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Understanding of suitabily of ferrite grade materials for resonant tuned circuit

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Sparks_nz:
HI,
I want to wind 2 resonant inductors, with resonant frequencies of 160kHz and 224kHz, and am looking at the various ferrite materials datasheets to see what grade of ferrite are suitable for this use and the freq band of operation.
I have some EPCOS N48 and N30 cores that I could use, however the datasheet for N48 says it is suitable for resonant inductors but only up to 100kHz. The N30 datasheet says its suitable for use up to 400kHz, but useage listed as a broadband transformer, so I presume its not suitable for use as a high Q resonant inductor. I cant see any other grades of material that are readily available that would be suitable.
Can someone please advise me on whether the N48 will indeed work well (high Q) at the 2 frequencies I need, and whether the N30 will also work well as a resonant inductor with high Q, even though it states use as a broadband transformer. I dont understand how the useage is determined for the various grades of material.
thanks and regards,
JEFF

Jwillis:
Here's a PDF that has the various materials and applications. https://www.cwsbytemark.com/CatalogSheets/Ferrite_datasheet_oct06/FR_MATL.pdf
Here's some insight on how the composite structure also defines the core characteristics. https://www.ti.com/lit/ml/slup124/slup124.pdf

But generally any ferrite materials should be  have frequency ranges of several MHz  160kHz to 224kHz shouldn't be a problem.
But your probably looking for a NiZn type 67 ferrite material for high Q.
I'm no expert but I hope I helped some.

regards

jonpaul:

Sorry, but The design of a resonant mode soft switching power supply does not begin in this manner.

Learn about resonant MODE PSU design de théorie in the many books, papers, seminars openly available

Especially reccomend the books and papers by our old friends Dr Richard REDL and Nathan Sokol, inventor of class E mode.


For core and materials suggest the old Ferroxcube/Philips/ Siemens ferrite core catalogues and applications notes

Nowadays TDK EPCOS and Fair-Rite have similar.

Matériel sélection will be by FIRST what is the thruput power?

Then, frequency, losses, operation  Hotspot temperature. But Cost and availability drive the selection, as many cores sizes and shapes are available only in a limited choice Finally you need a power matériel not wideband !!!

Bon courage

Jon

Sparks_nz:
Thank you both for your replies and the links to material. I will study this.
My application is a low power oscillator, where the resonant circuit is tuned to a harmonic of the input drive frequency.
In looking at the ferrite material applications, it seems to me that the recommended materials for high Q resonant circuits (such as #67) all have very low permiability (ui=40)and hence low AL value when winding, requiring perhaps several hundred turns to create a 10mH inductor for example, which I presume would have high parasitic capacitance. So it is puzzling for me to see why such a material would have a high Q, compared to a medium permiability core such as N30 (ui=4300), which is designated for broadband transformers, which would only require say 50 turns to create the same10mH coil, but with minimal parasitic capacitance. Can someone please comment on this observation, as it is bugging me, and I presume Im not seeing things clearly.
regards and thanks,
JEFF

Jwillis:
I may be way off here but Ni-Zn ferrites  seem to be capable of very high Coercive Field (which is defined as  "the strength of the electric field at which the macroscopic polarization of the ferroelectric capacitor disappears" and/or "is a measure of the ability of a ferromagnetic material to withstand an external magnetic field without becoming demagnetized.")
At the same time having a low Remanence or residual magnetism which is the magnetization left behind in a ferromagnetic material after an external magnetic field is removed.
I'm a little lost on the Coercive Field but seem to understand Remanence or residual magnetism.

Maybe being able to hold a stable field from external disruption in combination with the ability to "clear" the magnetic field quickly when a current is removed from the coil determines the Q ?
But I'm uncertain as to the difference between one number ferrite to the next. It appears to be the crystalline structure of the material  and percentages of the various elemental metals used.

Just so much to absorb.

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