I am looking for help evaluating a new line of inductors my company is developing specifically for Class D inductors. We have completed the design and evaluation from a magnetics point of view and have had a couple of our parts qualified on the IRAUDAMP7D and the IRAUDAMP7S reference design from IR. Unfortunately, neither I nor any of our engineers feel qualified to evaluate their performance by listening to the sound quality.
I'm interested in offering free samples in exchange for feedback on audio performance. Of course, if anyone can provide quantitative test results to back up their subjective evaluation it would be more the we can ask for but appreciated greatly. We have three series available, each with 10, 15, 22 and 30uH values. If you are interested, let me know and I can send our preliminary data sheets to you.
I'm interested in offering free samples in exchange for feedback on audio performance. Of course, if anyone can provide quantitative test results to back up their subjective evaluation it would be more the we can ask for but appreciated greatly. We have three series available, each with 10, 15, 22 and 30uH values. If you are interested, let me know and I can send our preliminary data sheets to you.
I've tried to attach the catalog pages. These use gapped ferrite in a new core shape made for Class D applications. The advantages of the cores shape are shielding and a small winding area vs cross section since the inductance values are not large. The ferrite is made by a Japanese manufacturer and has a relatively stable permeability over temperature.
Parallel capacitance of output inductors (i.e. total capacitance per finished coil) and series inductance of the cap parallel to the load make the output filter behave less like a lowpass filter with raising frequency. Unfortunately it is the higher frequencies that are responsible for a class-d amplifiers external (i.e. speaker wires etc) EMI radiation.
If you make this capacitance as low as possible by the use of a clever design (like avoiding multiple layers of windings for instance) you help the class-d designer designing for low EMI.
Regards
Charles
If you make this capacitance as low as possible by the use of a clever design (like avoiding multiple layers of windings for instance) you help the class-d designer designing for low EMI.
Regards
Charles
We have a new method for gapping ferrite toroids. We have used these in SMPS output filters up to 60A but have not used them in a Class D app. I have read where a gapped ferrite toroid may have advantages in this type of app. If you are interested in evaluating the performance using a gapped toroid, let me know the inductance you need and the switching frequency, we might be able to send a sample for evaluation and feedback.
Yes, we would be interested in testing your inductors. Our company is Class D audio and you can see some of our products at Class D Audio Home page You can contact me directly at tom@classdaudio.com and provide me with more information. We are located in California.
Tom
Hi Ice,
Frequency=250kHz
Isat must be greater than 70A
Inductance=40uH[micro henries]
DCR=must be less than 0.05ohms
do let me know, if you can provide this. my email is
amp_man_1@hotmail.com
Frequency=250kHz
Isat must be greater than 70A
Inductance=40uH[micro henries]
DCR=must be less than 0.05ohms
do let me know, if you can provide this. my email is
amp_man_1@hotmail.com
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29 turns on two stacked T184-2 micrometals toroids, does anyone know a simpler or more compact approach? I don't. That's 100mJ energy storage!
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