I made push-pull smps working on 50 khz. It has up to 90-120w power (input voltage 12v and output 24v). For transformer i am using two ferrite toroids on top of each other, it's a old USSR toroids with initial permeability 2000 (there is a link, for more information) / out diameter-45mm/ inner diameter-28mm/ height-8mm/ and together 45mm/28mm/16mm. I know that modern toroids have much higher permeability and high saturation current, therefore i can use relatively small toroid. Question is, where i can buy toroids that i can use for my project? Can anyone suggest good selector program or calculator? thanks in advance.
closed as off-topic by Ignacio Vazquez-Abrams, The Photon, Daniel Grillo, Matt Young, Leon Heller May 8 '15 at 16:44
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "Questions seeking recommendations for specific products or places to purchase them are off-topic as they are rarely useful to others and quickly obsolete. Instead, describe your situation and the specific problem you're trying to solve." – Ignacio Vazquez-Abrams, The Photon, Daniel Grillo, Matt Young, Leon Heller
Modern materials are probably not vastly better than old ones for power use.
Iron powder power toroids may still be the best solution.
"Micrometals" make a good range and have design guides.
ARNOLD are also a well known brand - and I see that they are now also part of Micrometals.
You can download Micrometals Inductor design software here**
I have no vested interest in Micrometals - I used their products in production volumes long ago and found the company helpful and the product of good quality.
WARNING - Micrometals products are well enough known that other manufacturers produce lookalike products. They may not be work-alike. An important aspect of powdered iron cores in having a binder that tolerates induced thermal energy across the design lifetime. Inferior binders break down earlier or much earlier with higher temperatures causing core material changes leading to increased thermal losses leading to ........... thermal runaway and destruction.