Where's the ripple?
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
So what's the switching frequency and output filter?
Is that a clocked design with multiple LC resonant traps?
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
Hi
This is the simulations of my class d design.
Does it look ok?
Cheers
Stinius
'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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