Class D audio, and motor speed control

I found this tutorial on Class D audio circuits:
http://www.irf.com/product-info/audio/classdtutorial606.pdf

and noticed there is no freewheeling diode, as there is in motor control circuits.

Why is this?

Thanks,

Michael

 

[Massoud]

mrdarrett@gmail.com wrote in
news:59bf99bd-9e7a-4901-b7c6-14209fd25994@googlegroups.com:

I found this tutorial on Class D audio circuits:
http://www.irf.com/product-info/audio/classdtutorial606.pdf

and noticed there is no freewheeling diode, as there is in motor
control circuits.

Why is this?

Thanks,

Michael

It is embeded in the device. (page 9)


Mass





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[Phil Allison]

<mrdarrett@gmail.com>

I found this tutorial on Class D audio circuits:
http://www.irf.com/product-info/audio/classdtutorial606.pdf

and noticed there is no freewheeling diode, as there is in motor control
circuits.

Why is this?

** Huh ?

How would a speaker operate with a diode across it ??

In a motor drive the diode keeps DC current flowing in the motor - the last
thing you want with a speaker.


..... Phil

 

"I found this tutorial on Class D audio circuits:
http://www.irf.com/product-info/audio/classdtutorial606.pdf "

Yeah, a half assed sales pitch is what it is.

Fucker claims a better switching chaarcteristic in the devices improves audio response. Absolut rubbish. When you get to class D all you need is to drive the thing right and you got all the linearity you need.

The article did correctly state though that output filters can be troublesome. For example if not air core indunctors, there is that saturation problem. Some capacitors do not behavre perfectly, especially if you're fucking cheap.

Actually you cna deal with that if you try. Yeah... You can deal with damnear anything. Almost.

 

On Monday, July 28, 2014 4:27:16 PM UTC-7, Phil Allison wrote:

mrdarrett@gmail.com



I found this tutorial on Class D audio circuits:

http://www.irf.com/product-info/audio/classdtutorial606.pdf



and noticed there is no freewheeling diode, as there is in motor control

circuits.



Why is this?



** Huh ?



How would a speaker operate with a diode across it ??



In a motor drive the diode keeps DC current flowing in the motor - the last

thing you want with a speaker.





.... Phil

True.

What I meant to say was, I am impressed that two mosfets can drive an inductive load without even needing heatsinks, whereas when I tried to control a large motor with an IRF530, I melted the mosfet.