150uh - 62khz-500khz Ferrite Which Core?

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Oh... The above assumes that you want 900W continuous rated power. If you assume music is 1/8 continuous then you can use a higher number for J, current density in the wire, and end up with a smaller inductor. You still have to design to avoid saturating the inductor based on the peak current though.


Once again why 150uH


the value of the inductance in this circuit is 150uh. For him.
 

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If you just have the circuit diagrams then ???. You suggest you have measured a coil. Was that on a physical example of the amplifier? I assume that is the case because you suggest you have already blown one up... Or is this something you have made yourself based on an incomplete circuit diagram?


The circuit diagram shows a 470nF output filter capacitor which, with a 4R load, would suggest an 80KHz cut off frequency and an 8uH inductor.


However the above applies to fixed frequency operation but it is still the case that 150uH in that position is a huge and likely to be wrong value. Given the circuit is self oscillating 150uH is going to make it go at some silly low frequency in the first place.


I would be inclined to go for a 1uF filter capacitor and a 16uH filter inductor and see if it manages not to die so quickly.
 
I assume you are trying to copy the board? If the zero bias value of the inductor is in fact 150uH then as previously suggested it is possible that it is a soft saturating material... a swinging choke. I still doubt that. Have a look at,


Class D Amp with LM566, LM393 and 2XIRF530


It is a similar circuit but L1 is 30uH with C16 470nF which would be values consistent with an 8R load, root(L/C)
 
Sorry? I don't really mind if you are copying it. I assumed you already had one but perhaps it had blown up. However inductors are, more or less, indestructible. I presented the other circuit as being similar. I'm not suggesting you use it instead. It just demonstrates that a reasonable value for the output inductor in this sort of circuit is 30uH rather than the 150uH that you are suggesting you need.
 
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