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Class D Switching Power Amplifiers and Power D/A conversion

Class D investigation.
Class D investigation.
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Old 12th February 2019, 06:33 AM   #131
Grizlek is offline Grizlek
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Join Date: May 2010
Quote:
Originally Posted by kees52 View Post
I have now I am waiting for parts, dis some sims with 5 and 8 level switching stuff.


The found stuff about the postfeedback with formulas do quite nice, I have use a 8 level, x 8 carrier is 2 Mhz and 100 Khz -3 low pass, maybe I can even go higher.

I do not now however how the switches go behave, because of the 8 levels, do go this into problems with audio, normally with a inverter for only 50 hz that is quite more relaxed then.

However I get with deadtime (if this is needed there?) quite low distortions, also on 20 Khz.


regards

May we see the schematics of this 8 level ? Signals do look very nice
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Old 12th February 2019, 06:31 PM   #132
kees52 is offline kees52  Netherlands
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Join Date: May 2009
Location: Sprang-capelle Holland.
Grizlek here are the 5 level class D and the open loop distortion, it is sim so in real live things get much worse, or I am lucky if not.

have include also a twree level self oscillating version, just build it, I like to see how it works in real live.

The 5 level has postfeedback however making the feedback filter oke, it needs calculation, carrier is x 4, so 250 Khz get 1 Mhz, can use smaller mosfets power gets evenly divided over mosfets..

Lib's are to big for put here, search on internet for them. or go here

For LTspice users. Libraries of models, examples, etc

regarts.
Attached Images
File Type: jpg ScreenHunter_2043 Feb. 12 18.54.jpg (237.5 KB, 49 views)
File Type: jpg ScreenHunter_2044 Feb. 12 19.28.jpg (383.9 KB, 43 views)
Attached Files
File Type: asc 8 level class D-openloop.asc (29.6 KB, 4 views)
File Type: asc 5 level nonoffset-triangles-flycap3-oke5.asc (21.5 KB, 2 views)

Last edited by kees52; 12th February 2019 at 06:39 PM.
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Old 13th February 2019, 06:25 AM   #133
Grizlek is offline Grizlek
diyAudio Member
 
Join Date: May 2010
Quote:
Originally Posted by kees52 View Post
Grizlek here are the 5 level class D and the open loop distortion, it is sim so in real live things get much worse, or I am lucky if not.

have include also a twree level self oscillating version, just build it, I like to see how it works in real live.

The 5 level has postfeedback however making the feedback filter oke, it needs calculation, carrier is x 4, so 250 Khz get 1 Mhz, can use smaller mosfets power gets evenly divided over mosfets..

Lib's are to big for put here, search on internet for them. or go here

For LTspice users. Libraries of models, examples, etc

regarts.

How would you in real life make phase shifted triangles? And THD will be affected if that phase shift is good?
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Old 13th February 2019, 11:56 AM   #134
kees52 is offline kees52  Netherlands
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Join Date: May 2009
Location: Sprang-capelle Holland.
Quote:
Originally Posted by Grizlek View Post
How would you in real life make phase shifted triangles? And THD will be affected if that phase shift is good?

Maybe like this? or use a chip and program it in it, there are a lot of nice cpu's like a FPGA chip.

You can go read over multilevel inverters on google a lot of info there.


I think more then 5 level for audio is because of parts count maybe not such idea, but you can set frequency to 150 khz and get on output 1.2Mhz making even output low pas higher and get 150 Khz bandwidth amp, but it is complicated for postfeedback.

Oke I get the parts for the circlotron so get to work after weeks of waiting because of other work and friend who did contract cancer and needs help, she did survive and is in remission.

regards
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File Type: jpg ScreenHunter_2046 Feb. 13 12.32.jpg (132.6 KB, 22 views)
File Type: jpg ScreenHunter_2047 Feb. 13 12.39.jpg (206.8 KB, 23 views)
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