Sigma-Delta Audio Amplifier

[samanchon]

sigma-delta modulation amplifier

I'm new to sigma-delta modulation with a little background about one. Now i'm trying to design Class-D power amp using SDM scheme. Please tell me how should i start to design it. thank tou

 

[skal81]

I think you should start by fixing your architecture (loop filter order, OSR...) using system simulation (matlab/octave -> See Schreier's toolboxhttps://www.mathworks.com/matlabcentral/ fileexchange/loadFile.do?objectId=19). Then add the parasitics (opamp BW, SR, thermal/ktC noise... -> See the article by Brigati **broken link removed**) and determine the spec of the opamp. Then you can start the design.
A few points:
- for class D amp dont' use an OSR too high (you need to drive the power switch)
- take care of flicker noise (human ear can hear it)
Hope it helps a little
good luck

 

[bimbla]

If Class-D Audio amplifier is your target, try looking at AD1991 from Analog Devides, LM4651/52 from National semiconductors.

If you want something out of this world, visit the website of D2audio.

bimbla.