Hi darkfenriz
This is not a UCD amp, so I don’t need the ripple.
You will see some ripple if you look closer and of course at lower output the ripple will be easier to see.
Cheers
It’s a self oscillating design, so as you know the switching frequency is not fixed, but it never drops down to a scary frequency.
It’s not a UCD, but more like an analogue frontend with a Class D buffer.
Yes the output filter is more than just an L and C.
Cheers
'THD numbers look impressive! That's neat - I use OrCAD 16 at work. Keep us updated on your project, and good luck.
JRF
You've still provided very little information.
I can only suspect you've chosen a very high carrier frequency that allows a lot of feedback. Harmonics reveil that.
Simulate 3+7kHz IMD and check the distortion products in the range of 10-21kHz, is the number still looking so nice as 5E-3% ? I bet it doesn't.
Also if your switching frequency gets higher than some 200-300 kHz, then use simulation only for proof of concept, not for THD estimation (useless).
Mvh
I can only suspect you've chosen a very high carrier frequency that allows a lot of feedback. Harmonics reveil that.
Simulate 3+7kHz IMD and check the distortion products in the range of 10-21kHz, is the number still looking so nice as 5E-3% ? I bet it doesn't.
Also if your switching frequency gets higher than some 200-300 kHz, then use simulation only for proof of concept, not for THD estimation (useless).
Mvh
Hi
JRF
Thank you.
df
I know there are some limitations in simulation compared to real circuits; this is a new concept so I’m using the simulator to check if the concept looks interesting, and I think it does. I’m not that concerned about the THD right now, but in the simulation I’m now down in the E-4 range.
I didn’t know about the frequency limitation in Orcad Pspice, I will have to ask syn08 about that.
The frontend I’m using is this one: http://www.diyaudio.com/forums/showthread.php?t=145190
I’m not using any global feedback, but of course some feedback in the frontend and also in the Class D buffer.
I’m still working on the circuit so I don’t want to reveal too much before I’m sure that it’s a working concept.
Cheers (Mvh)
JRF
Thank you.
df
I know there are some limitations in simulation compared to real circuits; this is a new concept so I’m using the simulator to check if the concept looks interesting, and I think it does. I’m not that concerned about the THD right now, but in the simulation I’m now down in the E-4 range.
I didn’t know about the frequency limitation in Orcad Pspice, I will have to ask syn08 about that.
The frontend I’m using is this one: http://www.diyaudio.com/forums/showthread.php?t=145190
I’m not using any global feedback, but of course some feedback in the frontend and also in the Class D buffer.
I’m still working on the circuit so I don’t want to reveal too much before I’m sure that it’s a working concept.
Cheers (Mvh)
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