close loop pwm class d design problem

[st01liyp]

I want to desing a pwm class d PA, i think the open loop is no good, so i want to design a close loop class d.

the problem is: I want to know how the hormonic distortion comes up(I guess it caused by alias), and how the loop suppresses this distortion?
Any one know this ? or any book mentions this?

 

[montage3000]

open loop is poor

 

[bluesmaster]

dead time, power pump,finite swith ron, quantization error....................to many causes

 

[st01liyp]

In close loop form, I think the swithing wave form would come into the PWM modulator, which would cause aliasing, may be this is the overwhelming source of distortion, I guess.

I am not sure about how to design the loop. Is there any good articles would help?
thanks!

 

[papu]

in close loop form

 

[Kral]

st01liyp,
The 27th AES International Conference is devoted entirely to the topic "Efficient Audio Power Amplification". Copies of the proceedings can be obtained by visiting h**p://www.aes.org.
Regards,
Kral