Probes.

No need to try connecting two probes to the same SMPS while its running, simply because you will connect two points together, because of common GND of your oscilloscope.


So , don't try that, even you think it will work !!!: :x:
Click to expand...

Well i never had a problem doing it. I just always connect the grounds to ground. Its likely because when ive been developing SMPSs ive always been doing it with my 70V 20A power supply. I haven't tried a higher voltage yet, however when i do, i will be using my isolating transformer. (2 site transformers in series input parallel output)
 
L

Light

New member
I wouldn't mind some more information on calculating the power and so on. Expecially where equations actually come from. if you could... i would be very greatful.

I have a huge thing at trying to be accurate so i don't like doing too many approximate stuff.
 
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