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GOODBYE CLASS "E": WELCOME CLASS D REVERSE "1/D"




 
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August 17, 2022, 03:30:56 AM *
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Author Topic: GOODBYE CLASS "E": WELCOME CLASS D REVERSE "1/D"  (Read 4573 times)
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M0VRF
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« Reply #25 on: July 19, 2022, 05:55:21 PM »

I'm up for that yes please PM me and I'll provide details.
I'd rather pay something, even do a swap or something..?

The sine drive I described was for single ended (15W@12V).

The other versions are push pull, one using an AD9833 driving a dual invertor to square and inv square for both phases and the other design just uses the direct o/p's from an AD9850. Both give around 40-42% duty cycle.
 Altho I'm unable to adj the duty cycle or phase  both designs seem efficient enough and are very simple build.

When I first did my experiments and simulations some 15 years ago small variations in the duty cycle just seemed to alter the tuning and then I retuned to restore the peak efficiency.

Let keep it going on!



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KJ7AGO
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« Reply #26 on: July 20, 2022, 01:22:46 PM »

Duty Cycle:
My experience with duty cycle and the CMCD amps is that you should get as close to 50% as you can.  Apparently, CMCD are more sensitive than other switchers:
(see photo)
Symmetry between banks is more important than the actual number.  Obviously you can only get as close to 50% as the speed of your circuit will allow.  For me at 20m that is around 48%, and the drop in efficiency as I got away from it is noticeable.
Efficiency aside, getting the most out of your transistors/circuit means maximizing the on time (area under the curve and all).

MOVRF- PM sent

Chuck KJ7AGO


* Drain efficiency vs duty cycle for PAs.png (332.34 KB, 1530x882 - viewed 48 times.)
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